Regarding the modification of the pump
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Has there been any experience in modifying pumps in actual production? Let’s discuss and share!
We modified the impeller of the pump to change its suction inlet angle, **which improved the pump’s performance. But this is only possible if the motor power of the pump is sufficient.
The poster is wondering whether the modifications are carried out by the user themselves or by the manufacturer. Generally, users carry out the modifications themselves, especially for relatively simple tasks such as changing the diameter of the impeller, modifying the shaft seals, or altering the couplings. If major changes to the pump’s performance are desired, then it should be the manufacturer who carries out those modifications.
Well, let me tell one too! In our methanol plant, when the pumps were first put into operation, they were equipped with flushing water for the mechanical seals. Later, it was found that for some pumps, such flushing was not necessary depending on the process conditions; so it was discontinued for most of those pumps, which saved a lot of trouble!
There are many areas that can be modified in centrifugal pumps: 1. Modification of the impeller (cutting the impeller, replacing it with a three-dimensional flow impeller, changing the material of the impeller, etc.)； 2. Modification of sealing systems (changing from packing seals to mechanical seals, changing from single-face mechanical seals to tandem or double-face mechanical seals, and changing mechanical seals to dry gas seals) ； 3. The lubrication system has been changed from thin oil lubrication to oil mist lubrication ； 4. Modification of the oil seal (replacing the skeleton seal with a magnetic oil seal or a mechanical seal) ； 5. Replace ordinary centrifugal pumps with magnetic pumps or shielded pumps, etc.
Let me talk about our modifications to the ultra-high pressure plunger pump: the outlet pressure is too high, at 270 MPa, and the spare parts are all imported. The valve balls used in the outlet check valves were originally made of tungsten carbide, with a diameter of 6.3 mm; there was more than 500 of them per unit. They were expensive, very hard and heavy, did not function properly, and over time they would get stuck in the valve seat. Later, we switched to domestic cerametal, which increased the service life by 5 times and cost only one-tenth of the foreign version.
Sealing modification of the pump: replacing the packing seal with a mechanical seal
There are two types of pump modifications: replacement and retrofitting of old pumps. The update is mainly due to the pumps no longer meeting the requirements of the new process conditions, or high maintenance frequencies and high consumption of spare parts. The renovation of old pumps mainly involves modifying the pump’s seals based on its operating conditions. We also changed the material of the impeller for this pump
There are modifications to the impeller and to the material. It works very well.
We modified the outlet check valve of the high-pressure ammonia pump; due to severe corrosion at the sealing point between the outlet check valve and the cylinder body, we changed the sealing method from upper sealing to lower sealing, and the result was even better than before
Several pumps in our catalytic unit have been modified from self-flushing to oil-sealing flushing! !