German GL pump GL model GL price

The most basic form of the GL pump consists of two gears of identical size meshing and rotating within a closely fitted housing. The interior of this housing resembles the figure "8", with the two gears installed inside; the outer diameter and sides of the gears fit tightly against the housing. Material from the extruder enters between the two gears at the suction inlet, fills this space, moves along the housing as the teeth rotate, and is finally discharged when the teeth mesh.

GL pump structural features

1) Simple structure, low price; 2) Low operational requirements, wide application; 3) The end covers and the spaces between the gear teeth form many fixed sealed working chambers, so it can only be used as a positive displacement pump. The gears adopt a new technology at the advanced international level of the nineteen-nineties -- double-arc sine curve tooth profile arc. Compared with involute gears, its most prominent advantage is that there is no relative sliding on the tooth flank surface during the gear meshing process, so there is no wear on the tooth flanks, 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 as 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 separately 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 according to specific usage conditions and user requirements.

GL pump working principle

The concept of a gear pump is very simple. Its most basic form consists of two gears of identical size meshing and rotating within a closely fitted housing. The interior of this housing resembles the figure "8", with the two gears installed inside; the outer diameter and sides of the gears fit tightly against the housing. Material from the extruder enters between the two gears at the suction inlet, fills this space, moves along the housing as the teeth rotate, and is finally discharged when the teeth mesh. A gear pump is also called a positive displacement device, similar to a piston in a cylinder. When one tooth enters the fluid space of another tooth, because the liquid is incompressible, the liquid and the tooth cannot occupy the same space at the same time, so the liquid is mechanically squeezed out. Due to the continuous meshing of the teeth, this phenomenon occurs continuously, thus providing a continuous discharge volume at the pump outlet. With each revolution of the pump, the discharged volume is the same. As the drive shaft rotates continuously, the pump discharges fluid continuously. The pump flow rate is directly related to the pump speed. In reality, there is a very small amount of fluid loss within the pump, because this fluid is used to lubricate the bearings and both sides of the gears, and the pump body cannot possibly have a gap-free fit, so it cannot discharge 100% of the fluid from the outlet. Therefore, a small amount of fluid loss is inevitable, which prevents the pump's operating efficiency from reaching 100%. However, the pump can still operate well, and for most extruded materials, it can still achieve an efficiency of 93% to 98%. For fluids whose viscosity or density changes during the process, this pump is not significantly affected. If there is a damper, such as a filter screen or a restrictor placed on the discharge side, the pump will push the fluid through them. If this damper changes during operation, i.e., if the filter screen becomes dirty or clogged, or if the back pressure of the restrictor increases, the pump will still maintain a constant flow rate until it reaches the mechanical limit of the weakest component in the device (usually a torque limiter is installed). The speed of a pump is actually limited, mainly depending on the process fluid. If oil is being transported, the pump can rotate at high speeds, but when the fluid is a high-viscosity polymer melt, this limitation increases significantly. It is very important to fill the space between the two teeth on the suction inlet side with high-viscosity fluid. If this space is not fully filled, the pump cannot discharge an accurate flow rate, so the PV value (pressure × flow velocity) is another limiting factor and a process variable. Due to these limitations, gear pump manufacturers will provide a series of products, i.e., different specifications and displacements (volume discharged per revolution). These pumps will be matched with specific application processes to optimize system capacity and price.

GL pump troubleshooting

1) Fault phenomenon: Pump fails to 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 at low-speed operation; 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 noise. Fault causes: a, large coupling eccentricity or poor lubrication; b, motor fault; 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 shaft seal assembly; d, shaft or bearing wear; e, motor fault. 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 causing 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 specializes in selling German GL liquid pumps, GL gear pumps, GL diaphragm pumps, GL centrifugal pumps, GL plunger pumps, GL vacuum pumps, GL screw pumps, GL submersible pumps, GL peristaltic pumps, GL lubrication pumps, GL vane pumps, GL metering pumps, GL hand pumps, GL drum pumps, GL lobe pumps, GL booster pumps, GL liquid pumps, GL air pumps. Original German imports. Welcome customers to inquire and order.