Pneumatic two-stage ball valve

Brief description: Pneumatic two-stage ball valve is composed of five main parts: fireproof ball valve, pneumatic actuator, solenoid valve, filter pressure reducing valve, and limit switch. It is controlled by an electromagnetic pilot valve and driven back and forth by a dual piston gear rack pneumatic actuator to open and close the ball valve. Through computer programming, automatic control can be achieved for one or multiple stages of opening and closing, with high control accuracy, which belongs to a new type of product. The FBVAA two-stage pneumatic ball valve is connected separately between the pneumatic control part and the medium contact part.

Pneumatic two-stage ball valveIntroduction, Main Technical Parameters, and Installation and Debugging Instructions
1Pneumatic two-stage ball valveProduct Introduction and Features
The FBVAA series two-stage pneumatic ball valve is composed of five main parts: fireproof ball valve, pneumatic actuator, solenoid valve, filter pressure reducing valve, and limit switch. It is controlled by an electromagnetic pilot valve and driven back and forth by a dual piston gear rack pneumatic actuator to open and close the ball valve. Through computer programming, automatic control can be achieved for one or multiple stages of opening and closing, with high control accuracy, which belongs to a new type of product.
The valve is connected separately from the medium contact part due to the pneumatic control part. It can be used for ordinary media such as light oil, gas, water, as well as various high viscosity or corrosive media such as crude oil, chemicals, and mixed media.
This series of valves is easy to operate, flexible in control, and easy to maintain. The actuator is widely used in industries such as petroleum, chemical, power plants, steel, and water treatment, and is matched with ball valves, butterfly valves, fan baffles, etc. For example, automated oil storage and receiving control systems, chemical storage and other automated receiving and sending systems, fire automation control systems, etc.
Control various gas and liquid media through the loading instrument; Mixed liquid media can achieve precise control and automatic control of the flow rate, flow velocity, and pressure of the conveying medium. It has the ability to prevent "water hammer" and can be controlled automatically and manually, with controllable functions for large and small flow rates.
This valve can be controlled automatically or manually. According to user requirements, 110V, 220V AC voltage or 12V, 24V, 36V DC voltage can be used.
The VAA series pneumatic ball valve has passed the national explosion-proof inspection. Each cylinder undergoes pressure testing and standard manufacturing labeling before leaving the factory, and is guaranteed to operate more than 500000 times.
IIWork technical conditions and main technical parameters
1) Media used: Compressed air, non corrosive gases, and oil:
2) Pressure range: Double acting 2-8 bar, single acting 2-8 bar
3) Working temperature: Standard type: -20 ℃~+80 ℃
Low temperature type: -40 ℃ to+80 ℃; High temperature type: -20 ℃ to+160 ℃.
4) Maximum usage pressure: Input air pressure does not exceed 10 bar (Bar);
5) Travel adjustment: There is an adjustable range of ± 4 degrees at the 90 degree position
6) Torque: 6~3000Nm;
7) Control mode: switch type, regulating type, bus control (requires solenoid valve, locator);
8) Action frequency: 2000 times/hour;
9) Input signal: ON/OFF, 4~20mA, 0~10V (requires solenoid valve and locator);
10) Output signal: 4~20mA, contact signal (requires locator and limit switch);
11) Environmental temperature: -35 ℃~+85 ℃;
12) Protection level: Waterproof IP65, Explosion proof EEx-dIIBT4/EExdIICT4.
IIIInstallation and Debugging Instructions
（1） Usage restrictions
1. Temperature and pressure limitations
(1) The nameplate displays the maximum allowable operating pressure of the ball valve at maximum and minimum operating temperatures;
(2) The valve seat and seal made of cast steel or all stainless steel material should be operated at a temperature between -29 ℃ and 180 ℃.
The operating temperature of other types of valve seats and seals can be customized;
(3) The nominal pressure rating (PN) of a valve: It indicates the maximum operating pressure of the valve at normal temperature. (For example: PN40,
Indicating that the maximum working pressure is 40Bar when the operating humidity is between -29 ℃ and 38 ℃;
2. Prohibit throttling operation
Please do not keep the ball valve in a half open state frequently (flow control), as pressure differences in the pipeline and fluid impact may cause damage to the ball valve or valve seat.
(II)Installation and Maintenance
1. Installation
(1) Remove the protective covers on both sides of the flange end and rinse and clean with the valve open;
(2) Before preparing to connect with the pipeline, rinse and remove all accumulated impurities in the pipeline (which may damage the valve seat and ball);
(3) Before installing the valve, carefully check whether the valve chamber is clean. If there are any debris, make sure to clean it thoroughly. Check if the flange surface is damaged and ensure that it is undamaged. During the installation process, the connecting pipe should not be subjected to force, otherwise it may cause air leakage.
(4) Wiring: Open the explosion-proof junction box, there are a total of 5 terminals, ①, ②, ③, ④ and grounding, where ① and ② are a group, connected to solenoid valve 1; ③ and ④ are a group, connected to solenoid valve 2.
(5) During installation, please do not use the valve stem or handle (handwheel) part of the valve as a fulcrum for lifting objects to avoid collapse and other accidents;
(6) The pipeline near the installation point should not have low hanging or external force bearing objects, and pipeline brackets or supports can be used to clear the deviation of the pipeline;
(7) After connecting with the pipeline, please use the specified cross locking flange connection bolts;
(8) During the handling and installation process, be sure to handle with care to avoid damage, deformation, and loosening of the gas pipeline and various joints.
2. Maintenance of FBVAA two-stage pneumatic ball valve
This product has a long service life and maintenance free period. The actual service life depends on the following factors: normal working conditions, maintaining a harmonious temperature/pressure ratio, and reasonable corrosion data.
Maintenance precautions:
(1) When the ball valve is in the closed state, there is still pressurized liquid inside the valve body;
(2) Before maintenance, release the pipeline pressure and keep the valve in the open position;
(3) If there is slight leakage at the packing point, the valve stem nut must be tightened again, but be careful not to tighten it too tightly. Usually, tighten it half a circle more, and the leakage will stop.
(4) Wiring: Open the explosion-proof junction box, there are a total of 5 terminals, ①, ②, ③, ④ and grounding, where ① and ② are a group, connected to solenoid valve 1; ③ and ④ are a group, connected to solenoid valve 2.
（3） Operation and use of FBVAA two-stage pneumatic ball valve

