Application Characteristics and Reasonable Selection Method of Screw Pumps
Screw pumps are one kind of characteristic rotary pumps, which have small flow and large pressure, high operating efficiency and long life. This paper mainly introduces the application characteristics of screw pumps, the reasonable selection and application methods.
1. Application characteristics of screw pumps
The screw pump is a special rotary pump. Its working performance mainly depends on the meshing of the two synchronous screw rods and the generated medium conveying effect. The screw pump has the characteristics of small flow and large pressure, large flow and small pressure, high operating efficiency and long life.
1.1 Small flow and large pressure: Screw pump H of parallel flow structure is suitable for conveying medium with low flow and large pressure. Its delivery range is relatively wide, and it can absorb suction pressure of-0.25 MPa. The pump can also be used for the transportation of liquids with high viscosity and solid particles content, and for the transportation of stable and unstable abrasive, high temperature and corrosive liquids.
1.2 Large flow and small pressure: The screw pump series of reverse flow structure is suitable for conveying medium with large flow and small pressure, and the flow rate can reach hundreds of cubic meters per hour. The delivery range is wide and pressure can go up to 2MPa.
1.3 High operating efficiency: Under normal working conditions, the driving power of the screw pump is only 1/4-1/5 1/4 to 1/5 of other types of pumps with the same flow and pressure.
1.4 Long service life: The working life of screw pump is generally more than 8000 hours, and it can be prolonged by using advantageous material and proper operation maintenance.
2. Reasonable selection and application method of screw pumps
2.1 The reasonable selection of screw pumps should consider the following aspects:
(1) First of all, it is necessary to understand the transportation medium, including its nature (corrosive, non-corrosive, density, viscosity, etc.), working pressure, temperature, flow and concentration of impurities, as well as other requirements (oxygen content, sediment content, performance requirements).
(2) Select the type and model with proper structural form according to the conditions of the liquid transportation. In general, multi-section screw pumps are used for large flow and small pressure, and parallel screw pumps are used for small flow and large pressure.
(3) Determine the material of the pump considering the performance of the medium, temperature, corrosiveness and other comprehensive factors.
(4) Determine the speed and others according to the flow and pressure requirements of the medium.
2.2 The reasonable application of screw pumps should consider the following aspects:
(1) Pay attention to the use environment of the pump. Do not place it in places with violent vibration, dust, petrochemical and explosive media. The temperature of the medium should not exceed 85 ℃.
(2) The suction pressure of the pump should not be less than 0.25 MPa, and the pressure should not exceed 2.5MPa.
(3) Start the no-load pump for a few minutes to confirm its normal operation and then increase the load in small increments. When the temperature is too high, flushing or cooling should be used.
(4) Always check the pump system for any damage or looseness. Carefully observe the operation of the pump system and adjust the parameters or pressure in a timely manner to avoid harming the pump or the pipeline.
(5) Regular maintenance is necessary for screw pumps. The specific maintenance should be carried out according to the instructions of the pump manufacturer or experienced personnel.
3. Summary
Screw pumps can be used in petroleum, chemical, forestry, paper-making, pharmaceutical, environmental protection and other industries. The application of screw pumps can save energy, reduce noise and improve operating conditions due to its small size, high efficiency, long service life, wide delivery range and other advantages. This paper introduces the application characteristics of screw pumps, as well as the reasonable selection and application methods to help users properly select and use screw pumps in accordance with the actual conditions.
