Compact Dry Scroll Pump

Compact Dry Scroll Pump is also called scroll pump, regeneration pump, etc. It is called vortex pump because it sucks and discharges liquid by the action of vortex motion caused by the rotation of impeller. According to different types, compact dry scroll pump can be divided into single-stage scroll pump, centrifugal scroll pump, stainless steel scroll pump and other scroll pump.

At present, the flow rate of the general compact dry scroll pump is 0.2 ~ 27m3 / h. The working principle of the general compact dry scroll pump when the prime mover drives the impeller to rotate in the pump through the shaft, the liquid enters the flow passage from the suction population, and is impacted by the centrifugal force of the rotating impeller, falling into the surrounding annular flow passage, so that the liquid rotates in the flow passage. Because every liquid particle is affected by centrifugal force, the liquid inside the impeller is more affected by centrifugal force, while the liquid inside the runner is less affected by centrifugal force. Because of the different magnitude of centrifugal force, the liquid makes longitudinal vortex motion. The liquid circulates through the passage between the blades many times in the passage by the longitudinal vortex. Every time the liquid passes through the passage between blades, the head will be increased once, and finally the liquid will be squeezed out and discharged from El. After the liquid is discharged, a local vacuum will be formed in the passage between the blades, and the liquid will continuously enter the impeller from the suction port, and repeat the above movement process. In this way, the scroll pump sucks the liquid at the same time and discharges the liquid at the same time, so as to work continuously. It can be seen from the working principle of general scroll pump that it is like the function of multi-stage centrifugal pump. Each blade passage is equivalent to one stage, and the energy increases once the liquid passes through the passage. Therefore, the head of general vortex pump is 2-5 times larger than that of centrifugal pump under the same impeller diameter, so it is a high head and small flow pump. Compared with the centrifugal pump with the same performance, the volute pump is smaller and lighter; compared with the scroll pump with the same head, the scroll pump has much smaller size and simpler structure. So the general scroll pump has the advantages of simple structure, compact, small volume, light weight and low cost

Working principle of compact dry scroll pump: the impeller is a disc of equal thickness, and there are many radial blades on both sides of its outer edge. There is an annular flow passage with the same section on the pump shell corresponding to the blade. The whole flow passage is divided into suction and discharge by a tongue, which are respectively connected with the suction and discharge pipes of the pump. When the impeller rotates, under the action of centrifugal force, the circular velocity of the liquid in the impeller is greater than that in the flow passage, so the “circular flow” is formed. Since the liquid from the suction to the discharge follows the impeller, the combination of the two movements results in the liquid producing the same “longitudinal vortex” as the impeller.

When the liquid in the pump rotates with the impeller, it will produce a certain centrifugal force, which will be thrown into the circular passage in the pump housing, and forced to return under the restriction of the passage shape, and then enter the other passage behind from the root of the blade. Therefore, the movement trace of liquid between the blade and the annular passage is a forward spiral for the static pump shell, and a backward spiral for the rotating impeller. scroll pump is named for this kind of vortex motion of liquid. The liquid can enter into the blade for several times continuously to obtain energy until it is finally discharged from the discharge outlet.

The compact dry scroll pump works like multistage centrifugal pump, but there is no energy conversion device like the volute or guide vane of centrifugal pump. The compact dry scroll pump mainly transmits the energy to the liquid through the way of continuous work for many times, so it can produce high pressure. In the process of energy transfer, due to the multiple impacts of the liquid, the energy loss is large, and the efficiency of the pump is low, generally 20-50%.

The compact dry scroll pump is only suitable for the occasions requiring small flow (1-40m3 / h) and high lift (up to 250m), such as fire pump, gasoline pump on aircraft tanker, small boiler feed pump, etc. The compact dry vortex pump can transport liquid with high volatility and gas, but it should not be used to transport thick liquid with viscosity greater than 7 PA · s and unclean liquid with solid particles.