Monthly Archives: April 2018

How A Manual Chain Hoist Works?

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From What Parts A Manual Chain Hoist Consists

Manual chain hoist is a pretty simple device considering the large amount of weight such a tool can lift. Chain hoists are made from durable, high grade steel to ensure safety and reliability when lifting couple of tons heavy loads. Manual chain hoist can be separated in three different part categories: lifting chains, lifting mechanism and hooks.

 

Chain hoist has got two chain loops – hand chain and lifting chain. Hand chain sits on a wheel located in the lifting mechanism; it needs to be pulled by hand in order to lift a load. The wheel inside the lifting mechanism has got special pockets that allow the hand chain to move the wheel. Lifting chain also loops the lifting mechanism and lifts or lowers a load. At the end of the chain there is a grab hook, where you can attach lifting chains or slings, a load leveler or load itself. There is also a hook on the top of the chain hoists housing. This hook is used to attach the hoist to a ceiling mount, trolley system or other construction that can withstand the weight a hoist will lift. Most chain hoists have swivel hooks, meaning that they can be turned 360 degrees around to allow for easier mounting. The lifting mechanism consists of a cog, axle, drive shaft, gears and sprockets. There is also a chain stopper or brake on most chain hoists that prevents load from lowering under a load.

 

How A Manual Chain Hoist Works

The physics behind a chain hoist are very simple and have been used for lifting heavy objects for a long time. Chain hoist uses a mechanical advantage to transform small force over a long distance to large force over a short distance; this is possible by using multiple larger and smaller gears in the chain hoist mechanism.

 

To lift a load, chain hoist operator needs to pull down the hand chain; this turns the cog and axle which goes through the lifting mechanism. Inside the lifting mechanism are multiple gears which increase the mechanical work applied when pulling the hand chain for dozen times using gear ratio, allowing to easily lift loads with multiple ton capacity.

 

So when the hand chain is pulled, the cog which is rotated by the hand chain turns the drive shaft and gears which turn the load chain sprocket, this also rotates the load chain that is looped over the load chain sprocket and lifts a load. Larger gears move slower than smaller gears, but create more force; this is why chain hoist lifts load very slowly when compared to a hydraulic hoist. At the end of the lifting chain is a grab hook, which allows easily attaching and detaching a load. Also, most chain hoist lifting mechanisms have a ratchet or braking system that prevents the load from slipping back, but allows lowering a load by pulling the other side of the hand chain.

 

Manual Chain Hoist In Comparison With Other Hoist Types for Engine Lift

Chain hoists have different uses, for example in construction sites, shops, warehouses, also in car service stations and other application, where precise lifting is required.

 

The Disadvantages Of Manual Chain Hoists For Engine Lifting Are:

 

  • They are slower than other type of hoists;
  • They have special requirements for installation areas, which limit places these hoists can be used, in opposite hydraulic hoists just need a solid and level ground.

 

However, There Are Also Some Advantages For Using Manual Chain Hoists For Engine Lifting:

 

  • They don’t need electricity, oil or other additional resources to work;
  • They are cheaper than electric or hydraulic hoists;
  • They are simple to use and easy to repair and maintain.

 

If you need more information about manual chain hoists, try to visit Cheng Day Machinery Works Co., Ltd. – the company specializes in producing wire rope hoist, electric chain hoist, crane components, chain hoist trolley, etc. Get more details please send inquiry or contact with Cheng Day Machinery.

 

 

Article Source: http://www.knockoutengine.com/how-a-manual-chain-hoist-works/

How to Decide Between Electric, Pneumatic and Hydraulic Actuators

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Fluid power is a well-established technology; but in case you haven’t noticed, electric actuators have come a long way in the past ten years. But does that mean that fluid power systems are obsolete?

 

To answer that question, I spoke to experts from automation suppliers Festo and SMAC. Festo carries both electric and pneumatic technology, while SMAC specializes in a variety of types of electric actuators from ball screw-driven devices to linear motors.

 

According to Jim Ackert, applications specialist at Festo, fluid power systems may not be going anywhere. In many applications where they were once ubiquitous, however, electrics are pushing in.

 

“For the time being, I think all three technologies have their place in industry,” said Ackert. “But, the flexibility of electric drives, coupled with the fact that the price of electric components has been steadily coming down over the years, makes them more popular and affordable than they once were.”

 

Tradeoffs Between Electric, Pneumatic and Hydraulic Actuators

 

It may sound frivolous, but choosing the right actuator motor technology is a lot like choosing a role-playing game character: the Fighter, Mage and Thief are classic character archetypes in video games, with trade-offs in damage, health and speed. When it comes to actuators, the trade-offs are force, positioning accuracy and speed.

 

In general, the overlap between the force and speed capabilities of fluid and electric actuators is growing. Electric actuators are even making their way into heavy equipment presses and other traditionally hydraulic-dominated markets.

 

Flexibility

Some applications require more flexible equipment than others. Similarly, the different types of actuators vary in flexibility. Because of this, considering flexibility is often a good place to start when deciding on an actuator.

 

For this consideration, you need to look at your application. Will your setup need changes in the future? How many positions will your actuator need to reach?

 

For example, if you are picking objects from one conveyor and placing them onto one of two conveyors, you need three positions. With pneumatic cylinders, this would require at least two cylinders, either set against one another or set up separately, one for each conveyor. With electrics, a position can be set at any point along the device, and you can easily program multiple points.

