Products knowledge
butterfly valve---2009-10-21
Pneumatic butterfly valve on the gas, liquid medium occasions we have already discussed the use of relatively more, and since the pneumatic valve for solid materials (such as dust, powder) and there is not much, so in the selection and use also there are many places worth exploring. Here to talk about the practical application of experience gains and opinion.
control valve for solid materials, often in the tank bottom as a discharge valve to use, such as cement cans, powder cans, etc. tank bottom, is used to discharge and rapid cutting. Because most of the dust material containing large or small particles, the wear and tear on the valve sealing surface is no doubt, the selection of properly, will greatly reduce the life of the valve, or will soon result in valve leakage, affecting its continued use. There is such a case: There is an ingredient weighing system, the entire batching process to achieve fully automatic with PLC control, batching trolley discharge valve choices are the pneumatic three eccentric butterfly valve, the medium is a very fine powder particles. With a period of time, the customer reflecting the leakage within the valve, resulting in powder piles of earth leakage current in the table. Valve Depot, there are no leak detection, and customers are used to reflect before this valve, and the same media, there has not been such a thing. In order to understand the whole story, the company sent to the scene, and finally find out the reasons: the original, this medium is very small, and a bit sticky, though a small car equipped with a vibrating motor ingredients, and finally there are a lot of material attached to the tank wall and valve parts , in the valve closed, stuck in the sealing surface around the valve can not be completely closed, resulting in re-installation of materials leak occurred after the passage of time, but also so that the sealing surface wear is very fierce, and even emerged in groove to.
identify the reason for the proposed solution: In the PLC program will be extended vibration motor as far as possible all the shock out of the material after the closure of the valve; to 0:00 weighing instrument alignment is bound to be all out of material after shows zero, this time before the valve is closed by the PLC to issue a signal; three eccentric butterfly valve will be replaced by pairs of flexible eccentric hard sealing butterfly valve (rubber sealing butterfly valve centerline can also be used, taking into account materials, an occasional large particles, rubber seal may not be durable - if there is no particle powder material, could be considered soft seal butterfly valve), because the three eccentric butterfly valve seat sealing surface is an oblique, that is, face seal, so material is easy to accumulate in sealed surface can not be quickly discharged, while the single-or double-eccentric butterfly valve eccentricity no such abuses, even a little sealing surface materials, but also when the valve closed valve plate scraped, and to ensure a good seal, and the sealing surface durability. After this some transformation, such problems never occurred.
In such a system, there are other needs, taking into account factors such as: can not let the material from above into the small car rushed directly to the valve the valve plate (which will also impact the valve can not close tightly) , and the materials also need to hydrostatic pressure does not exceed the design bearing pressure of pneumatic butterfly valve, and so on.
control valve manual valves with common difference is that you can not put it as an isolated component to look at, but must put it as part of the system as a whole to consider the self-control, control valves used in many of the issues, is not the selection and configuration, but because users lack of understanding of the control valve control valve failure caused and control system commissioning, with the good. As long as the key to understanding the problem, the correct selection of valves, and system debugging stage, the control valve to debug is good, will be able to significantly reduce the failure rate, so that long-term stable operation of automatic control system.
control valve for solid materials, often in the tank bottom as a discharge valve to use, such as cement cans, powder cans, etc. tank bottom, is used to discharge and rapid cutting. Because most of the dust material containing large or small particles, the wear and tear on the valve sealing surface is no doubt, the selection of properly, will greatly reduce the life of the valve, or will soon result in valve leakage, affecting its continued use. There is such a case: There is an ingredient weighing system, the entire batching process to achieve fully automatic with PLC control, batching trolley discharge valve choices are the pneumatic three eccentric butterfly valve, the medium is a very fine powder particles. With a period of time, the customer reflecting the leakage within the valve, resulting in powder piles of earth leakage current in the table. Valve Depot, there are no leak detection, and customers are used to reflect before this valve, and the same media, there has not been such a thing. In order to understand the whole story, the company sent to the scene, and finally find out the reasons: the original, this medium is very small, and a bit sticky, though a small car equipped with a vibrating motor ingredients, and finally there are a lot of material attached to the tank wall and valve parts , in the valve closed, stuck in the sealing surface around the valve can not be completely closed, resulting in re-installation of materials leak occurred after the passage of time, but also so that the sealing surface wear is very fierce, and even emerged in groove to.
identify the reason for the proposed solution: In the PLC program will be extended vibration motor as far as possible all the shock out of the material after the closure of the valve; to 0:00 weighing instrument alignment is bound to be all out of material after shows zero, this time before the valve is closed by the PLC to issue a signal; three eccentric butterfly valve will be replaced by pairs of flexible eccentric hard sealing butterfly valve (rubber sealing butterfly valve centerline can also be used, taking into account materials, an occasional large particles, rubber seal may not be durable - if there is no particle powder material, could be considered soft seal butterfly valve), because the three eccentric butterfly valve seat sealing surface is an oblique, that is, face seal, so material is easy to accumulate in sealed surface can not be quickly discharged, while the single-or double-eccentric butterfly valve eccentricity no such abuses, even a little sealing surface materials, but also when the valve closed valve plate scraped, and to ensure a good seal, and the sealing surface durability. After this some transformation, such problems never occurred.
In such a system, there are other needs, taking into account factors such as: can not let the material from above into the small car rushed directly to the valve the valve plate (which will also impact the valve can not close tightly) , and the materials also need to hydrostatic pressure does not exceed the design bearing pressure of pneumatic butterfly valve, and so on.
control valve manual valves with common difference is that you can not put it as an isolated component to look at, but must put it as part of the system as a whole to consider the self-control, control valves used in many of the issues, is not the selection and configuration, but because users lack of understanding of the control valve control valve failure caused and control system commissioning, with the good. As long as the key to understanding the problem, the correct selection of valves, and system debugging stage, the control valve to debug is good, will be able to significantly reduce the failure rate, so that long-term stable operation of automatic control system.
