Backpressure issue with the steam trap

The discharge from the trap is intermittent; before discharge, its pressure remains unchanged at nine kilograms, and it is only during discharge that a change occurs.

Principle: 1. The steam trap is installed between the steam heating equipment and the condensate return header. When driving, the bucket is at the bottom with the valve fully open. After entering the steam trap, the condensate flows to the bottom of the tank, filling the valve body and submerging it entirely; thereafter, the condensate is discharged to the return water header through the fully open valve. 2. Steam also enters the steam trap from the bottom of the tank, occupying the upper part of the tank and creating buoyancy. The barrel rises slowly, gradually moving the lever toward the valve seat until the valve is completely closed. Air and carbon dioxide gas gather at the top of the steam trap through the exhaust holes in the barrel. The steam discharged from the exhaust vents condenses due to the heat dissipation by the steam trap. 3. When the incoming condensed water begins to fill the tank, the tank starts to exert a pulling force on the lever. As the condensation level continues to rise, the force generated increases until it is sufficient to overcome the pressure difference and open the valve. 4. As the valve begins to open, the pressure difference acting on the valve disc decreases. The barrel body will drop rapidly, causing the valve to open fully. The non-condensable gases accumulated at the top of the steam trap are discharged first, followed by the condensate. As the water flows out of the tank, it carries the dirt with it and out of the drain valve. As the condensate is discharged, steam begins to flow back into the steam trap, and a new cycle starts.

The pressure should be between 8 and 9; the pressure loss of a strainer is very low – it’s just an ordinary valve, so it won’t have a pressure loss of up to 8 kgf.

The back pressure should be related to the pressure control of the steam trap’s piping, and the magnitude of the pressure difference affects the amount of steam drained

The heat exchanger uses 9at steam, but this does not mean that there is a pressure of 9at before the drain valve. When the load is low while the heat exchanger is being heated, the pressure of the condensate water will be relatively low; you can use a pressure gauge to verify this if you doubt it.

1. We have a heater; the pressure at the distribution station is 0.6 MPa, while it drops to 0.3 MPa before reaching the heat exchanger； 2. Generally, the pressure in front of the steam trap can be maintained at the same level as the pressure of the heating steam entering; the pressure behind the trap depends on the pressure drop associated with the transfer of condensate water ； 3. Since phase change heat release occurs within the heater, water and vapor are in a two-phase equilibrium state. :lol

1. If the condensate is recovered and reused as boiler water, the back pressure of the steam trap is the pressure difference between the steam side and the condensate system side. 2. If emission occurs only at the site, the back pressure can be considered as the pressure on the steam side.

The back pressure of a steam trap consists of the height increase behind the valve and the pressure in the condensate return pipe; its own pressure drop is very small. You should provide details about the specific conditions in which it will be used on site, as well as whether you intend to utilize the back pressure for returning water or for some other purpose. This will enable others to assist you better.

The back pressure is determined by the pipeline system downstream of the valve; if it is discharged directly, it is at atmospheric pressure, while if it is recycled, it is specified during the design phase.

It is related to the pressure of the condensate water system; if condensate water is recovered, it is roughly the same as the pressure in the condensate recovery tank (with some head pressure added). If steam leaks into the condensate system, the pressure will be much higher. Typical mechanical traps have very low pressure drops and can withstand high pressures. For other types, if the back pressure increases, water cannot flow out.