 

Taken as a whole, electrics are also the most flexible when it comes to force. Take this Curtiss-Wright ballscrew-based actuator, which pushes up to 40 short tons. At the other end of the spectrum, linear motors breeze by at up to 10 m/s (in the case of Festo’s toothed belt actuators). This broad range of specifications means that whatever your needs are, there is an electric device out there that fits them.

 

If your application is high-mix, in the sense that your setup will need to handle extremely high forces as well as lower forces, it can make sense to choose a hydraulic system, ensuring that your actuators will be able to handle any force you throw at it.

 

In terms of flexibility, the primary benefit to pneumatics is that they are simple to install and operate. If you need to change from a 6” stroke to a 12” stroke, it will be relatively simple to swap the cylinder. However, this wouldn’t be preferable in a real-world situation—and if more complex changes are needed, the time and cost will start to add up.

 

Cost

The biggest disparity between what you see at trade shows and what’s really in use on shop floors across the country is the practicality of cost. Sure, that collaborative robot tending a 3D metal printer while streaming data to an iPad is cool, but is it practical?

 

For manufacturing engineers, the name of the game is to get the job done efficiently and on budget. That’s part of the reason pneumatic actuators probably aren’t going anywhere, despite being made technically obsolete by advances in electric technology—and electric motors and drives are getting cheaper every year. Still, comparing Bimba’s original line of pneumatic and electric linear thrusters shows that the electric version costs approximately five times more.

 

Hydraulic systems are the most expensive, and require the most maintenance and equipment to operate.

 

Types of Electric Linear Actuators

Mechanisms of electric linear motion range from ball screws to rack and pinion gears, to linear motors. Each has different strengths and weaknesses.

 

  • Screw Driven Actuators

According to Helix Linear Technologies, there are two main types of screw-driven actuators: ball screw and lead screw. Ball screw-driven actuators convert the rotary motion of a stepper or rotary motor to linear motion by means of a ball screw and ball nut arrangement.

 

In essence, this mechanism takes the principle of a nut riding on a threaded rod and adds ball bearings to decrease friction. However, these mechanisms are not self-locking, and depending on the application may need additional braking mechanisms, such as vertical installations. Ball screws also require regular lubrication.

 

Where a ball screw uses bearings to decrease friction, the lead screw uses a low-friction polymer or bronze nut. The lead screw is therefore much less expensive than other types of linear actuator, but the friction is higher. This means you may need higher motor torque to drive the same load on a less-efficient lead screw mechanism than for a comparable ball screw actuator. The added friction also increases wear and operating temperature, and lead screws need to be replaced more frequently than other types of actuators.

 

Screw drive actuators can deliver extremely high forces, because the force is distributed along the entire helical path of the nut around the screw. They can also be highly accurate. However, drawbacks to this system include faster wear than non-contact systems. According to Ed Neff, President of SMAC, you can reasonably expect a ball screw to wear out in the same time frame as a pneumatic cylinder in certain applications.

 

  • Belt and Gear-Driven Actuators

Belt-driven actuators are like conveyor belts. According to Misumi, belts are typically made of fiber-reinforced elastomer, and usually have teeth for interfacing with the pulleys to eliminate slippage. A carriage rides on top of the belt to carry the payload.

 

The interesting thing about belt systems is that they scale in travel distance more efficiently than screw drive systems. All you need is a longer belt, rather than a longer precision machined helical screw. Another advantage of belt-driven actuators is that they have fewer moving parts, so maintenance is simpler. However, belts will require re-tensioning as part of scheduled maintenance.

 

Belt-driven systems are not ideal for high loads due to the need for thicker belts and their susceptibility to shock loads. Because belt materials are often prone to elongation over time, accuracy eventually suffers.

 

While belt drive systems win out over screws on travel distance, belt tensioning becomes difficult at longer distances. In these situations, according to Danielle Collins of LinearMotionTips.com, rack and pinion systems win out. Rack sections can be laid out to virtually any length.

 

Some rack and pinion systems use a fixed rack and moving pinion, while some use a fixed pinion and moving rack. At longer stroke lengths, moving pinion systems are more efficient because the moving mass is lower. However, cable management is essential in these cases.

 

In gear systems, backlash is always a consideration, but today’s high-precision machining can deliver micron accuracy in gear mating, so the accuracy is comparable to belt driven systems. Some systems also use a split or dial pinion system to remove backlash.

 

In both belt and gear driven systems, the guidance components usually require regular lubrication.

 

  • Linear Motors

Linear motors are typically the most expensive type of electric linear actuator, and they’re also the fastest and most dynamic.

 

Where an electric motor consists of a rotor inside a stator, a linear motor is a motor unrolled. Because linear motors have lower friction than other devices, some linear motor products can last well over a hundred million cycles, according to Neff of SMAC.

 

When the payload mounting surface is precision-machined steel or granite, the device is called a stage. Across the industry, the term “stage” refers to a higher-accuracy device.

 

Simple Hydraulics vs. Servo Hydraulics

 

According to MachineDesign.com, while intermediate-stroke positioning is possible with simple hydraulics, it requires manual control by an operator. The same goes for speed and force control. For computer-controlled or automated position, speed and force control, servo drives are required.

 

With hydraulic systems, the total footprint of the system is much larger than comparable electric systems. Hydraulic systems require hoses, fittings and valves, as well as a hydraulic power unit (HPU) which has a large footprint. While hydraulic cylinders save space at the cylinder, they more than make up for it with the bloated footprint of their control systems. Servo hydraulics requires even more space, with a control cabinet or PLC.

