What Is Pneumatic Accessories?

Pneumatic accessories are industrial equipment used to realize industrial automation. There are positioners, limit switches, pneumatic reversing valves, air filters, etc. for your choice. Each pneumatic accessory has a different function. It is generally used with various types of pneumatic valves, which is convenient for remote control and industrial automation to improve the production efficiency of the project.



A positioner is an industrial device that receives or feeds back signals and delivers air to a pneumatic actuator to adjust valve opening and closing.
● Responsive and precise adjustment
● Available in single-acting types and double-acting types
● Explosion-proof type is available for the dangerous applications
● Helping you control the valve remotely

Limit Switch

The limit switch is an industrial device that feedbacks the opening and closing of the valve body. At the same time, it can feedback signals to the system, so that you can know the status of the valve by checking the system.
● Clear viewing window for easy observation of valve opening and closing
● IP67 protection grade can be used normally outdoors
● Explosion-proof type is available for the applications required.

Pneumatic Reversing Valve

Pneumatic reversing valve is an industrial equipment controlled by electromagnetic. Mainly used to control fluid automation basic components, and to control the opening and closing of pneumatic valves. The action is accurate, the degree of automation is high, and the work is stable and reliable.

Air Filter

An air filter is a filter used to filter impurities in the air so that clean air can be the driving source. In order to make the pneumatic valve run more smoothly and have a longer working life.

The above is the introduction of the pneumatic accessories provided by COVNA. If you have a demand for a complete set of pneumatic valves, you are welcome to consult us to obtain the optimal valve solution and cost budget.

COVNA Actuator Valves For Mechanical Vapor Recompression

Mechanical vapor recompression is an industrial system for seawater desalination, metal processing plants, and food processing plants. It is used for waste & wastewater treatment, improving water resource utilization and waste treatment rate, and making our living environment more environmentally friendly. Since 2000, COVNA helped more than 500 wastewater treatment projects with automated valve solutions. In this article, we will recommend actuator valves for mechanical vapor recompression based on our knowledge of the product and our knowledge of wastewater treatment projects.

Since the medium of wastewater treatment projects will contain a certain degree of corrosiveness, we will recommend stainless steel valves or fluorine-lined valves to customers.

Stainless Steel Valve

The valve body and ball/disc are made of stainless steel 304/316/316L and can withstand media from pH 1 to 14. Provide you with corrosion-resistant fluid solutions.

Stainless steel valves can be divided into stainless steel ball valves, stainless steel butterfly valves, stainless steel gate valves and stainless steel globe valves for your choice.


Fluorine-lined Valves

The valve body is cast steel. The ball/valve plate and seals are all PTFE, and the seals will be thickened. PTFE has excellent corrosion protection properties, making it ideal for regulating flows containing aggressive media.
Fluorine-lined valves can be divided into fluorine-lined ball valves and fluorine-lined butterfly valves.

The pipelines of wastewater treatment projects are divided into different levels of areas according to the processing steps. Therefore, some processing areas need to use ball valves, and some areas need to use butterfly valves or gate valves.

Ball Valves

Ball valve is a commonly used valve. Suitable for flow-through, cut-off and regulation. The advantages of ball valves are their high pressure-bearing capacity, high-temperature tolerance and various installation methods. But the size range of the ball valve is limited. The cost of a large-sized ball valve may exceed your budget.

According to the flow direction requirements, the ball valve can be divided into two-way type or three-way type to meet your needs of confluence, diversion or changing the flow direction of the medium. According to the structure type, the ball valve can be divided into floating ball valve and fixed ball valve to meet your different pipeline needs.

Butterfly Valves

The butterfly valve is a quarter turn valve. The butterfly plate rotates 90 degrees with the valve stem to open or close the valve. It is suitable for on-off and control the flow rate. The advantages of butterfly valve lie in its compact design, large size range and various installation methods, which can match the installation of various pipelines. But the pressure bearing capacity of the butterfly valve is low.