(1) Before operation, it is necessary to confirm that the pipelines and valves have been thoroughly flushed.
(2) The operation of the valve is completed by rotating the valve stem (manual or automatic control mode): when rotated clockwise by 1/4 turn (90 degrees), the valve closes. When rotated counterclockwise by 1/4 (90 degrees), the valve opens.
(3) When the direction of the groove on the top of the handle or valve stem is parallel to the pipeline, the valve is in the open state.
(4) Gas source requirements: The gas source should be clean and free of oil stains, with a pressure of 4-8 bar.
(5) Wiring: Explosion proof conduit should be connected to the inlet end of the explosion-proof junction box for wiring.
（4） Control principle and steps of FBVAA two-stage pneumatic ball valve
1. Control principle
The control principle is shown in Figure 3. Taking loading as an example, the specific process is that solenoid valve 1 is energized, all valves are opened, and loading is carried out. When approaching the set value, solenoid valve 2 is energized, and solenoid valve 1 loses power (note that solenoid valve 2 loses power 3 seconds after being energized). The valve enters a low flow state. When the flow reaches the set value, solenoid valve 2 loses power and all valves are closed.
Under normal circumstances, the solenoid valve of the emergency shut-off valve should be powered off and in a normally open state, while the valve body should be in a closed state when there is no air source. When using air source operation, the first thing to confirm is that the adjustment screw and locking nut of the manual mechanism are in a disengaged state. When operating, first turn on the air source. When the pressure of the instrument air source is greater than 0.3Mpa, the piston rod moves forward under force, squeezes the spring, and drives the shaft and valve stem to rotate, causing the valve core to open and the valve to be opened.
If the cut-off valve needs to be closed, the upper computer issues a closing command to turn on the solenoid valve and close it, releasing the gas in the cylinder. When the pressure of the instrument gas source drops below 0.1Mpa, the spring force is greater than the gas source pressure, causing the piston rod to move backward and the shaft to start reverse movement. When the pressure drops to zero, the shut-off valve is closed.
When using manual mechanism operation, the first step is to cut off the air source, exhaust the air in the cylinder, and make the instrument air source pressure zero.
At this time, the shut-off valve should be in the closed state due to the lack of air pressure. If you want to open the shut-off valve, you should rotate the handle on one side of the spring cylinder counterclockwise. When the adjusting screw is about 8cm out of the spring cylinder, you can clearly feel the resistance. At this point, the screw of the manual mechanism is locked by the locking nut. Continue to rotate the handwheel counterclockwise until the adjusting screw drives the spring to stretch, causing the piston rod to move forward. When the adjusting screw is about 21cm out of the spring cylinder, the shaft completes a 90 'rotation. At this point, the shut-off valve is opened.
If you want to close the shut-off valve, you should turn the handwheel clockwise. At this time, the spring slowly returns, causing the piston rod to move backward and the shaft to rotate in the opposite direction. When the length of the spring cylinder for adjusting the screw release is 8cm, the spring returns to its original position. The shut-off valve is closed. Continue to rotate the handwheel clockwise, and when no resistance is felt, the screw of the manual mechanism disengages from the locking nut. During manual control, it is strictly prohibited to open the air source for ventilation.
When the cut-off valve is in the normally open state, the adjusting screw of the manual mechanism cannot be locked by the locking nut.
2. Control steps:
Taking the example of one stage opening, two stages closing, and small flow control, the specific control steps are as follows:
(1) ①, ② are electrified, all valves are opened, and loading is carried out;
(2) When approaching low flow control, ⑧, ④ are charged;
(3) After 3 seconds, ① and ② lose power, and the valve closes to a low flow state;
(4) When the loading is completed, ⑧ and ④ lose power and the valves are fully closed.
(5) If reloading, repeat steps (1) to (3).
3. Small flow opening adjustment:
The VAA pneumatic two-stage ball valve can pause once during the opening or closing process, allowing for precise flow control according to system requirements. It is particularly suitable for chemical or oil loading systems, such as opening all valves at once to start loading. When the flow rate approaches the set value, the valve closes to a low flow state, and when the set value is reached, all valves are closed. Small traffic can be set on-site between 0 and 45%, such as 5%, 8%, 10%, 15%, etc., to achieve precise control. The small flow rate has already been set at the factory. If on-site adjustment is required, the steps are as follows:
(1) Loosen the protective sleeves at both ends;
(2) Use an Allen wrench to loosen the locating pin on the copper shaft;
(3) Rotate a section of the copper shaft by hand to set a smaller flow rate, rotate the copper shaft clockwise to set a larger flow rate, rotate the copper shaft counterclockwise, adjust and fix the positioning pin tightly, conduct a ventilation test, and see if it meets the requirements. If not, adjust it several times until it meets the requirements.
(4) In the fourth control step, in the second step, rotate the other section of the copper shaft by hand to ensure that both ends are in the fourth control step. In the third step, tighten the cylinder end cover tightly and apply force while tightening the positioning pin.
(5) Cover both ends with protective end caps.

If you have any questions, please call the Technical Service Center of Naidong Valve (Shanghai) Co., Ltd.:
+86-21-