 

How to Choose the Right Actuator for Your Application

Now that we’ve gone over the basics of the different types of actuators, choosing an actuator all comes down to your specific application. Consider the following questions:

 

Force/Payload

  • High Force – Thousands of Pounds

For extremely high forces, such as a press application or a gantry system for heavy equipment, it comes down to hydraulic or electric. The next question to consider is the cycle rate, to determine which option would wear faster and require more maintenance over the life of your system. Ask your vendor about the maintenance and wear of each product.

 

The next factor to consider is that hydraulic oil is messy. If a spill occurs, cleaning up large volumes of oil can be costly and time consuming. Even if a leak does not occur, oil may creep and slowly film surfaces of your machine. In clean environments such as electronics or food processing, the possibility of oil leakage may eliminate the hydraulic option.

 

  • Medium Force – Tens to Hundreds of Pounds

When your required force is within the range for all three options, consider your positioning needs.

 

Will the motion require more than 2 stop positions? If so, a pneumatic system will be complicated to implement, and require manual adjustment. However, pneumatics may still be the least expensive option. The next question to ask is the level of accuracy required. In assembly tasks, for example, you may require fine-grained accuracy, in the tenth-millimeter range. If so, electric actuators may be the best option. Pneumatic systems are typically accurate to a few millimeters.

 

The last thing to consider is the cycle rate of your application. While linear motors are more expensive than other types of actuators, over many cycles (100 Million+) they keep going strong, while other systems will need replacement.

 

  • Low Force

Consider the accuracy and dynamic motion requirements of your application. As Ed Neff of SMAC says, “dumb” motions, such as a simple push, may require no more than a simple pneumatic cylinder. However, any time you want more control over the position or speed of the device, you should consider electrics.

 

Which Actuator is Best?

When making a decision between electric and fluid-power actuators, the key considerations are positioning accuracy, speed and payload.

 

Fluid power systems excel in traditional applications where the main advantages of electric systems are overkill, making their higher cost unjustified. However, electrics are still developing, with the technology advancing every year. Costs are coming down for even the most advanced electromechanical actuators, and some experts believe that one day fluid power systems will be completely obsolete in the linear motion industry.

 

However, today it’s common to see a mix of technologies, even on one machine. A large press, for example, could use a large hydraulic cylinder, with electric actuators for loading/unloading and pneumatic actuators for gripping parts.

 

If you have any interest in learning more information about actuator motor, please try to check out the site of Hsiang Neng DC Micro Motor Manufacturing Corp. – the company specializes in kinds of DC motors, micro motors, gear motors, etc.

 

Article Source: engineering.com

Transformer Winding Machines: Significance and Types

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Transformer is one of the most crucial components of any electrical circuit. A transformer is basically used to convert (increase or decrease) the voltage, depending upon the maximum allowable voltage of an application. Thus, there are two main types of transformers, namely, step-up and step-down transformers. The main difference between these two types of transformers is the number of windings. Thus, winding becomes the most important part of this electrical device. These windings are manufactured with the help of transformer winding machines.

 

Transformers are used in a wide range of applications varying from a mobile charger to huge industries. Thus, the rating of the transformers can vary from VA to MVA. VA is the voltage and current rating of a transformer. Thus, based on the applications, transformers with different windings are used. There are different types of transformer winding machines used to manufacture transformers with different VA/MVA ratings. Besides this, different types of winding machines are required, depending upon low volume or high volume production. What are these machines? What is the significance of these machines in manufacturing winding? Are you intrigued to know more about them? Read the following post to get a detailed understanding of these machines.

 

What Are the Types of Transformer Winding Machines?

 

As discussed earlier, transformers with different VA ratings require different coil winding machines. Based on this, there are three main types of winding machines used. These three types of machines are as follows:

 

  1. Manual Transformer Winding Machines –

These transformer coil winding machines can either be operated by hand or with the help of a small motor. Transformer coils can be wound precisely by using the manual transformer winding machines. One of the major advantages of these machines is that they are light weight. This makes them portable and can be carried from one place to another easily.

 

  1. Programmable Transformer Winding Machines –

The programmable transformer coil winding machines are an advanced version of winding machines, which feature a 16 Bit microprocessor for smart operation. These machines also have a stepper motor, which is capable of winding up to 750 RPM. In these machines, various functions of a transformer are set-up and programmed. This is one of the biggest advantages of these machines, as programming these functions provides high level of precision in operation. Thus, coils of transformer can be wound easily. Some striking features of this achiness are:

 

  • They have a built-in production counter, which keeps an eye on the number of transformer coil winding.
  • There are a number of menu items, which can be programmed easily.
  • These winding machines are equipped with a speed control knob. This helps adjust the speed.
  • Another important and beneficial feature of these transformer winding machines is that they have a display.

 

  1. Automatic Transformer Winding Machines –

As their name suggests, the automatic transformer winding machines do their job with no or very less need of human interference. The advantage of using these types of winding machines is that they help reduce the labor costs. Various tasks can be fed to these machines, and they are operated using computerized programs. The multi-spindle feature of these machines help to make the equipment multi-coil winding. Multiple coil windings can be done simultaneously using these types of machines.

 

These were the three basic types of transformer winding machines used by a number of manufacturing firms. If you want to get more information about transformer coil winding machine, try to check out the website of DETZO Co., Ltd. – the company specializes in producing fully automated production line and winding machines. Learn more details please do not hesitate to visit DETZO immediately.