Gate Valves

The gate valve is a linear operated valve. The valve plate moves straight up or down with the valve stem to open or close the valve. The gate valve can only be fully opened or fully closed, so it is suitable for circulating or blocking medium flow.

Actuator Types

The above valves can be driven by electric actuator, pneumatic actuator or handle/Gearbox. Meet your remote control and on-site control needs.


Check Valves(Non-return Valves)

The check valve is a valve that prevents the backflow of the medium, thereby ensuring the normal operation of the pipeline.


The Y-strainer is a valve used to filter impurities in the media. Thereby extending the working life of valves and pipes.

The above are valves commonly used in wastewater treatment projects and mechanical vapor recompression. If you have a demand for valves, you are welcome to consult us to obtain the optimal valve solution and cost budget. sales@covnaactuator.com

COVNA Actuator Valves For Industrial Tunnel Washers

Industrial tunnel washers provide large-scale and environmentally friendly commercial washing services. Able to use less water, and wash more cleanly. Valves play a role in conveying water or detergent in industrial tunnel washers. Helping industrial tunnel cleaners run smoothly and improve efficiency. Below, we will introduce you to the valves that can be used in industrial tunnel cleaning machines.

Ball Valves

The ball valve is a quarter-turn valve. It can assist the pipeline to realize the functions of circulation, cut-off, changing the flow direction of the medium, confluence and diversion. So the ball valve will be one of your first choice valves.

● According to the function, the ball valve can be customized into high-temperature types (suitable for controlling steam, hot water, etc.), high-pressure types (suitable for high-pressure cleaners), anti-corrosion types (suitable for controlling strong acids and alkalis, etc.), general-purpose types (suitable for for regulating ordinary water flow, etc.).

● According to the difference of the actuation mode, the ball valve can be divided into electric ball valves, pneumatic ball valves and manual ball valves. 3 actuation methods to meet the actuation needs of your project.


Butterfly Valves

The butterfly valve is a valve with a compact design, easy to operate, and a large size. It can save you installation space and purchase cost. Provide you with the services of circulation, truncation and regulation of traffic.

● Butterfly valve can be divided into soft seal butterfly valve and hard seal according to the difference of seals. Meet different temperature and pressure needs.

● According to the difference of the connection method, the butterfly valve can be divided into wafer type, flange type, lug type and clamp type to meet various installation needs of your pipeline.

● According to the driving method, butterfly valve can be divided into electric butterfly valves, pneumatic butterfly valves and manual butterfly valves. All in all, electric actuators are your first choice for smart devices. Pneumatic actuators are fast and cost-effective. Manual valves are low cost.


Gate Valves

The gate valve is a linear operated valve. It is suitable for flow-through and shut-off. Its advantages are easy installation and easy handling.

Check Valves

The check valve is an industrial valve used to prevent the backflow of the medium and ensure the normal operation of the project.

The above is an introduction to the valves that can be used in industrial tunnel cleaning machines. If you are an industrial tunnel cleaning machine manufacturer or other industrial equipment manufacturers, welcome any inquiry to sales@covnaactuator.com.


Why Choose Pneumatic Sanitary Valves?

Pneumatic sanitary valves are electronically polished as standard, and the smooth surface ensures cleanliness with no areas of media accumulation and potential contamination.

Other valves are generally modeled according to the needs of use, mainly in the high temperature and high pressure working environment, long service life and flexible operation mode.


Sanitary valves can be made of 304SS, 304L or 316, 316L stainless steel. After production and processing, they have undergone special treatment, while other valves can be made of cast iron, cast steel, ductile iron, stainless steel, and a wider range of materials.
Because sanitary valves are used in pharmaceuticals, food, daily chemicals, etc., which have high sanitary requirements, these products are all edible or in direct contact with the human body, Sanitary grades are also used in environments with strict health regulations that require a zero-tolerance policy for physical and chemical hazards.

All sanitary valves must be sterilized in order to meet certain health standards. Non-hygienic valve manufacturers cannot produce such valves because all toxic components (such as lead) must be removed, which can lead to poisoning, cancer and even death. Therefore, most sanitary valves are made entirely of stainless steel.

