Which valves can you use?


Pneumatic conveying valves for sale

There are many types of pneumatic conveying valves, and a system can have many types installed, depending on requirements. On the market, for each of them, there are different manufacturers with different technical solutions. These products are modified from season to season in order to achieve better and better results. Our company markets and sells all varieties of valves for pneumatic conveying systems and can advise you on the best solutions available.
The must-have valve is the rotary valve, or rotary star valve, or rotocell, or rotovalve. It is used to feed pneumatic conveying lines, for dosing materials and for unloading filters or vacuum machines. The other types of valves are generally used to isolate or divert the air flow, the material, the exhaust and the vent.

Rotary valves or rotovalves

They are probably the most widely used devices for feeding material into a pneumatic conveying system working through gravity. Rotary valves are essential for feeding or discharging powdery or granular products in a controlled manner from two different pressure chambers such as silos, hoppers, bag filters, cyclones, mixers or screw conveyors. Schematically, they consist of three main elements:


The external body or box, made by casting or custom-assembled. It can be made of cast iron, carbon steel, stainless steel or wear-resistant material. Depending on the use, we also sell star valves with a ceramic-coated or chrome-plated interior. The coupling flange can be square, rectangular, circular or ellipsoidal.


The internal rotor consists of a number of vanes or blades, mounted on a rotating shaft, made of different materials and with various construction solutions depending on the application. For example, rotors can have opened or closed extremities: in the first case all the blades will be welded only to the shaft, in the second case to the shaft and two discs at the ends. Closed rotors are more suitable in high working pressure systems, more abrasive materials and when air leakage must be kept to a minimum.

The section of the rotor shaft with attached blades also has different conformations for different industrial needs. Generally speaking, this section can be seen as a number of contiguous chambers in the shape of a V letter, each one with a joint apex on the shaft. For very compact materials, however, U-shaped chambers are more suitable, so that the material is discharged more easily and does not stick to the shaft.

Finally, we also have in our catalogue rotary valves with adjustable blade ends (bibs) and made of specific materials, which can provide greater elasticity, greater flexibility, great resistance to abrasion or be spark-proof.


The motor to rotate the shaft is positioned in a way that reduces space requirements and facilitates maintenance. The geared motor can be mounted directly on the rotor shaft, or connected with a coupling or chain drive. Models are also available with a variable speed drive or without motorization, the so-called bare-shaft rotary valves.

The material is stored in the upper container, which is connected to the rotary star valve through the inlet opening, and continuously fills the chambers shaped by the vanes on the rotor. The rotating shaft leads the material to be discharged through the lower outlet opening into the conveyor line. Improvements in construction materials and construction methods made rotocells much more effective at high pressures, working at large pressure differentials and reducing air leakage. Rotovalves are also available:

  • in ATEX version
  • with teflon, nickel and chrome plating treatments
  • with lubricated, air-flushed, gas-flushed and high temperature seals
  • with rotation indicators
  • with motorisation servo-ventilation
  • rapid disassembly
  • rapid disassembly with extraction device (rotating; both sides; with guide)
  • wear-resistant geometry

Design modifications made it possible to obtain star valves suitable for a wider range of substances. Varying the angle of the inlet opening, the result is that the material does not completely fill the roller chambers, so that the material can move more freely and is not subjected to forces that tend to deform it.

This type of valve is therefore widely used, for example, for plastic pellets. We are also thinking of fluidizing valves, where the air flow is allowed to pass through the rotary mechanism, so that it can contribute to chambers emptying. This type of valve is suitable for particularly cohesive materials.


  • Case heated by steam or oil
  • Collector for gas leakages
  • Electronic device for monitoring the rotor-case contact
  • Pneumatic socket
  • Speed detector
  • Separator to separate the product from the drawing gas flow
  • Flushing system

Exhaust valves

These valves are used to stop the air flow and the material; they are designed for on-off use and not for flow control purposes. When the valve is open, material and air must be able to flow freely and regularly through it. If the valve in the open position exposes its surface to the flow, as happens with ball and clamp valves, this must be done in a professional manner. Even small surface irregularities or protuberances can lead to increased turbulence and a rapid deterioration in performance. This is obviously more true when the material transported by the system has highly abrasive characteristics.

These valves are also particularly vulnerable during the opening and closing sequences, which should be completed in the shortest possible time. Apply proposes, in addition to ball and clamp valves, a new type of unloader valve which, when the valve is open, has the moving parts outside the flow carrying the material. When closed, the valve first stops the flow of material and then becomes airtight thanks to an inflatable seal. The valve can be water-cooled and can therefore handle hot materials.

Insulating valves

Valve model mainly used when material has to be transferred in plug mode, with material “batches” and air “spaces” alternating along the system pipeline. These valves must guarantee a tight seal and withstand the pressures that are applied from time to time.

Apply distributes butterfly, disc and guillotine isolating valves. The butterfly valve is the optimal solution for non-abrasive materials, is relatively inexpensive, requires little space, is not heavy and has good sealing properties: all qualities that made it popular, especially in food industry. To handle wider ranges of materials there is the disc valve, which requires little space and has the moving parts outside the flow. Also worth to mentioning are the guillotine valves which, although they were the first to be offered on the market, retain the considerable advantages of being cheap, easy and quick to apply and requiring little space. These characteristics make them invaluable as support valves when more complex and time-consuming valves have to be replaced.


Breather valves

They may seem like unimportant valves, but if you think of a pneumatic conveying system that is handling ash or concrete, involving high pressures, you will realize that relief valves can operate in quite extreme environments. With high pressure vents the air velocities that these valves withstand can be very high, albeit for limited periods of time.

In presence of abrasive dust, even in discrete quantities,  the most suitable valves are, for example, pinch valves; if the material is not abrasive, we can also supply diaphragm valves.

Flow diverter valves

Diverting flow is such a common need in pneumatic conveying systems that we can offer a wide range of choices. For example Apply can sell you valves specially designed for this purpose, or provide you with a set of isolating valves that perform exactly the same function. The most common diversion case is to direct the flow on one or two alternative routes, typically to sections leading to material discharge into one or more silos or hoppers. In this situation the main conveying line must have a diversion mechanism for each pipe branch.

Diverter valves can be divided into two broad categories. In the first category hinged bulkheads are placed at outlet pipes discharge points. By acting on one or the other it is possible to decide where to direct the flow. Hinged bulkheads are sealed, while the inside of the pipes are lined with urethane or similar material to provide a better seal. This solution has the advantage of being very compact and light. In the second category, the valve has two or more tunnels inside, which are oriented between the inlet and the outlet where the flow is directed. This solution guarantees greater tightness, but is less suitable for more abrasive materials.

Flow divider valves

The division of the main flow into two or more branch flows is not a frequent request in the field of pneumatic conveying. For this reason, there are only a few valves available on the market that are specialized for a particular area. For example, you can buy flow divider valves from us for pneumatic conveying systems supplying boilers or blast furnaces, where it is necessary to feed the combustible material from a number of points distributed around the circumference of the plant.

The main requirement in these cases is that the material flow from all points must be uniform, despite the fact that they are located at different distances from the main transport line. This division is achieved in an optimized manner in the vertical level, with adequately dimensioned supply lines to balance the amount of material arriving in the time unit.