 

 

Article Source: https://www.armaturecoil.com/blog/transformer-winding-machines-their-significance-and-types/

Best Ergonomic Computer Desk Chair: Why Do You Need A Right Office Chair?

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Relieve your tired neck and back with smart picks.

 

Why Do You Need A Great Ergonomic Office Task Chair?

 

If there is any one factor that you can change to make spending eight hours a day in an office easier, it’s your chair. There is no shortage of evidence proving that being stuck in a chair for too long can increase the risk of cardiovascular disease and worsen back pain. In fact, sitting too much is even called worse than smoking. Many people who have office jobs develop problems like numbness, spinal misalignment, joint pain, neck pain, and herniated discs — usually from sitting too long on a poor quality chair without support. While you probably do not want to spend a lot of money on a chair, a high quality ergonomic chair is an investment in your health, comfort and productivity.

 

Two separate studies, published in 1990 and 2003, found productivity goes up more than 17% when individuals work in an ergonomic setting with an adjustable chair. The right chair combined with ergonomic training can also reduce workplace injuries. Even if you do not already have wrist or back problems, an ergonomic chair can help you maintain the right posture to avoid strain, carpel tunnel syndrome, lower back pain, and spinal disc injury.

 

The National Institute of Health recommends choosing a chair with all of the necessary adjustments to support proper posture. This includes a chair with casters and a five-point base; a seat pan with dense, small-cell foam padding or coils; a backrest that is either curved or small enough to fit the small of the back; soft armrests with an adjustable height and width; a hydraulic seat heat adjustment feature; and a tilt adjustment to transfer some body weight to the chair’s backrest.

 

Wonderful Fuh Shyan Ergonomic Office Chairs

 

If you work on computer then you definitely need to invest a good ergonomic chair. I think Fuh Shyan’s ergonomic task chairs will be a great choice.

 

Fuh Shyan Co., Ltd. provides many series of ergonomic computer desk chair which can reduce the amount of stress put on your body from incorrect posture. A good ergonomic task chair also keeps you comfortable and focused on your work.

 

Their high quality D Series, T Series and H Series of ergonomic computer desk chairs, hope you can find the right one in your working life. Get more details about ergonomic office chairs, try to visit Fuh Shyan.

SL-T1 Ergonomic Office Task Chair

SL-T1 Model Ergonomic Office Task Chairs. This ergonomic task chair can adjust its armrest, seat depth (slide), seat height, backward strength, and backrest tilt (3 stage). It is with wire control mechanism or T-series mechanism.

Article Source: https://www.omnicoreagency.com/best-ergonomic-office-chairs/

How to Use A Drill Grinder?

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To help you quickly and easily sharpen drill bits, Earth-Chain provides Drill Grinder for customers. Here, I will teach you how to use the drill grinder. Learn how to operate the drill grinder, please check out the steps below:

 

  1. Set Up The Drill To The Collet Holder

Diagram #1 Set Up The Drill to The Collet Holder
Follow up the Steps 1, 2, 3, 4 for set up the drill to the collet holder. (Without tightening) as shown on diagram #1

 

  1. Set Up The Diameter of Drill

Diagram #2 Set Up The Diameter of Drill

  • Turn right the scale annulus to be “0” position.
  • Adjust the scale to meet the diameter of the drill. As shown on diagram #2

 

  1. Set Up The Drill To The Grinding Position

Diagram #3 Set Up The Drill To The Grinding Position
Insert the collet holder with drill and turn right, then tight the drill by collet holder for set up the grinding position. As shown on diagram #3

 

Attn: The scale annulus maybe not exact for the drill diameter, because of used drill or different model of drill anyhow, please always check the center edge of drill must be parallel with the gap of “Collet Holder”. As shown on the right diagram.

 

  1. Grind The Drill Tip

Diagram #4 Grind The Drill Tip

  • Turn on the power of the grinder.
  • Insert the collet holder with drill and push to the grinding wheel slowly, then move left and right repeatedly to sharpen the drill until the grinding sound disappeared.
  • Take out the collet holder with drill and change to the other side to grind again in same way as above mentioned. As shown on diagram #4

 

  1. Center Point Grinding Base Adjusting

Diagram #5 Center Point Grinding Base Adjusting
Adjust the center point grinding base to the suitable position. Turn right for bigger, turn left for smaller. As shown on diagram #5

 

  1. Grind The Center Point of Drill

Diagram #6 Grind The Center Point of Drill

  • Insert the collet holder with drill and push to the grinding wheel slowly, then move left and right repeatedly to grind the center point of drill until the grinding sound disappeared.
  • Take out the collet holder with drill and change to the other side to grind again in same way as above mentioned. As shown on diagram #6

 

Notice:

Please clean the grinding chip often for avoid the chip scrape to the grinding base and keep using life.

 

Earth-Chain drill grinder is guaranteed for one year under normal operating (expendable parts and wheels are exceptions)

 

If you need more information about drill grinders, please do not hesitate to check out Earth-Chain website. And feel free to send inquiries to let them know your requirements.

 

 

Earth-Chain Enterprise Co., Ltd.