However, ordinary valve materials such as steel, iron, copper and other materials cannot be satisfied. First of all, steel and iron are used as valves. If the humidity in the liquid or air is relatively high, they will corrode and rust, thereby polluting the product. The same is true for copper valves, and the patina is also a toxic substance, so it cannot be used as a sanitary valve.



Sanitary valves generally adopt the way of clamp quick installation connection. While the connection methods of industrial valves include flanged, thread, welding, etc.

COVNA pneumatic sanitary valve has the following advantages:

  • Seamless
  • Easy to clean
  • Smooth and polished surface
  • These properties allow the product to flow cleanly and remain sterile without the risk of bacterial growth or other forms of contamination.


If you have a demand for pneumatic sanitary valves, feel free to consult us at sales@covnaactuator.com for suitable valve solutions.

COVNA Actuator Valves for Marine

The marine valve is a device used to control the pressure, flow and flow direction of the fluid in the ship’s pipeline to meet the environmental conditions of the ship.

The marine valve is a control device for the fluid pipeline. Its basic function is to connect or cut off the flow of the medium in the pipeline, change the flow of the medium, change the flow direction of the medium, adjust the pressure and flow of the medium, and protect the normal operation of the equipment in the pipeline.

Below I will introduce to you the actuator valves of COVNA suitable for marine use.

Knife Gate Valves

 Knife gate valve has the advantages of simple and compact structure, reasonable design, reliable sealing, light and flexible operation, running smooth, small flow resistance and easy installation. It works normally when the temperature is -10 to 425℃. The gate of the knife gate valve has a shearing function, which can scrape off the adhesive on the sealing surface and automatically remove the sundries. The stainless steel gate can prevent seal leakage caused by corrosion.

Available in pneumatic knife gate valve, electric knife gate valve and manual knife gate valve for your different actuation needs.


Butterfly Valves

Butterfly valve has the advantages of lightweight, reliable performance, simple matching and large flow capacity, especially suitable for occasions where the medium is viscous and contains particles and fibers. When the butterfly valve is in the fully open position, the thickness of the butterfly plate is the only resistance when the medium flows through the valve body, so the pressure drop generated by the valve is very small. So it has better flow control characteristics. The butterfly valve has two sealing types such as soft seal types and metal seal types.

At present, the valve is widely used in food, environmental protection, petroleum, papermaking, chemical industry, teaching and scientific research equipment, electric power and other industries.

The butterfly valve could be driven by electric actuator, pneumatic actuator and manual override.


Ball Valves

Ball valve is a common use valve. Widely used for transport, shut-off, change the direction of flow rate and control the flow rate. It could be customized into high-temperature types, high-pressure types, anti-corrosive types and universal types. Suitable for water, steam, oil, fuel, air, and so on. Offering a reliable valve solution for you.

Also available in electric operated type, pneumatic operated type, and manual operated type.

Here is a brief introduction of valves for marine. Any demand for valves, feel free to consult us at sales@covnaactuator.com for a cost-effective valve solution.


What Is The Difference Between Pneumatic Ball Valves And Pneumatic Butterfly Valves?

According to the valve type, the pneumatic actuator valve could be divided into pneumatic ball valves and pneumatic butterfly valves.

Pneumatic ball valve is a valve that uses a ball with a circular channel as the opening and closing part, and the ball rotates with the valve stem to realize the opening and closing action. The opening and closing part of the ball valve is a sphere with holes, which rotates around the axis perpendicular to the channel, so as to achieve the purpose of opening and closing the channel.

Pneumatic butterfly valve is a quarter valve used to open, close and regulate fluid flow. It has a simple operation. A 90-degree rotation of a valve or actuator completely opens or closes fluid flow.

Working Principle

Pneumatic ball valve has a 90-degree rotation action, just because its opening and closing part is a sphere, it can be opened or closed only by operating a 90-degree rotation, which is the most suitable for switching. But now the V-shaped ball valve can be used to regulate or control the flow.

