Safety valve discharge
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This post was last edited by watermind on 2019-9-2 08:00. The vapor-liquid separation tank of a liquid ring pump is equipped with two safety valves. I would like to ask: why is the discharge outlet of one of these safety valves connected back to the separation tank?
Once the safety valve has released pressure or there is internal leakage, residue will accumulate at the lowest point downstream of the safety valve, and this residue needs to be drained.
Is it related to the properties of the medium, as well as the manufacturing process?
Behind the manual valve located after the safety valve, there is a tee; one branch leads to the tank, while the other branch leads somewhere else. That must be the ultimate outlet for the safety valve. The branch that leads to the tank is likely a bypass or what’s known as a manual vent.
Connecting a safety valve in this manner is completely incorrect and not permitted: 1. A stop valve installed below the safety valve must remain open at all times, must be sealed with lead, and requires approval from the person in charge of safety at the facility using it； 2. It is also not allowed to have a valve at the outlet of the safety valve; if the medium cannot be released into the atmosphere, it must be directed to a buffer tank or a treatment device, and there must be no shut-off valve in between. 3. The safety valve has not been calibrated; no calibration mark is visible in the image.
You can learn *new knowledge every day, and encounter new things every day. Let’s take a look first, showing confusion...
What was said on the 4th floor is correct; I went to the scene again and there are other exits as well； The comments on the 5th floor were very professional; thanks!
This takes into account the discharge from safety valves in gas-liquid two-phase flow situations, but such an approach is not permitted. Generally, the discharge pipes and pipe racks for safety valves in gas-liquid two-phase flow systems must be carefully designed; a liquid separation tank can be used. If the liquid cannot be discharged arbitrarily, the outlet pipe should lead horizontally into the liquid separation tank, or a drain pipe should be installed. In some cases, a shut-off valve can be added at the outlet of the safety valve. But it must be a LO valve; however, this is not the case.