No.551, Sec. 1 Gangbu Rd., Wu-Chi, Taichung 43546, Taiwan (R.O.C)

Tel: 886-4-2630-3737

Fax: 886-4-2630-3636

Email: ece@earth-chain.com.tw / www.earth-chain.com.tw

 

What’s The Different Between Agitator Mixer And Reaction Kettle

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Mixer Principle

 

Agitator Mixer is widely used in chemical, paint, food, medicine, building materials, paints, resins, research and other industries. The device may require carbon steel, stainless steel and other materials produced product based on the user’s process, as well as a heating and cooling devices to meet different process and production needs. Heating the form of electric heating jacket, heating coils, the device reasonable structure design, advanced technology, durable, and has simple, easy to use features, is ideal for less investment, faster production and labor saving chemical equipment.

 

Reactor Principle

 

Reactor kettle is a physical or chemical reaction, through the structural design and configuration parameters of the container, to achieve the required heating process, evaporation, cooling and low speed mixed function.

 

What’s The Different?

 

  1. Cover Structure: the reactor head cover as stirred tank cover often flat cap, semi-open, rarely head form.

 

  1. Observe Media Way: the reactor through the mixing of endoscopic observation of the autoclave and the reaction stirred tank through a manhole on a semi-open lid or flat lid observation, much larger than the range of the reactor can be observed in the sight glass.

 

  1. Sealed: Reactor often need to work in a vacuum or under pressure, to install the mechanical seal in order to meet the requirements, then use conventional stirred tank packing can be.

 

  1. Heating Device: reactor requires heating jacket or coil heating and cooling, namely mixing and mixing process is complete the reaction medium at temperatures accompanied by, But agitator usually only as a simple mixing device ,does not require heating process

 

  1. Cost: Agitator mixer is simply than reaction kettle. Can directly reflect in the production costs, so the price of the same size reactor is also higher than a mixer.

 

Above this, the Agitator Mixer is simply structure than reaction kettle and also easy to produce and operation. Both of agitator and reactor can application in liquid materials, and installation method is similar.

 

If you want to get more information about Agitator Mixer, please do not hesitate to check out the website of King Spark. The company specializes in kinds of hand tools including air sander, air spray gun, pressure tank, air wrench, etc. Get further details, welcome to visit King Spark immediately.

 

 

Article Source: https://www.linkedin.com/pulse/learn-whats-different-between-mixer-agitator-reaction-catherine-zhao

Keep Your Screen Changer In the Flow

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The screen changer plays an essential role in generating quality extrudate. Here’s what you need to know to keep it functioning properly.

 

There are many different designs of screen changers on the market today, from manual slide plates to constant-pressure and continuous backflush or scrapper designs, and each one comes with its own set of strengths and weaknesses. As a processor, you need to know these in order to make the best choice of screen changer for your particular application.

 

This article will focus more on general process troubleshooting as opposed to machine-specific issues, but it’s important to note that a large percentage of problems that extrusion processors have with their screen changers occur because the screen changer they’re using is not the best design for their application. Each specific extrusion filtration application should be closely examined prior to specifying a screen changer for the project.

 

FILTRATION MESH

Every processor wants the best filtration they can get for the area of filtration they have. Very few, however, utilize a screen-pack configuration fully optimized for their process. Take as an example a situation in which an operator is attempting to extend a production run between screen changes. As the screen becomes occluded, head pressure rises and eventually causes the wire cloth to fail. A simple operator solution is to pile on additional 20-mesh screens for increased strength.

 

A better solution would be to increase the support strength of the base screen, using a heavier-gauge 10-mesh screen layered with a single 20-mesh screen. The 10- and 20- mesh screens will support each other by working at two levels. The end result is the ability to run longer between changes, but without the unnecessarily high pressure drop and resulting increase in shear heat. Any increase in pressure-induced shear is best avoided, since this will generate higher melt temperature at the discharge end of the extruder, creating a higher demand on downstream cooling capacity and potentially reducing output.

 

Most screen-changer suppliers offer process-support services that include pressure-drop calculations. These are simple to perform and factor in material viscosities, breaker-plate open area, and screen open area to arrive at the best screen-pack configuration for the process and operating environment. This service is normally a free and simple means to optimize polymer flow performance.

 

TEMPERATURE CONTROL

Another issue occasionally attributed to screen changers is temperature fluctuation. Best practice is to stay alert to gauges, heaters, and heater circuits. Monitoring these on the screen changer may not be as critical as checking the extruder and feed screw, but it can help spot an issue before it becomes catastrophic.

 

Another tip is to optimize the number of heat zones necessary to balance temperature across the screen changer. More specifically:

 

  • Hydraulic slide-plate screen changers are best served by three zones—a body zone and independent zones for the each end of the slide plate. Many processors wire these machines into a single control zone, resulting in too much or too little heat to the slide plate. This can destabilize the melt profile and cause material burning in the off-line breaker plate.

 

  • Continuous bolt-type screen changers are normally best served by a single control zone, but as these machines increase in size, additional body zones help balance the heat. Bolt-type continuous screen changers heat the bolts by conduction from the body. If heat is unbalanced, the body can shrink onto the bolt and generate high enough clamping forces to prevent movement of the bolt.

 

  • Machine adapters are also normally best served with independent heat control. This, however, will vary with size.

 

PRESSURE FLUCTUATION

Streamlining the polymer flow through the screen changer will also affect process stability. For sensitive materials or those with unique flow characteristics, CFD (computational fluid dynamics) modeling software can be utilized to optimize screen-changer flow passages and minimize material residence time. Along this line, adapter length, steps and transitions, and polymer inventory between the screw tip and screen pack can be critical to establishing best flow while minimizing polymer degradation points and thermal stratification.

