What is a Hose Pump?

Hose pumps belong to the category of peristaltic pumps. Peristaltic pump is a type of rotary positive displacement pump. It is named because it works similarly to the gastrointestinal tract to transport gas, solid and liquid three-phase media.

Hose pumps have been used in industry for many years, and the earliest original designs of hose pumps even date back more than half a century. Hose pumps were first used by firefighters in Connecticut to pump lime slurry.

There is no strict distinction between hose pumps and peristaltic pumps. Generally speaking, peristaltic pump refers to small flow (in ml / min) and low outlet pressure (not more than 3kg / cm2), which is mostly used in the field of health and laboratory measurement. The hose pump refers to large flow (up to 80 m / h) and high output pressure (up to 16 kg / cm2), which is mostly used for large flow transmission and metering in industrial occasions.

The most important thing for designers and users of hose pumps is their ability to transport highly abrasive media. It has no valve, no seal, and the only part in contact with the medium is the inner cavity of the rubber hose, and the rotor of the compression hose is completely independent of the medium.

In addition, hose pumps have many unique features: no other pump has better self-priming ability than hose pumps, and can almost produce a perfect vacuum to suck liquid; transport gas-containing liquids and foam liquids without air resistance; Conveying high-viscosity, shear-sensitive media is also a strength; a fixed displacement per revolution is independent of the outlet pressure and is a natural metering pump. These advantages make hose pumps more and more widely used in gold smelting, non-ferrous smelting, chemical, mining, food processing, brewing, ceramics, water treatment and other industries.

The life of a high-quality hose pump is 7-10 years. The biggest challenge is the hose of the hose pump. It is the core component of the hose pump. Its life is directly related to the use cost of the pump. It can be said that the design of the hose pump is based on maximizing the life of the hose.

The hose pump is a rotor type positive displacement pump. It works by the elasticity of the flexible element (hose) in the pump and the rollers or shoes on the rotor. Its working principle is shown in Figure 7-96.

Hose pumps are designed in a variety of ways, but there are only three ways to distinguish them by compressing the hose:

The first is a sliding shoe design (sliding shoe hose pump). The hose is U-shaped or bow-shaped in the pump cavity; two or more slide shoes (sliders) are fixedly mounted on the runner (rotary arm), and the hose is compressed in a sliding manner. The roller compresses the hose two or more times per revolution (depending on the number of shoes). Because the frictional heat is generated, in order to ensure normal operation, about half of the pump cavity is filled with lubricant. On the one hand, in order to reduce the friction coefficient, the more important is to transfer the generated frictional heat to the pump body and discharge it outside the pump to ensure the Normal operation. The advantage of this sliding shoe design is that it can reach higher outlet pressures (up to 1.6Mpa).

The second design is to change the slide shoe to a small-diameter pressure roller (multi-pressure roller hose pump) based on the slide shoe design. The rotary arm rotates once, and the pressure roller also compresses the hose 2 or more times (depending on the number of pressure rollers). Compared with the sliding shoe design, this pressure roller design reduces the damage to the hose and generates much less frictional heat; it extends the hose life up to 20% (in revolutions) ). Correspondingly reduced starting torque and running torque, reducing energy consumption. However, the number of compressions and frictional heat per second or more still limits the speed. A two-inch pump can only run continuously at a maximum of 40-50 rpm under high pressure.

The third design is to form a full circle in the pump cavity and use a large diameter pressure roller to compress the hose. This can be said to be a major breakthrough in the development history of hose pumps.

The characteristics of the hose pump are as follows:

a) Since there is no mechanical seal and gland packing, there is no need to worry about leakage of the sealing part.

b) Since there is no sealed part, it can be run dry and used as a vacuum pump.

c) Because the fluid only passes through the special hose, the impeller, rotor, cylinder and other operating parts do not contact the liquid and do not stir and foam, so it can be directly transported in the original state.

d) It can be transported in any direction of discharge and suction. Therefore, the fluid remaining in the discharge pipe can be easily drained by reversing.

e) The parts in contact with liquid are only rubber, which has good abrasion resistance and low-speed operation, so it is suitable for slurry transportation. ^[2]