Pneumatic butterfly valve is a kind of valve that uses a disc-type opening and closing member to reciprocate about 90° to open, close or adjust the flow of the medium. It has a good function of adjusting the flow and is one of the fastest-growing valve varieties.



Pneumatic ball valves always rotate, no matter how much pressure is applied. Once opened, the pressure hardly drops because the hole in the ball allows 100% flow of gas or liquid.

Pneumatic butterfly valves are constructed so that a portion of the valve flap always interferes with the flow of liquid or gas. This means that there is always a pressure drop when using a butterfly valve. This also means that the butterfly valve may be difficult to open



Pneumatic ball valves are more effective at sealing than pneumatic butterfly valves, so ball valves are generally better suited for projects involving gas flow.

Pneumatic butterfly valves are typically less expensive to build and maintain, so they are commonly used in large municipal water and sewer projects. They are also common in projects that control the flow of water in rivers or streams.

Any demand for pneumatic ball valves or pneumatic butterfly valves, feel free to consult us at sales@covnaactuator.com for a suitable valve solution.



What is COVNA Pneumatic Control Valve?

Pneumatic control valves are mainly used in transportation systems in medical, food, petroleum, natural gas, water treatment, and other industries, and are suitable for controlling gas, steam, liquid, and other media. Compared with other general pneumatic actuator valves, it adds some control components, and the whole is more complicated, so the required debugging process is naturally more complicated.

Today, we will talk to you about the COVNA pneumatic control valve.

It is characterized by simple control, fast response, intrinsic safety, no need to take additional explosion-proof measures and receives control signals from industrial automation control systems to adjust various process parameters such as flow and pressure of pipeline media.

Pneumatic control valve is usually composed of a pneumatic actuator and modulating valve connection, installation and debugging. Pneumatic actuators can be divided into two types: single-acting and double-acting. There is a return spring in the single-acting actuator, while there is no return spring in the double-acting actuator. Among them, the single-acting actuator can automatically return to the open or closed state initially set by the valve in the event of loss of origin or sudden failure.

The pneumatic control valve is divided into two types: air-opening and air-closing according to the active form, the so-called normally open type and normally closed type. The air-opening or air-closing of the pneumatic control valve is usually through the positive and negative action of the actuator and the valve state structure of different assembly methods.


What Is The Function Of The Pneumatic Control Valve?

It can be used to adjust the flow rate and pressure of the valve medium, convert the air pressure into motion and use the air as the control medium to open, close or adjust the flow rate as required by the pneumatic actuator.

Applications Of Pneumatic Control Valves

  • Shipbuilding
  • Power Plants
  • Food & Beverage
  • Wastewater Treatment
  • Boiler
  • Paper & Pulp
  • Chemical

If you have any demand for pneumatic control valves, feel free to consult us at sales@covnaactuator.com for a suitable valve solution.


What Is COVNA Pneumatic Knife Gate Valve?

Pneumatic knife gate valve is a relatively complex automatic control, which is composed of a variety of pneumatic components and valve bodies. It is suitable for medium pipelines such as syrup, paper pulp, sewage, coal slurry, ash, dust, and slag-water mixture.

In the past, such as in paper industry applications, viscous pulp can get stuck in the valve seat of ordinary gate valve and prevent the valve from closing, causing the valve seal to leak, but the knife gate valve is specially designed so that the valve has a sharp edge, which can be cut open viscous media and seal to prevent leakage.

Pneumatic actuators are the most affordable and economical way to drive a knife gate valve. Because knife gate valves are only suitable for on-off use, not media modulating applications, the design features are ideal for installing pneumatic actuators.

Pneumatic knife gate valves are mostly used in occasions requiring quick shut-off or opening, the gate has a shearing function, which can scrape off the adhesive on the sealing surface and automatically remove the sundries. Due to this special design, pneumatic knife gate valves are very effective in applications involving viscous fluids, slurries and other media.

In this article, I will introduce to you the advantages and characteristics of COVNA Pneumatic Knife Gate Valves

In COVNA, pneumatic knife gate valves are available in Cast iron, carbon steel and stainless steel. The pneumatic actuator has linear series and an imported actuator series to choose from.