 

Vent cycles on continuous screen changers can influence pressure stability. Most bolt-type screen changers can see up to 50% of the available filter area removed from the process for screen change. While this naturally causes a rise in head pressure, the flow rate and die pressure normally remain relatively stable. The issue arises with the reintroduction of the clean screen. Vents machined into the bolts divert a small portion of the polymer melt to prefill and purge air from the incoming screen pocket. The resulting slight drop in die pressure can be minimized by operator finesse or more precisely by PLC control. Constant-pressure screen changers, such as rotary wheel designs, are not normally subject to these issues. One auxiliary that can help tremendously with fluctuating pressure is a gear pump, which can tolerate upstream pressure swings while holding the die pressure stable.

 

LEAKAGE

Leakage is a problem with almost all screen changer designs as they age, but most noticeably with slide-plate models. This type of screen changer relies on manually adjusted or pressure-activated seals and is subject to wear and tear from the movement of the slide plate, degradation of the seal-pressure ring, and damage from dislodged screens. Seal maintenance for these machines can be required as often as weekly to once a year. Maintenance can lead to tear down and reassembly, which can be a time-consuming, expensive process. Even before it reaches this point, the housekeeping required keeping the slide plate clean and preventing polymer from leaking onto wiring and other equipment is significant.

 

One way to minimize leakage on a system like this is to increase the head pressure. Your intuition might tell you lower pressure would be better because it would put less strain on the system. However, because the seals are designed to respond to pressure in the extruder, they are only working at their peak when the pressure is higher. At a lower pressure, the seals will relax slightly. When the extruder is idle or running at drool speed and there is very little pressure being exerted on the seal, it becomes easy for lower viscosity material to leak out. One newer slide-plate seal, an all-steel, segmented pressure-ring design, addresses these problems and caries a lifetime leak-free warranty regardless of temperature and low viscosity, making this seal the first to operate leak-free on high-temperature coating applications.

 

Material leakage on bolt-type or other close-tolerance rotary wheel machines that operate without a mechanical seal can likewise occur over time; but with these designs, leakage is almost always caused by mechanical damage. These precision-machined screen changers are typically designed for a fairly narrow material viscosity range.

 

As such, you should not apply a machine designed with clearances for high pressure and high viscosity to a low-viscosity process without approval or modification from the supplier.

 

RESIN CONTAMINATION, DEGRADATION

The primary purpose of a screen changer is to filter out contaminants from the melt stream; but the fact is, screen changes almost inevitably introduce contaminants, some of which get into the die. These result from imperfect cleaning of the slide plate, bolt, or wheel. For example:

 

  • This can occur on a slide-plate screen changer as the upstream and downstream seals scrape material residue into both sides of the oncoming screen pocket. Upstream contaminants are caught on the screen. Downstream contaminants flush out into the die.

 

  • A continuous or constant-pressure screen changer can experience this as well, but to a much smaller degree. The gap between the bolt or wheel and housing is measured in microns on the downstream side. The rare contaminant that makes it through this clearance to enter the melt flow is only consequential to the most demanding of applications, and for these few occasions, secondary, long-life canister filters will catch anything that comes through.

 

Many processes do not have to run continuously or require 100% quality and can overlook contaminants during screen change. However, if your customer has zero tolerance, you’ll need a different kind of screen changer. There is no way to continue using a slide-plate screen changer without introducing some level of contaminants or material degradation from the offline breaker plate. To solve this, a continuous bolt-type or rotary-wheel screen changer is a better solution.

 

LOCK-UP

Continuous screen changers that use no mechanical seal utilize precisely machined clearances to affect a polymer seal. These same clearances provide lubrication between the bolts or wheel and housing and must be maintained to avoid locking up the machines. Lock-up (jammed bolt or wheel) can be a result of various things, usually preventable with correct operator usage. The leading cause of lock-ups occurs when the bolts or wheel are not cleaned and lubricated regularly.

 

Many processors with a bolt-type or rotary-wheel screen changer have bought these continuous-process machines because they have no mechanical seals and run reliably and leak-free for years on end. While these advanced designs certainly require less upkeep than a slide plate, maintenance during screen change should not be neglected.

 

Over time, excess buildup of polymer can plate onto the bolt or wheel surfaces, reducing required clearances and eventually requiring more hydraulic pressure to shift than is available from the power unit or mechanical drive.

 

This stuck bolt or wheel is easily preventable with regular cleaning. A lock-up requires a shutdown and reheat process that can take up to 8 hr or more. Doing daily maintenance and cleaning of the piston takes 5 to 10 min and can save a considerable amount of downtime. “The biggest issue is getting into the mindset of cleaning the whole bolt,” says Marty Danco of Verity Resins, a recycler and compounder based in Forest City, N.C. “When you lock it up, there’s no way home, it’s locked up for good. Using proper copper gauze, the bolt should be cleaned every day—not just the top, but underneath it and on the sides.”

 

The necessity of regular maintenance also holds for breaker plates. Over time, material will carbonize on them, closing off the holes, which raises head pressure and eventually compromises output. Breaker-plate clogging is also easily preventable. The best solution is to make sure to have a clean spare. Swapping these breaker plates out even once a week is great preventive maintenance to ensure it never reaches the point where the process or the final product is impacted.

