Classification of the screw pump screw pump belonging to the selected volume type rotor pump, which is composed of a plurality of pump displacement screw tooth and a pump sleeve sealing cavity formed to suction and discharge of liquid. Screw pump in two adjacent sealing chamber between the theory without leakage channel is referred to as strict sealing screw pump, and non strict sealing type screw pump.

The practical application and relevant documents according to the current display, screw covers a wide range of applications, it is characterized by a smooth flow, pressure pulsation is small, there is self absorption capacity, low noise, high efficiency, long life, small volume, reliable work. Outstanding advantages is the transmission medium without formation of eddy current, all sorts of medium can transport a wide range of viscosity, which can transport all kinds of lubricating viscosity or corrosive media, non Newtonian liquid can transport all kinds of viscosity, can the gas-liquid mixing conveying, solid-liquid mixed transportation. It is widely used in offshore platform engineering, petrochemical, electric power, shipping, mechanical and hydraulic systems, food, papermaking, sugar, military industry and sewage treatment and other industrial sectors. Sales manager to saying Germany al Wheeler company: "the world is without any medium, screw pump can not transport."

Said screw pump can transport any medium. Of course, not to say a kind of screw pump can transport all the media, but according to the characteristics and performance parameters of medium the number of requests can choose different types of screw pump. According to the number of the screw pump screw is usually divided into single screw pump, double, three and five screw pump, each have advantages, the popularization and application of screw pump must have a choice, only make full use of their own characteristics, to better realize the energy and material saving, increase benefit or meet some special requirements.

Pump set of single screw pump is composed of a non-metal elastic material (usually rubber) system to do, the inner hole spiral groove, a plurality of sealing cavity is formed between the metal screw with a spiral. Metal screw for eccentric rotation movement, make the seal cavity is composed of pump area of low pressure displacement to high pressure area, complete suction, discharge of fluid and the formation pressure of the whole process. In addition to the general media, single screw pump can be special medium conveying suspension and metal containing particles, including fiber etc.. In the treatment of sewage, slurry, the commonly used single screw pump, usually working pressure is not high.

Double screw pump is a non strict traditional sealing screw pump, the pump cover made by metal material has two phase cut cylindrical cavity, cavity two other meshing of screw, screw meshing gear shaped to form a plurality of sealing cavity in the pump cover and screw. Screw rotation movement, the seal cavity is composed of pump area of low pressure to high pressure area displacement. With a single head screw, also has the double screw pump double helix, the lubricating medium, if the helix angle is big enough, the main screw can directly drive the auxiliary screw. If the synchronous gear, in theory between two screw can not contact. The traditional double screw pump while non strict sealing, the working pressure is not high, but can be a variety of conveying medium viscosity range is very broad, non Newtonian fluids can transport all kinds of viscosity, can the gas-liquid mixing conveying, solid-liquid mixed transportation. Therefore, each industry is placed on it of great interest, especially in the petroleum, the chemical industry.

Three screw pump theory is strictly sealed screw pump. In the textbook, usually described as typical of the screw pump. Three screw pump is composed of a main screw metal pump sleeve to drive the two driven screw composition. Each screw two helix, in the pump sleeve and the screw rod is formed between the sealing cavity number, screw rotate, seal chamber by the pump area of low pressure to high pressure area displacement. Three screw pump of the maximum working pressure can reach 30MPa, the transmission medium is oil clean, non corrosive, special occasions can transport of high viscosity, non corrosive medium (such as: ink, glue and so on). Due to the three screw 1: 3: 5 ratio of the structure size and other reasons, medium viscosity range of three screw pump delivery Co., generally limited to lubricating medium.

Five screw pump is usually non strict sealing type screw pump. A main screw drive four auxiliary screw, each screw two helix. Because the pump cavity unit flow section is larger, so the medium conveying a large amount of. The five screw pump working pressure is usually in the 0.8MPa below, often in special occasions restricted installation size (such as: ships, ship) for oil pump.