This website is operated by one or more companies owned by Informa PLC, and all copyrights belong to them. The registered office of Informa PLC is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.
The rotary air gate valve is a key component of the material process. It is generally considered that the valve is just a valve that can be used in any number of different material handling systems. All types of valves include the same basic components: a valve body with an inlet and an outlet, two end plates, and a rotor with blades. During operation, the shaft is driven to rotate by a motor and a chain. When the blade rotates, a certain volume of material enters the pocket of the rotor through the valve inlet, and then moves to the valve outlet.
According to the characteristics of the material to be processed, the valve has a variety of configurations. Most manufacturers provide valves with round, square or rectangular inlets. The valve body is usually made of cast iron, cast aluminum or cast stainless steel, and can have a special coating for grinding products or a highly polished finish for the food and dairy industry. The rotor can be open or closed, with at least six blades, and can be fixed blades, or steel and flexible tips, depending on the application. Rotary air gate valve types include straight-through, blow-through and side inlet â????? Each has its own advantages and is suitable for various applications.
The rotary air gate valve is designed to be used as an air lock, a metering device, or both. They are designed to minimize air leakage while allowing materials to pass between different devices under different pressures. The valve also acts as a metering device that will operate under the head load of the material and adjust the flow of the material at the required rate between equipment with the same pressure.
Although it is a simple valve, all parts are precision machined to form a tight, minimal operating gap between the rotor and the housing. These tight tolerances are usually 0.004 to 0.006 inches, which is the average thickness of human hair. What are these small gaps creating the “???? airlock”???? Because they minimize air leakage between the inlet and outlet flanges and still allow material to pass through the valve. From the dust collection system to the vacuum receiver to the dilution pressure delivery system, the rotary air gate valve allows the transfer of materials with minimal air loss and allows the process to run continuously.
In this article, I will focus on the causes of the clogging of the rotary airlock and how to prevent it, and discuss the options for handling products with larger particles (hard materials such as fibrous materials or plastic particles), where the product shear and Clogged valves are a major problem.
As mentioned earlier, most rotary airlock valves have strict tolerances between the rotor and the valve body shell, so when dealing with dust, powder and small particles, the product passes through the traditional straight-through rotary airlock without any problems. Shearing and clogging occurs when large, hard particles are introduced and sandwiched between the rotating rotor blades as they enter the casing. This squeezing action can cause vibrations, screams, and even jams, and cause damage to the product. Clogging may also occur when the valve size is too small. For example, a 3 inches. The lump cannot pass 6 inches. Valve, because the mass is larger than the size of the rotor cavity in the valve.
If you encounter a paper jam during operation, please refer to the manufacturer’s operation and maintenance manual and check for such common problems. Here are some questions to ask:
It is also possible that interference may occur months or even years after commissioning. Are there any changes to the process-for example receiving materials from different suppliers (which may have different characteristics such as moisture content) or the beginning of cold weather for outdoor installations? Other possible blockages may be due to foreign objects entering the process, such as wrenches or welding rods, or even garbage mixed in by suppliers.
Depending on your process, there are several ways to reduce the potential problem of valve clogging. Using a traditional straight-through valve, you can install the tip of a flexible rubber material to an adjustable rotor (such as polyurethane or Teflon) in mechanical conveying applications, or install an inlet shear deflector installed at the inlet of a rotary airlock to make Material to avoid contact between the rotor blades and the valve inlet. Another option is to meter the product into the rotary airlock so that the bag is only partially filled, so that the rotary airlock minimizes air leakage, but no longer acts as a metering device. Â
The best solution to prevent shearing and clogging is a side-entry rotary air lock, which is specifically designed to overcome this squeezing problem, and is also designed for positive pressure and vacuum/suction pneumatic conveying systems. The valve name comes from the inlet throat, which is completely off-center, allowing product to enter the side of the rotor instead of the top. With a side entry throat design, the product is captured by the rising of the rotor blades, which keeps the product away from the shearing point. This also reduces pocket filling, which reduces the possibility of product shearing. The entrance throat also has a?????V???? The shape of the rotor entering the housing, minimizing pinch points and helping to push the product away. The design of this valve reduces the shear force of the product and reduces the possibility of impact load, which may cause damage to the drive components. The valve is very suitable for the plastics industry, whether it is processing raw plastic particles or recycled materials in the recycling industry. It can also be used to handle larger, fragile particles to minimize the fear of shearing for product damage.
If you have any process concerns regarding possible product clogging, please contact your valve manufacturer to ensure that you have installed the correct rotary air gate valve for your process. Common questions they should ask include the product being processed, bulk density, particle size distribution, whether the product is fragile, maximum temperature, pressure difference, discharge rate, and system layout. Depending on the product and particle size, small samples may be required for evaluation, or large samples may be required for testing. With the correct application information, valve type, and design choices, most (if not all) jamming, shearing, and noise problems can be overcome.
Paul Golden is a sales manager for Carolina Conveying Inc. (Canton, North Carolina). For more information, please call 828-235-1005 or visit carolinaconveying.com.
Post time: Aug-16-2021