 

Most leading screen-changer suppliers are excellent resources to refer your troubleshooting issues to. Doing so, instead of relying solely on your maintenance crew, can often reduce your downtime and repair expenses, eliminate some problems before they occur, and potentially point you to a better process solution than the machine currently in service.

 

If you need more information about plastic extruder screen changer, please do not hesitate to check out the website of Hsin-Long Thread Rolling Machine Co., Ltd. – the company provides kinds of blown film extrusion machines, die head, air ring, bubble cage, etc. Learn further details, please feel free to send inquiry to Hsin Long.

 

Article Source: Plastics Technology

What are Kayak Scupper Plugs: How and Why You Should Use Them

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If you’re planning your next kayaking adventure, you should be prepared for the challenge. That means having appropriate equipment at your side. Kayak scupper plugs fall into this category, as well. If you haven’t used kayak scupper plugs until now, our article will serve as an informative guide on the topic.

 

Introducing Scupper Holes

To start with, sit-on-top kayaks are equipped with scupper holes. You may find them in the foot walls, cockpit, and tank well of your kayak.

 

Essentially, the holes aim at draining away the water from the kayak. Especially when the load becomes heavy. They also have the purpose of supporting the deck, as the kayaker sits on top of it.

 

While this feature can come in handy, it is linked to an evident inconvenience: it might get everything in the kayak wet.

 

The good news is that you may block the scupper holes by using kayak scupper plugs.

 

What Is the Purpose of Scupper Plugs?

For the most part, their primary objective is to maximize your safety and comfort, keeping the water out of your kayak – we know how annoying that can be.

 

Simply put, having a set of reliable scupper plugs will prevent you from sitting in a puddle. Or, in worst case scenario, it will deter the kayak from becoming a bathtub overflowing with water.

 

So, scupper plugs are specifically created to fit in those holes. Perhaps this didn’t occur to you until now. Nevertheless, it might happen, especially in choppy waters.

 

The second purpose of scupper plugs is to increase the rigidity of the hull.

 

Should There Be Any Water in My Kayak?

If you have used scupper plugs, and some water still managed to enter your kayak, you needn’t worry. The fact that there’s a bit of incoming water in your kayak doesn’t necessarily mean you’ll sink.

 

Irrespective of the kayak’s capacity and the scupper plug specifications, some water will inevitably enter your kayak – one way or another. Nevertheless, there’s a crucial distinction between abundant water and a relatively low level of water.

 

The bottom line is that having excessive water in your kayak is quite problematic. Therefore, you should avoid that, as much as you can.

 

At the same time, to get excellent results and keep the water at a distance, you should place the scupper plugs tightly. The harder you plug them in, the more airtight they will be. This way, you minimize the likelihood of sitting in a pool of water.

 

Are Scupper Plugs Necessary or Not?

Scupper plugs definitely come in handy. They do an excellent job at maintaining the kayaks dry, significantly reducing the amount of water in it. We find them to be specifically useful during long boat rides.

 

For instance, if you plan on paddling in calm waters with no waves whatsoever, the scupper plugs might even keep your kayak dry.

 

Conclusion

So, what are kayak scupper plugs?

 

In short, they’re a tool to help you keep water out of your kayak, all in an effort to make your ride more enjoyable.

 

If you need more information about Kayak Scupper Plugs and more Kayak Deck Hardware, please try to visit BroadPlast Industrial Co. – they are the professional manufacturer of kayak accessories. Get more details, welcome to check out the website of BroadPlast immediately.

 

 

Article Source: Riverratguide.com

How to Choose The Correct Caster Wheels for Your Floor?

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Carpet Means HARD Wheels!

Picking the right caster wheel material for your type of floor is very important. Casters with Hard Wheels will slide on a hard floor like ceramic tile or hard wood. When they slide, they can scratch the wood and on tile the wheels can actually be “sanded” down they slide over the grout lines. This leaves bits of black plastic on the floor. Hard wheel casters work well directly on carpet. For short pile carpet, a 2″ or 50mm wheel will work fine. For deeper pile, a larger wheel of 60mm or 75mm is needed. If the pile and padding is very deep, use a floor mat; a Floor Mat is HARD and needs Soft Wheels.

 

Tile and Wood means SOFT Wheels!

Casters with Soft Wheels can get “traction” on a hard surface. Just like the rubber tires on your car, caster wheels will have some sort of soft material applied to a wheel. When a wheel is rolling on a hard floor, it cannot scratch the floor. Hard floors can get damaged even with soft wheels. If the floors are dirty and grit or sand becomes embedded into the tire, it can scratch the floor. If the wood used on the floor is soft, it is possible that the wheel could “dent” the wood. We will not “recommend” any type of caster for a wood floor.

 

We can tell you that the “softest wheel” will work the best. A good rule of thumb is that if you have a wood floor, find out what the Janka Rating is for the floor. If the Janka rating is higher than 1290 (the hardness of solid Red Oak), you should be able to use soft PU caster wheels. If it is softer than that, you must use a soft rubber.

 

Watch the CAPACITY of The Casters!

Casters are rated by how much weight they can hold. That doesn’t mean that they will roll well with that much weight as there are many factors that affect how it rolls.

 

Too much weight on a caster with a small capacity is not safe. Under normal conditions, when you figure capacities, you multiply the capacity of each caster times the number of casters used. This will give you the maximum weight that can be held by this set of casters. This is true for furniture as long as the weight is equally distributed but if it is not, add more casters to the heavy end to try to balance the load.

