【Q&A Question 333】December 17, 2017
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【Q&A Question 333】December 17, 2017: What issues should be considered when preheating a pump? The correct preheating sequence is: pump outlet pipeline → preheating valve → pump body → pump inlet valve. Do not open the preheating valve too wide to prevent the pump from rotating in reverse. The preheating rate shall not exceed 50°C/h, and the turbine shaft should be rotated during preheating. The cooling water for the bearing housing, pump base, and end face seals must all be turned on to protect the bearings and shaft seals. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) For management purposes, if you need to view content from a few days ago, please access it through the summary post below. 2017 Q&A Summary Thread (updates have started) https://bbs.hcbbs.com/thread-1657793-1-1.html 2017 Daily Question Summary Thread (updates have started) https://bbs.hcbbs.com/thread-1657794-1-1.html 2017 Daily Image Summary Thread https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1875160 2017 LNG Version Daily Question Catalog https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1804162 2016 Q&A Summary Thread (updates completed) https://bbs.hcbbs.com/thread-1597792-1-1.html
When preheating the pump, pay attention to the following points: 1. The preheating procedure must be correct. Generally, the pump outlet pipeline preheats the pump inlet through a preheating bypass valve that spans the inlet and outlet. Do not open the preheating valve too much to prevent the pump from reversing. 2. Preheating is carried out at a rate of 50°C/h; in emergency situations, the preheating speed can be increased by taking appropriate measures (such as using steam to blow on the pump body to assist with preheating). If you go too fast, the pump body will heat up rapidly, leading to leaks at the various joints and the rotor bending or getting stuck. 3. During preheating, the pump shaft should be rotated; generally, it should be rotated every 30 to 45 minutes to prevent bending of the main shaft and to help remove gases from within the pump. 4. The cooling water for the bearing housings, pump bases, and end-face seals must all be turned on to protect the shafts and bearings
①The preheating process is correct. Generally, the pump outlet pipeline preheats the pump inlet through a preheating bypass valve that spans the inlet and outlet. Do not open the preheating valve too much to prevent the pump from reversing. ②Preheating is carried out at a rate of 50°C/h; in emergency situations, the preheating speed can be increased by taking appropriate measures (such as using steam to blow on the pump body to assist with preheating). If you go too fast, the pump body will heat up rapidly, leading to leaks at the various joints and the rotor bending or getting stuck. ③The shaft should be rotated during preheating, usually once every 30 to 45 minutes, to prevent bending of the main shaft and to help remove gases from within the pump. ④The cooling water for the bearing housing, pump base, and end face seals must all be turned on to protect the shaft and bearings.
The preheating valve should not be opened too wide to prevent the pump from reversing. The preheating rate of the pump body generally should not be too fast; it should be less than 50°C/h. In special cases, the preheating process can be accelerated by introducing steam or hot water into the pump body
① Centrifugal pumps must not be operated without liquid under any circumstances, to prevent damage to the components. ② The hot oil centrifuge must be preheated before starting, to avoid accidents caused by a large temperature difference between cold and hot substances. ③ After the centrifugal Chestnut is started, it is not allowed to operate for an extended period of time with the outlet valve closed. ④ Under normal conditions, centrifugal pumps must not use manual valves to regulate flow to avoid cavitation. ⑤ Outdoor liquid-phase oil pumps must be pre-heated before being started in winter. ⑥ After starting the pump, it is necessary to immediately check the motor current, the pressure at the pump outlet, and the flow rate, as well as the temperature and vibration levels of the motor and the pump body. It is also important to check for any abnormal noises.
①The preheating process is correct. Generally, the pump outlet pipeline preheats the pump inlet through a preheating bypass valve that spans the inlet and outlet. Do not open the preheating valve too much to prevent the pump from reversing. ②Preheating is carried out at a rate of 50°C/h; in emergency situations, the preheating speed can be increased by taking appropriate measures (such as using steam to blow on the pump body to assist with preheating). If you go too fast, the pump body will heat up rapidly, leading to leaks at the various joints and the rotor bending or getting stuck. ③The shaft should be rotated during preheating, usually once every 30 to 45 minutes, to prevent bending of the main shaft and to help remove gases from within the pump. ④The cooling water for the bearing housing, pump base, and end face seals must all be turned on to protect the shaft and bearings.
①The preheating process is correct. Generally, the pump outlet pipeline preheats the pump inlet through a preheating bypass valve that spans the inlet and outlet. Do not open the preheating valve too much to prevent the pump from reversing. ②Preheating is carried out at a rate of 50°C/h; in emergency situations, the preheating speed can be increased by taking appropriate measures (such as using steam to blow on the pump body to assist with preheating). If you go too fast, the pump body will heat up rapidly, leading to leaks at the various joints and the rotor bending or getting stuck. ③The shaft should be rotated during preheating, usually once every 30 to 45 minutes, to prevent bending of the main shaft and to help remove gases from within the pump. ④The cooling water for the bearing housing, pump base, and end face seals must all be turned on to protect the shaft and bearings.
The preheating sequence is correct: pump outlet pipeline → preheating valve → pump body → pump inlet valve. Do not open the preheating valve too wide to prevent the pump from reversing. The preheating rate shall not exceed 50°C/h, and the turbine shaft should be rotated during preheating. The cooling water for the bearing housings, pump bases, and end face seals must all be turned on in order to protect the bearings and shaft seals
The preheating speed should not be too fast; the temperature should be kept at 30 degrees per hour or less； Be careful not to run the pump in reverse ；
①The preheating process is correct. Generally, the pump outlet pipeline preheats the pump inlet through a preheating bypass valve that spans the inlet and outlet. Do not open the preheating valve too much to prevent the pump from reversing. ②Preheating is carried out at a rate of 50°C/h; in emergency situations, the preheating speed can be increased by taking appropriate measures (such as using steam to blow on the pump body to assist with preheating). If you go too fast, the pump body will heat up rapidly, leading to leaks at the various joints and the rotor bending or getting stuck. ③The shaft should be rotated during preheating, usually once every 30 to 45 minutes, to prevent bending of the main shaft and to help remove gases from within the pump. ④The cooling water for the bearing housing, pump base, and end face seals must all be turned on to protect the shaft and bearings.