Why should the hot oil pump be preheated and matters needing attention before starting?

Why should the hot oil pump be preheated and matters needing attention before starting?

Why should the heat pump be preheated before starting? What should I pay attention to when preheating?

If the hot oil pump is started without preheating, the hot oil will quickly enter the cold pump body, which will cause the pump body to be heated unevenly. The mouth ring and the sealing ring of the rotor are stuck; forcible start will cause wear, shaft holding, and shaft breakage accidents.

If the oil with high viscosity is not preheated, the oil will condense in the pump body, resulting in no amount of oil after starting, or the motor will trip due to the large starting torque.

Due to insufficient preheating, the thermal expansion of the pump will be uneven, and the static sealing point will leak. For example, leakage of the outlet and inlet flanges, the large cover flange of the pump body, and the balance pipe may even cause serious accidents such as fire and explosion.

What should be paid attention to when preheating the hot oil pump?

The preheating process should be correct. The general process is: pump outlet pipeline → inlet and outlet cross line → preheating line → pump body → pump inlet.

The preheat valve should not be opened too far to prevent the pump from being reversed.

Generally, the preheating speed of the pump body should not be too fast, and should be less than 50℃/h. Under special circumstances, the preheating speed can be accelerated by adding steam and hot water to the pump body.

During preheating, the crank should be turned 180° every 30 to 40 minutes to prevent the pump shaft from bending due to uneven heating up and down.

The cooling water system of the bearing housing and pump seat should be opened to protect the bearing and shaft seal.