Gear pump is suitable for conveying medium temperature ≤170℃. Heavy oil, fuel oil, mechanical oil and other lubricating oil with a viscosity not more than 100mm²/s and other oils with similar properties. Generally used in petroleum, chemical, mechanical engineering and other occasions.
Gear pump classification
- According to the form of gear meshing, it can be divided into external gear type and internal gear type.
- According to tooth profile curve, it can be divided into involute tooth type and cycloid type.
- According to the form of tooth surface can be divided into: straight gear type (2CY gear pump), helical gear type (KCB gear pump), herringbone gear type, arc gear surface gear (YCB gear pump)
- According to the number of meshing gear, it can be divided into two gear type and multiple gear type
- according to the material: cast iron, cast steel or stainless steel gear pump.
- According to the gear series can be divided into: single-stage gear pump and multi-stage gear pump
Gear pump is simple in structure, convenient in processing, small in size, light in weight, and has strong self-priming ability, insensitive to oil pollution and other characteristics. So it is widely used. China's gear pump industry has two major competitive advantages: on the one hand, it has a low-cost competitive advantage; On the other hand, the rapid growth of domestic construction, petroleum. Petrochemical and environmental protection markets and major water diversion projects also provide important support for the development of pump industry. China's continuous growth of the market space is the prerequisite for the domestic gear pump industry to maintain advantages.
However, radial force imbalance, flow pulsation, noise, not easy to repair after wear and other shortcomings. So that the scope of use of gear pump is limited. Can't be used as variable pump.
Gear pump structural characteristics
- Good self-priming performance.
- Suction and discharge direction completely depends on the rotation direction of the pump shaft.
- pump flow is not large, continuous, but there is a pulse, noise; The pulsation rate is in the range of 11%~27%. Its ununiformity is related to the number and shape of gears. The ununiformity of helical gears is smaller than that of spur gears, and the ununiformity of herringbone gears is smaller than that of helical gears. The fewer the number of teeth, the higher the pulsation rate is.
- Theoretical flow rate is determined by the size and speed of the working parts, and has nothing to do with the discharge pressure; The discharge pressure is related to the load pressure.
- Simple structure, low price, less wearing parts (no need to set suction valve), impact resistance, reliable work, can be directly connected with the motor (no need to set gear motor).
- Friction surface, should not be discharged containing solid particles of liquid, should be discharged oil.
Gear pump is divided into two kinds of external engagement and internal engagement. The former is simple in structure, cheap in price and widely used; The latter manufacturing complex, less use, but because of its small size, light weight, uniform flow, high efficiency, long life. So suitable for some compact volume requirements, light weight requirements of the machine (such as aircraft). In order to improve the flow uniformity and operation stability of the pump, spiral gear or miter gear can be used, and the structure can be made into a single stage pump, double stage pump or double pump.
Compared with vane pump, plunger pump, gear pump efficiency is lower, oil suction height is generally not more than 500mm. Because the efficiency is low, the pressure is not too high, the flow is not large, so it is used for medium speed, the force is not large in the simple hydraulic system, sometimes also used as auxiliary hydraulic pump. General engineering machinery, mining machinery, agricultural machinery and machine tools and other industries can be used.