It is a compact mechanical device for continuously discharging bulk powders or granules under gravity flow. By definition it is the simplest of machines having only one moving part (ignoring the drive); a multi-vane rotor revolving in close contact in the housing and where the housing has an inlet at the top, and an outlet at the bottom.

Generally speaking, yes. The terms are usually used universally. They are also sometimes called rotary airlock valves or rotary valves. Do note, though, that not every rotary valve or rotary feeder is necessarily an airlock valve.

We wouldn’t want to give an answer of yes here. Like many precision parts, rotary airlock valves should only be purchased from trusted manufacturers who are compliant with industry standards and have a proven track record of quality and customer service. The importance of using well-made valves cannot be understated. Be discerning and do not settle for less than top-notch products.

There are two most common reasons rotary valves fail or cease to work efficiently is bearing failure and seal failure. The valves themselves are often in good working order, but blown seals and/or bearings can cause malfunction and even all-out failure. The good news is that bearings and seals can be replaced without replacing the whole valve. If you are burning through seals and bearings, talk to an expert about how you might benefit from upgrading.

I would give the answer of yes. Sometimes, your existing valve can be re-manufactured and restored to new condition. This is a great option, since it can save you money. It is also nice if your valve happens to be a discontinued or difficult to find model. If a valve is beyond repair, a good machine shop may be able to fabricate a new one to fit your existing ductwork.

A vented surge hopper is typically the most effective way to take care of an air leak. The hopper serves as an intermediary between the storage vessel and the conveyance system, forcing excess air through a vent filter. A surge hopper can also be used in conjunction with a secondary airlock valve, allowing several additional feeding and metering options. There are many ways to address leakages and help with air management issues. It is always advisable to talk to an expert about which solution would be best for your situation.

Many of our rotary valves can last a lifetime especially if using our back-up services. We would recommend that customers have maintenance regime to clean and service their rotary valves, which will help to prolong life. To help with this at Taiwan Control Valve, we hold stocks of spares that are readily available to order. If we do not have it in stock, we can manufacture to order.

Rotary valve is applied in the chemical, pharmaceutical, plastic, food, agriculture minerals, textiles and other related industries.

  Air leakage will occur in every rotary valve. There are three main areas where air leakage will be present in a rotary valve. The first and most obvious place that air leakage will occur in a rotary valve is within the empty pockets as they return to the inlet. The second and third areas on a rotary valve where leakage can occur are the clearance between the housing and the rotor vanes. This can happen between the top sides of the vane (radially) or on the sides of the vanes between the end covers (axially). The rotor vane tip tolerances are very important to the valve function. We will discuss this further later in the article.
    
  Air leakage can happen in a positive pressure system or a vacuum system. In a positive pressure system, the air leaks across the valve and this loss of air cannot be used for conveying the product. Therefore, a larger blower package will be needed to move the dry material fed by the rotary valve into the conveying line. Also, the amount of air leaking across the valve can affect the efficiency at which the product throughput rate is discharged from the valve. Therefore, the sizing of the blower package becomes extremely important. In order to ensure that the valve will be working efficiently and the blower package is sized correctly, you can ask your rotary valve manufacturer for an air leakage rate for the valve they are providing.
     
  Vacuum conveying or negative pressure systems are not immune to issues with air leakage as well. For example, if you have a vacuum receiver with a rotary airlock and the valve is discharging the product into a drum, there is a potential for air leakage from the ambient air on the discharge side of the valve. The air could go up through the rotary valve and enter the vacuum receiver. Once this happens, the vacuum can now pull too much air and enter the system. This will affect the product being pulled over by the vacuum and could cause problem for the entire system.