Regarding the functions of pneumatic control valves, amplifiers, and quick-release valves
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Dear seniors, I have some questions regarding the use of pneumatic control valves, amplifiers (Boosters), and quick-release valves. I’ve been dealing with valve manufacturers quite a lot lately, and I’m feeling a bit confused by all the complexities involved; I would appreciate everyone’s advice. Pneumatic valves function similarly to solenoid valves, but require an external signal air line. Generally, it is believed that pneumatic valves can increase both the intake and exhaust volumes, as well as the actuation time of the pneumatic valves, by using a “small-to-large” configuration. The amplifier increases the intake air flow and prolongs the valve actuation time. The quick exhaust valve is used to speed up exhaust. My questions are as follows: (assuming the valve is FC): 1. Does the amplifier provide a fast discharge function? As I understand it, when the inlet of the amplifier is closed, exhaust can only occur through the exhaust port; however, the size of this exhaust port is limited. Therefore, I believe that the amplifier cannot enable rapid exhaust via a control valve – it can only increase the time it takes for the valve to open. I wonder if my understanding is correct. 2. The main function of a pneumatic control valve is to control larger systems using smaller ones. If the interface of the solenoid valve can match that of the pneumatic control valve, then it might not be necessary to use a pneumatic control valve after all, as such a valve requires an additional solenoid valve to provide the control signal for the air flow. (Since we have high requirements for solenoid valves, we are not willing to cut costs on them.) 3. We have specific requirements regarding the shutdown time. The solution proposed by the manufacturer is to install a quick-release valve at the outlet of the cylinder, with the air intake controlled by a solenoid valve that operates a pneumatic valve; all these components are to be installed near the cylinder. The manufacturer is probably thinking of using a smaller component to replace a larger one. I’m not quite sure to what extent a quick-release valve can accelerate exhaust flow. In that case, would it be possible to omit the quick-release valve and use the exhaust port controlled by the pneumatic valve instead?
\ud83d\udc4f Please feel free to speak up; let’s work together
1: Amplifiers can achieve fast discharge functionality, but the range is limited. So far, it has only been used in control valves. 2: Personally, I think that for cylinders with a small volume, air-controlled valves are not necessary ； But once it reaches a certain size, the inlet and exhaust speeds of the solenoid valve can no longer keep up. 3: The solution provided by the manufacturer involves exhausting air directly through a quick-release valve. Do your three questions pertain to a specific valve?
I understand this issue. The first amplifier is also known as a speed booster; it is generally used in combination with a positioner. Its main function is to increase the intake air velocity, and it also has a certain fast exhaust function. However, this fast exhaust refers to exhausting air from the positioner, and its exhaust capacity is limited. In the case of on-off valves, that is, valves that are merely solenoid valves, an air-controlled valve or a quick-release valve is used; both of these serve to enable rapid exhaust of air, with little effect on increasing the inflow rate. This is because, due to their structural principles and power consumption constraints, solenoid valves generally have a low flow capacity. However, there are also solenoid valves with high flow capacity. The function of an air-controlled valve is similar to that of a quick-release valve, but the quick-release valve offers a better exhaust performance – it has a larger capacity and can exhaust air much more quickly. In such cases, a quick-release valve is chosen
If your sole purpose is to ensure the intake and exhaust speeds of the valve, thereby controlling its opening and closing times, I personally recommend using a direct-acting solenoid valve in the intake line. There’s no need to use a pilot-operated solenoid valve, as its intake orifice is relatively small compared to that of a direct-acting valve. For exhaust purposes, however, it’s still necessary to install a fast exhaust valve; these valves offer very high exhaust speeds. The exhaust ports built into standard solenoid valves are relatively small, resulting in slower exhaust rates. Generally speaking, what needs to be ensured is the valve’s closing time; there are usually no strict requirements regarding its opening time. The main objective is to guarantee safety. Additionally, it depends on the volume of your cylinder: for typical rack-and-pinion cylinders, standard configurations suffice. Fast exhaust valves are only required for fork-type actuators, since those cylinders have considerably larger volumes.
Thank you for the reply. We require the valves with a size of 4”-6” to close within 5 seconds; we consulted several manufacturers of globe valves, and they all use diaphragm actuators, which seem not to meet the requirements.
Thank you for the reply. They are valves for the same operating conditions, with a size of 4” to 6”, and it is required that they close within 5 seconds. I consulted several globe valve manufacturers, and it seems that those using diaphragm actuators cannot meet this requirement. Those using piston actuators with air control valves and quick-release valves in their air supply system also fail to meet the requirements. I also asked several butterfly valve manufacturers; they all use rack-and-pinion actuators. A few of them said they could meet our requirements. However, one manufacturer still added a pneumatic control valve and a quick exhaust valve (the same company that makes globe valves). They advised against closing the valve too quickly, stating that it would affect the valve’s lifespan. It’s really confusing – why did this company make the air supply system so complicated?
If it’s a shut-off valve, why not use one with angular travel? It’s indeed difficult to implement one with linear travel. .