The advantages of our pneumatic knife gate valve are ultra-thin design, full diameter flow, not easy to leak, easy disassembly and assembly, movable sealing structure, strong cutting force, good sealing performance, strong wear resistance, automatic compensation, long life, not easy to accumulate and low torque.


Applications Of Pneumatic Knife Gate Valves

  • Cement plants
  • Solid waste treatment
  • Paper and pulp
  • Wastewater treatment

If you have any demand for pneumatic knife gate valves, feel free to consult us at sales@covnaactuator.com for a suitable valve solution.

Pneumatic Actuator Valve For Reverse Osmosis System

Reverse osmosis (RO) system uses the principle of reverse osmosis to remove mainly dissolved salts from water while removing some macromolecules and small particles etc. that were not removed in the previous stage. The pneumatic actuator valves can play a lot of roles in this system.

It is mainly driven by pressure, forcing the solvent in the solution to separate from the solute by the retention effect of the semi-permeable membrane.

In the following, we will introduce you the valves that can be used in reverse osmosis systems. We hope this will help you understand and select the right valve.

Pneumatic Butterfly Valve

The main advantages of pneumatic butterfly valve are simple structure, small volume and weight, can also regulate the flow of media. Fluid resistance is small, medium and large diameter pneumatic butterfly valve full open effective flow area is larger, opening and closing quickly and effortless, disc wrench rotation 90 angles to complete opening and closing.

Pneumatic Ball Valve

Pneumatic ball valves are mainly used in pipelines to cut off fast, distribute and change the flow direction of the medium.

The switch is light, small in size, can be made into a large diameter, can be sealed, has a simple structure, and is easy to maintain.


Check Valve

The main function of the check valve is to prevent the backflow of the medium, to prevent the reverse rotation of the pump and the driving motor, and discharge the medium into the container. It is very suitable for use in the RO system to prevent the backflow of the water medium.

Globe Valve

It is a very important cut-off class valve, whose seal is made by applying torque to the valve stem, which exerts pressure on the valve flap in the axial direction so that the sealing surface of the valve flap fits closely with the sealing surface of the valve seat and stops the medium from leaking along the gap between the sealing surfaces.


COVNA Automated Valves For Brackish Water Desalination

What is Brackish water desalination?

Brackish water desalination is actually the desalination of salt water, so that the salt water is desalinated or treated to meet the drinking water standard.

There are many methods of desalination of brackish water and seawater, mainly distillation, electrodialysis and reverse osmosis. At present, reverse osmosis and electrodialysis are mostly used in the desalination of brackish water. The reverse osmosis method has a tendency to catch up with the latecomers due to its low investment and low energy consumption.

Using reverse osmosis technology, because chloride is not used for other substances, it can be removed by a certain filter material, and the removal process of chloride is generally treated by reverse osmosis technology, and this step will use automatic valve treatment

Below, we will introduce COVNA automated valves that can be used for brackish water desalination.

Pneumatic Control Valve

Control valve can precisely regulate the flow, pressure and temperature of the medium, making your automation easier, helping you control the medium more accurately, without electricity, and safe and explosion-proof. Enable industrial automation to help you control flow rate remotely.


Electric Ball Valve

Electric ball valves are available in stainless steel, UPVC or carbon steel materials, and are used for the regulation and control of various fluids. Among them, electric V-shaped ball valves are especially suitable for shut-off media containing fibers and tiny solid particles. Strong vibration resistance and easy installation. Performance indicators are better than similar products.


Pneumatic Butterfly Valve

The pneumatic butterfly valve can be opened and closed quickly with only 90 rotations, and the operation is simple. At the same time, the valve has good fluid control characteristics. Commonly used are pneumatic flange butterfly valve and pneumatic wafer butterfly valve.


Check Valve

Relying on the flow of the medium itself, the valve flap is automatically opened and closed to prevent the backflow of the medium, also known as check valve and one-way valve.