Difference between pressure relief valves and self-acting pressure regulators
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This post was last edited by kkbbaa on 2019-11-27 at 16:42. Hello, experts. Both pressure relief valves and self-acting pressure regulators achieve pressure reduction by utilizing the pressure of the medium itself. What are the differences between these two types of valves? Currently, there are two process options here; the medium is natural gas, and the pipeline diameter is DN80. Option 1: The pressure before the valve ranges from 6 to 16 bar, and this value can vary depending on requirements. It is necessary to reduce the pressure to 6 bar, after which another process unit adjusts the pressure as needed. Another option: the pressure before the valve is 6~16 bar, and this value can vary according to requirements; the pressure after the valve can be adjusted directly to 0~6 bar depending on the situation. That is, the pressures before and after the valve both vary within a certain range. In situations like these, for the first case, should a pressure reducing valve be used or a self-acting control valve? Should the second option simply use a pneumatic pressure control valve? I would appreciate some advice from the more experienced members; thank you all!!!
This post was last edited by CHANGBAISHI on 2019-11-27 at 16:41. The principle of a pressure relief valve is to maintain a relatively stable pressure through the interaction between the spring and the force application area of the valve core. The self-acting control valve builds on this foundation by introducing a pilot pressure line that exerts force on the valve stem cylinder, enabling more precise adjustment according to the pressures on either side of the valve. For DN80 and below, a self-acting control valve is the preferred choice. For larger pipe diameters, it is better to use pneumatic control valves. Additionally, a drawback of pressure relief valves is the issue of leakage, which should be given attention. Typical pressure relief devices of this kind have valve assemblies with a fixed installation method. In other words, a stop valve should be installed before the control valve, and connection valves should be placed before and after the valves at both ends for use during maintenance and adjustment. After pressure reduction, a safety valve and a pressure gauge must also be installed. For reference.
Hello, senior. Thank you for your reply. The pipe diameter is DN80. Does that mean that in any case, it’s better to use a pneumatic control valve, as this would allow for greater precision?
Check online (or on Taobao); there are tables detailing the specifications of self-acting pressure relief valves, so you can find the information easily, or consult the manufacturers and suppliers. Using a self-acting pressure relief valve should work; this is for reference only.
Regarding maintenance, ideally there should be two pressure regulators, one in use and one as a backup. In practice, however, even with a bypass in place, if a pressure regulator fails, the system cannot reduce the pressure to the required level unless another pressure regulator is installed. There is also a pressure gauge; I feed the gas that has been depressurized into the buffer tank before supplying it. In this case, can the pressure gauge on the buffer tank replace the one located after the pressure reducing valve? Thank you for your guidance, senior! ! !
It is recommended to add a bypass line to the imported pressure reducing valve. To allow for the replacement of the filter element and maintenance. Self-acting control valves have a higher failure rate.
The safest approach is to divide the pipeline into two branches; install filter-pressure regulators and inlet/outlet valves on each of these two pipelines, and then combine the two branches back together. The two filter pressure relief valves are in a use-one-and-backup-one configuration. It is ensured that if one pressure relief valve fails, after closing the manual valve on that line, the other one can be put into use immediately, still maintaining a reduced pressure state.
It is recommended to check on Taobao and browse the drop-down content, where there are flowcharts including the valve assemblies. This is a standard valve assembly; all your questions are addressed within it. First of all, I want to clarify that I’m not doing advertising; I’m just sharing a website for reference: https://item.taobao.com/item.htm?spm=a230r.1.14.20.64652a1bjOZjAb&id=586153350995&ns=1&abbucket=1#detail
For caliber 80, the first type uses a pressure reducing valve with a branch line, while the second type uses a control valve – it has a pleasant aroma