Everything is equipped with Three screw pump In all systems, it is required to equip a safety valve (pressure relief valve) at the pump outlet. The standard low-pressure series products of IMO AB pumps are equipped with built-in safety valves to provide maintenance for the pump during overpressure operation.

However, the built-in safety valve can only maintain the pump for temporary overpressure supply. It can neither be used as system pressure control equipment nor as flow conditioning equipment. Under the condition of pump overpressure, the built-in safety valve will be opened, and the temperature will rise when the fluid flows back through the safety valve and circulates in the pump body. The fluctuation of temperature rise is in direct proportion to the set pressure of the safety valve and the return fluid percentage.

In addition to pumping low viscosity fluid, the pump can run for a long time under the condition of up to 50% reflux without any harm. If the pump is expected to operate under the condition of more than 50% reflux, it is necessary to explain to the technicians of Shanghai Kunjin Electromechanical Co., Ltd. in particular, so that the valve can be accurately planned by closely monitoring the pump body temperature according to this specific condition.

When the flow is less than 50 m3/h, if the fluid viscosity and temperature are within the allowable range of the pump, the longest time the pump can operate under 100% reflux condition cannot exceed 3 minutes. When the flow is greater than 50 m3/h, the pump can only allow 100% reflux for 30 seconds. When the safety valve is open, the noise will increase. This can also be used to determine whether the system is now overpressure.

If there is an independent safety valve at the pump outlet, its setting value should be high enough not to disturb the built-in safety valve of the pump. When two pumps operate in parallel, the setting of safety valve shall also prevent mutual disturbance.

When adjusting the set pressure of the safety valve:

L Turn the safety valve clockwise to the maximum;

L Adjust the valve on the pipeline behind the pump until the required pressure value;

L Turn the safety valve counterclockwise until the pressure gauge shows that the pressure is about to drop;

L Open the valve on the pipeline behind the pump completely

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