German HPI pump HPI model HPI price

HPI pumps are rotary pumps that transport liquids or increase their pressure by relying on the change and movement of the working volume formed between the pump cylinder and the meshing gears. Two enclosed spaces are formed by two gears, the pump body, and the front and rear covers. When the gears rotate, the volume of the space on the disengaging side increases from small to large, creating a vacuum that draws in the liquid. The volume of the space on the meshing side decreases from large to small, squeezing the liquid into the pipeline. The suction chamber and the discharge chamber are separated by the meshing line of the two gears. The pressure at the discharge port of the gear pump depends entirely on the magnitude of the resistance at the pump outlet.

HPI pump structural features

1) Simple structure, low price; 2) Low operational requirements, wide application; 3) The end covers and the slots between the gear teeth form many fixed sealed working chambers, so it can only be used as a positive displacement pump. The gears adopt the double circular arc sine curve tooth profile, an advanced technology from the international nineteen-nineties. Compared with involute gears, its most prominent advantage is that there is no relative sliding on the tooth flank during the gear meshing process, resulting in no wear on the tooth surface, smooth operation, no fluid trapping, low noise, long service life, and high efficiency. This pump breaks free from the constraints of traditional design, bringing gear pumps into a new realm in terms of design, production, and use. The pump is equipped with a differential pressure safety valve for overload protection; the full return pressure of the safety valve is 1.5 times the rated discharge pressure of the pump. It can also be adjusted according to actual needs within the allowable discharge pressure range. However, this safety valve cannot be used as a pressure reducing valve for long-term operation; a pressure reducing valve can be installed separately if needed. The shaft end seal of this pump is designed in two forms: one is mechanical seal, and the other is packing seal, which can be determined based on specific operating conditions and user requirements.

HPI pump drive unit

The gear pump is driven by an independent motor, which can effectively block upstream pressure pulsations and flow fluctuations. The pressure pulsation at the gear pump outlet can be controlled within 1%. Adopting a gear pump on an extrusion production line can increase the flow output speed and reduce the shear and residence time of materials in the extruder. External meshing gear pumps are the most widely used type of gear pump; generally, when referring to gear pumps, it usually means external meshing gear pumps. Its structure is shown in Figure 5-14, mainly consisting of the driving gear, driven gear, pump body, pump cover, and safety valve. The sealed space formed by the pump body, pump cover, and gears is the working chamber of the gear pump. The shafts of the two gears are respectively installed in the bearing holes on the two pump covers. The driving gear shaft extends out of the pump body and is rotated by the motor. External meshing gear pumps have a simple structure, light weight, low cost, reliable operation, and wide application range. When the gear pump is working, the driving gear rotates with the motor and drives the driven gear to rotate. When the meshing teeth on the suction chamber side gradually separate, the volume of the suction chamber increases, the pressure decreases, and the liquid in the suction pipe is drawn into the pump. The sucked liquid is pushed by the gears in the tooth slots along two paths to the discharge chamber. After the liquid enters the discharge chamber, due to the continuous meshing of the teeth of the two gears, the liquid is squeezed and enters the discharge pipe from the discharge chamber. As the driving gear and driven gear rotate continuously, the pump can continuously suck in and discharge liquid. A safety valve is installed on the pump body. When the discharge pressure exceeds the specified pressure, the transported liquid can automatically push open the safety valve, allowing the high-pressure liquid to return to the suction pipe. Internal meshing gear pumps consist of a pair of mutually meshing internal gears, a crescent-shaped piece between them, and a pump shell. The function of the crescent-shaped piece is to separate the suction chamber and the discharge chamber. When the driving gear rotates, a partial vacuum is formed where the gears disengage, and the liquid is sucked into the pump, filling the spaces between the teeth in the suction chamber. Then, it enters the discharge chamber along the inner and outer sides of the crescent-shaped piece via two paths. Where the teeth enter meshing, the liquid existing between the teeth is squeezed and sent into the discharge pipe. In addition to having self-priming capability and flow rate independent of discharge pressure, gear pumps have no suction or discharge valves on the pump shell, featuring simple structure, uniform flow, and reliable operation. However, they have low efficiency, high noise and vibration, and are prone to wear. They are mainly used to transport various oils that are non-corrosive, free of solid particles, and have lubricating properties. The temperature generally does not exceed 70 ℃, such as lubricating oil and edible vegetable oil. The general flow range is 0.045～30ms/h, the pressure range is 0.7—20MPa, and the operating speed is 1200—4000r/min.

HPI pump troubleshooting

1) Fault phenomenon: Pump cannot discharge material. Fault causes: a, reverse rotation direction; b, suction or discharge valve closed; c, no material at inlet or pressure too low; d, viscosity too high, pump cannot bite material. Countermeasures: a, confirm rotation direction; b, confirm whether valves are closed; c, check valves and pressure gauge; d, check liquid viscosity to see if flow appears proportional to speed when running at low speed; if there is flow, then inflow is insufficient. 2) Fault phenomenon: Insufficient pump flow. Fault causes: a, suction or discharge valve closed; b, low inlet pressure; c, blocked outlet pipeline; d, packing box leakage; e, speed too low. Countermeasures: a, confirm whether valves are closed; b, check whether valves are open; c, confirm whether discharge volume is normal; d, tighten; if massive leakage affects production, stop operation and dismantle for inspection; e, check actual pump shaft speed. 3) Fault phenomenon: Abnormal sound. Fault causes: a, large coupling eccentricity or poor lubrication; b, motor failure; c, gearbox abnormality; d, poor installation at shaft seal; e, shaft deformation or wear. Countermeasures: a, align or fill with grease; b, check motor; c, check bearings and gears; d, check shaft seal; e, stop and dismantle for inspection. 4) Fault phenomenon: Excessive current. Fault causes: a, excessive outlet pressure; b, melt viscosity too high; c, poor assembly of shaft seal; d, shaft or bearing wear; e, motor failure. Countermeasures: a, check downstream equipment and pipelines; b, test viscosity; c, check shaft seal and adjust appropriately; d, stop and check, manually turn to see if it is too heavy; e, check motor. 5) Fault phenomenon: Pump stops suddenly. Fault causes: a, power outage; b, motor overload protection; c, coupling damage; d, excessive outlet pressure, interlock reaction; e, abnormal biting inside pump; f, shaft and bearing adhesion/seizure. Countermeasures: a, check power supply; b, check motor; c, open safety cover and manually turn to check; d, check instrument interlock system; e, after stopping, confirm by manually turning forward and reverse; f, confirm by manually turning. 6) Fault phenomenon: Seal oil leakage. Causes: a, shaft seal not adjusted properly; b, sealing ring worn resulting in large clearance; c, mechanical seal dynamic and static ring friction surfaces damaged; d, spring relaxation. Countermeasures: a, readjust; b, tighten gland bolts appropriately or replace sealing ring; c, replace dynamic and static rings or regrind; d, replace spring.

Weidou Intelligent Technology professionally sells German HPI gear pumps, HPI gear pumps, HPI diaphragm pumps, HPI centrifugal pumps, HPI piston pumps, HPI vacuum pumps, HPI screw pumps, HPI submersible pumps, HPI peristaltic pumps, HPI lubrication pumps, HPI vane pumps, HPI metering pumps, HPI hand pumps, HPI drum pumps, HPI lobe pumps, HPI booster pumps, HPI liquid pumps, HPI air pumps. Original imports from Germany. Welcome customers to inquire and order.