Powder system? There are other factors that need to be considered for the powder system of the pneumatic butterfly valve, such as: materials cannot be directly rushed to the valve plate when they are put into the trolley from above (this impact force will also make the valve cannot be closed tightly), and the static pressure of materials must not exceed the design bearing pressure of the pneumatic butterfly valve, etc.? The difference between the control valve and the ordinary manual valve is that it cannot be regarded as an isolated element, but must be considered as a part of the entire automatic control system. Many problems in the use of the control valve are not the problem of model selection and configuration, but because the user's lack of understanding of the control valve causes the control valve to fail to debug and cooperate well with the control system. As long as we recognize the key point of the problem, correctly select the valve, and properly debug the control valve in the system commissioning stage, we can greatly reduce the failure rate and make the automatic control system operate stably for a long time.

Movement mode and reference specification of rectangular non-metallic compensator
In the pipeline system, if the thermal stress caused by temperature change, the partial stress caused by equipment vibration and fixed support, and the stress caused by system device deflection exist at the same time, the rigid connection mode will inevitably lead to deformation or destruction of the pipeline system at the thinnest place. If flexible rectangular non-metallic compensator is used, this kind of damage can be prevented. This is related to the unique motion mode of non-metallic compensator. These motion modes determine the multi-dimensional displacement performance of non-metallic compensators.
In view of the complex displacement situation, the metal compensator usually needs to use the complex structure and high price of the compound pull rod type, which can make the system get multi-directional compensation. Of course, in some complex displacement places with high working temperature and pressure, it is also necessary to use a compound metal compensator.
The following specifications shall be referred to when selecting metal contraction joints:
1. State -- The length of the compensator hose shall be correctly selected and correctly installed according to the state of the hose in use, with reference to the correct application and installation method of the pneumatic butterfly valve and the optimal length of the hose in settlement compensation, the length calculation of the hose in various motion states, and the minimum bending times and minimum bending radius of the hose.
2. Size -- nominal diameter of hose, selection of connector type contraction joint (mainly flange connection, thread connection, quick connector connection) and size, hose length.
3. Pressure - according to the practical working pressure of the hose, check the nominal diameter of the corrugated pipe and the pressure gauge, and decide whether to use the stainless steel mesh sleeve type.
4. Medium -- the chemical properties of the medium recommended in the hose, and the material of each part of the hose shall be determined according to the corrosion resistance parameter table of hose material.
5. Temperature -- working temperature and range of medium in hose; Ambient temperature when the hose is working. In case of high temperature, it is necessary to confirm the pressure after temperature correction according to the temperature correction coefficient of working pressure under high temperature of metal contraction joint, so as to ensure the correct pressure level is selected.
The metal contraction joint is a kind of flexible structure set on the vessel shell or pipeline to compensate the additional stress caused by temperature difference and mechanical vibration. As an elastic compensation element that can stretch freely, it has the advantages of reliable operation, good performance and compact structure. Metal contraction joints can be divided into elbow type contraction joints, bellows contraction joints and sleeve expansion joints.