 

Chairs are another issue with capacity. When you sit in a chair and don’t move, your weight is fairly balanced on the casters. As you try to roll, you shift your weight and now some of the casters are carrying more weight. The worst part is when you lean back or lean forward. It is possible that ALL of your weight is transferred to the front 2 casters instead of 5. The maximum capacity for chairs should never be more than 3/4 of the total capacity of all the casters. Please think safety when putting casters on a chair.

 

If you have any interest in caster wheels, try to visit the professional caster wheel manufacturer, ENJOYING GO Co., Ltd. – the company provides chair casters, furniture casters, compression casters, PU caster, etc. Get more information, welcome to send inquiry or contact them right away.

 

Article Source: http://www.needcasters.com/how-to-choose-casters-for-hard-floors-or-carpet.htm

What are Electronic Deadbolt Locks?

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Having a safe and secure door lock is the first step toward ensuring safety of the residence. For decades, this work was done by the simple key and locks.

 

However, these locks could be easily damaged and instances of break in increased. Looking for the appropriate solution to this problem, spring bolt lock came into use.

 

These locks consist of spring loaded bolt with an angled edge. When the door is completely closed, the spring engages and latch bolt holds the door closed. However, with time the use of deadbolt came into existence.

 

These locks are more convenient to use than the spring bolt locks. A typical deadbolt lock is handled manually and requires turning a cylindrical knob so as to open the door. Such deadbolts can have single cylinder requiring one key or double cylinder requiring two keys.

 

However, the problem with a simple deadbolt lock is that it requires a key. Most of the times, a person may forget the key. Besides, these simple deadbolts were inefficient to be used in massive buildings which require a large number of locks. Hence, an improvement was made in the deadbolts which now operated electronically without needing any manual effort.

 

Such deadbolts are called electronic deadbolt locks. In rest of the article, we would be discussing the various aspects of using an electronic deadbolt locks.

 

Electronic Deadbolt Lock

Electronic locks have become one of the most popular security locks used for doors in both commercial and residential buildings. Unlike simple deadbolt locks, these locks do not require keys for operation.

 

The actions of these locks are more accurate. Moreover, these locks do not allow easy break in into the building. Thus, the locks are widely used in hospitals, corporate offices, defense centers and private buildings. To open a lock, one need to feed a combination of codes which the related electric circuits analyses.

 

These code combinations can be fed either using cards or keypad. In most of the commercial and govt. buildings, cards are widely used.

 

How Does Such Lock Work?

The lock contains an electric circuit. The lock has knob on both sides of the door. The electronic circuit is arranged to read the input code. Once input code is fed, the circuit reads the code and matches it with the stored code. If the two matches, then, electrical operated bolt is activated and consequently the door is unlocked.

 

A battery is used to supply power for the circuit operation. The lock uses the solenoid or electric motor to activate the bolt mechanism.

 

Benefits of Deadbolt Locks

The electronic deadbolt locks have a numerous of advantages over the rest of the traditional deadbolt locks. Some of them are enlisted below:

 

  • Unlike simple deadbolt locks, the electronic deadbolt locks come with the patented digital technologies.
  • These locks are equipped with both key and electronic locking mechanism.
  • Multiples code combination can be stored which can allow several layers of security to the building.

 

Limitation of Deadbolt Locks

Despite of having brilliant features, there exist some factors which a cautious user must consider. Here, we enlist some of the limitations faced by the electronic deadbolt locks.

 

  • These locks are operated through solenoid or electric motors, thus, they need a large amount of power for effective functioning. However, the use of batteries has helped to solve this problem up to an extent.
  • If not installed properly, the cylindrical knob can be a hazard instead of providing safety to home.
  • The codes if guessed by someone else (other than the resident) can lead to awkward situation.

 

Features of A Good Deadbolt

There is a large number of electronic deadbolt locks available in the market. Thus, it is primary important for a buyer to judiciously choose the appropriate product for ensuring the home safety. In this regard, we present below some of the features which a good lock should possess. Hope that the buyers shall find it helpful before they go out for purchasing a new product.

 

  • The installation of the electronic deadbolt lock should be simple and inexpensive requiring minimum alteration to the premises.
  • The lock should have the capability of storing more than one combination so that different person can have the entry (with prior knowledge of the resident) without knowing the actual combination used by the resident of the house.
  • The lock should be capable of having the number of digits as combination according to the choice of the residents. That means the lock should not restrict the resident from choosing any combination as per his wish.
  • It is advisable to buy a double cylinder electronic deadbolt lock installed with glass windows.
  • A good electronic deadbolt lock should be battery operated.
  • It should use both card and keypad number for feeding the combination code.

 

Summary

The electronic deadbolt locks have rejuvenated the security issues concerning a residential or industrial building. The locks most popularly used in industrial buildings have enabled to gear up the best security measures.

 

Besides, the locks are being extensively used in buildings having strategic significance. These locks ensure null break in and are most convenient to use. There is no need for key as the locks are electric automated. Moreover, the locks also have the feature of storing more than one security code.

 

This unique feature adds to the security level of the building. However, one has to carefully choose the appropriate security code so that it is not easily guessed by someone else. With the use of such locks, one can surely enjoy the utmost security and safety level.

 

If you have any interest in electric deadbolt, welcome to check out Pongee’s website. The company specializes in kinds of access controllers, time attendances, EM locks, etc. Learn more information please feel free to send inquiry to Pongee.

 

Article Source: ReviewsWorthy