A practical issue regarding safety valve leakage
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We distribute safety valves of the Xfu brand, sourced through legitimate channels. The customer is a boiler manufacturer; the operating conditions are steam at temperatures not exceeding 180 degrees Celsius, with an operating pressure of around 0.78. Recently, a strange phenomenon has emerged: although the valves pass all the tests conducted during regular inspections, many of them develop seal surface leaks – that is, internal leakage – after just 1 month of use, or at most 2 to 3 months; in some cases, they even start to malfunction earlier than that. The explanation given by the factory is usually that the sealing surface is damaged; the valve has been disassembled, and there are indeed some small pits on the sealing surface. Question 1: Does the seal surface leak first and then get damaged, or does it get damaged first and then start leaking? Another detail is that the supply is generally done at a set pressure of 1.0 MPa, with the pressure range being between 0.8 and 1.0 MPa. Customers will make appropriate adjustments at the boiler inspection agency based on actual conditions; some adjust it to 0.85, while others adjust it to 0.88, which is roughly 1.1 times the operating pressure. The factory recommends shipping it at the actual set pressure. Question 2: Could adjusting the set pressure within the pressure range specified by the pressure testing institute affect the performance of the valve? Question 3: Are there any practical experiences, whether they are simple methods or crude approaches, to solve this problem? For example, set the pressure value higher, and also report a higher working pressure to the boiler inspection agency? (A suggestion I’ve heard)
The simplest solution is to install a burst disc in front of the safety valve; the two are connected in series, thereby preventing direct contact between the safety valve and the steam——Freed Steam Energy Saving.
For many of our corrosive and toxic materials, safety valves are used in series with rupture disks.
This post was last edited by nj1952 on 2017-7-14 21:43. (1) When the system’s steam consumption is low (such as at night or in the early morning), the safety valve may start to operate frequently, which can damage its sealing surface; the method described on page 2 is a commonly used approach. For the safety valve on the pipeline, a pressure reducing valve can be installed in front of its steam inlet ； For the steam entering the subsystem, a steam distribution cylinder can be installed to buffer the equilibrium pressure. (2) The factory’s suggestion to ship the product at the actual set pressure does not solve the problem. (3) \"Will adjusting the set pressure within the pressure range specified by the pressure testing institute affect the performance of the valve?\" Safety valves manufactured for use must be calibrated before installation, and this does not affect their performance. (4) “Are there any practical experiences, makeshift methods, or straightforward approaches to solve this problem?” For example, set the pressure value higher, and also report a higher working pressure to the boiler inspection agency? ”This approach is not recommended; it should be determined by the process engineering team based on the system pressure, and actions should not be taken blindly.