Application range of gear pumps and screw pumps

Our company uses screw pumps to pump tar and gear pumps to pump high-viscosity materials! Since the material viscosity of the two pumps is very high, a safety valve should be installed at the pump outlet!

What is the difference? In which case a gear pump is used and in which case a screw pump is used?

Regarding the similarities and differences between the use of screw pumps (hereinafter referred to as three-screw pumps) and gear pumps, I would like to express some of my humble opinions. Please do not laugh.: Due to the different design principles and structural characteristics of screw pumps and gear pumps, screw pumps have the following characteristics compared to gear pumps:: 1. High energy saving efficiency. 2. It has the characteristics of small pressure pulsation and stable delivery flow. 3. Low noise (about 40 decibels). 4. It works smoothly and reliably and allows high speed. 5. Long service life. 6. Characteristics such as strong self-priming ability. Compared with screw pumps, gear pumps have the following characteristics: 1. Small installation space. 2. Easy maintenance. 3. Economical and practical. 4. Allow high pressure delivery (screw pump currently can only reach 6.3MPA in China) The following points should be considered by customers:: 1. The one-time investment of the screw pump is relatively high, while the gear pump is relatively economical. However, considering the one-time investment of the pump, maintenance costs, electricity costs and elimination costs, the costs of the two are equivalent under the same conditions. 2. For the transportation of high-viscosity materials (heavy oil, asphalt, etc.), I personally think that the screw pump (heating pump) has the advantage over the twin-screw pump.: Compared with three-screw pumps and gear pumps, twin-screw pumps not only have the characteristics of three-screw pumps, but also overcome the shortcomings of three-screw pumps and gear pumps that cannot be idle. They are also an ideal choice for the mixed transportation of oil and gas and the transportation of light oil. Currently, twin-screw pumps are commonly used in oil fields and marine pumps to meet the needs of large flow rates and mixed transportation of oil and gas. Of course, the price of the twin-screw pump is also higher. This is just my humble opinion. Please feel free to enlighten me.

In fact, there are not many application differences between gear pumps and screw pumps. For heavy oil applications, either a gear pump or a screw pump can be used. It mainly depends on the required pressure. Generally, the outlet pressure of the screw pump is higher than that of the gear pump. For high viscosity materials such as ABS, polyester, etc., gear pumps have many advantages over screw pumps.

For viscous materials such as heavy oil, both gear pumps and screw pumps can transport. In terms of leakage rate, screw pumps are better.； In terms of operation, the screw pump is also better. ； However, generally heavy oil contains impurities, which have a great impact on the screw pump. In addition, if the pump is not opened correctly, the screw pump can be easily damaged, resulting in the loss of pressure. Cost-wise, gear pumps are cheap and run just fine. Our heavy oil was originally designed as a screw pump. After running for a period of time, the pressure was always lost. Later, a gear pump was replaced. The operation was better, but the replacement was more frequent. But after all, the gear pump is still cheaper. Please refer to it.

Thanks for everyone's suggestions, I've learned a lot.

I agree with the fourth floor's point of view. I personally prefer three-screw pumps. Many occasions where gear pumps were originally used are now using three-screw pumps.

For example, for things like making sauce and engine oil, you can only use a screw pump.