German KRACHT pump KRACHT model KRACHT price

KRACHT pumps are rotary pumps that rely on the change and movement of the working volume formed between the pump cylinder and meshing gears to transport liquids or increase their pressure. 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, forcing the liquid into the pipeline. The suction chamber and discharge chamber are separated by the meshing line of the two gears. The pressure at the discharge port of a gear pump depends entirely on the resistance at the pump outlet.

KRACHT pump structural features

1) Simple structure and low cost; 2) Low operational requirements and 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 the double circular arc sine curve tooth profile, an advanced technology from the nineteen-nineties. Compared with involute gears, its most prominent advantage is that there is no relative sliding on the tooth flank during meshing, resulting in no wear on the tooth surface, smooth operation, no fluid trapping, low noise, long service life and high efficiency. This pump breaks away 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 the pump is designed in two forms: one is mechanical seal and the other is packing seal, which can be determined according to specific operating conditions and user requirements.

KRACHT pump working principle

The concept of a gear pump is very simple. Its most basic form consists of two gears of the same size meshing and rotating within a closely fitted housing. The interior of this housing resembles an "8" shape, with the two gears installed inside. The outer diameter of the gears and both sides fit closely with the housing. Material from the extruder enters between the two gears at the suction inlet and fills this space. As the teeth rotate, the material moves along the housing and is finally discharged when the two teeth mesh. Gear pumps are also called positive displacement devices. Like 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. Thus, the liquid is mechanically squeezed out. Due to the continuous meshing of the teeth, this phenomenon occurs continuously, providing a continuous discharge volume at the pump outlet. The discharged volume is the same for each revolution of the pump. As the drive shaft rotates continuously, the pump discharges fluid continuously. The flow rate of the pump is directly related to the pump speed. In reality, there is a small amount of fluid loss within the pump because this fluid is used to lubricate the bearings and both sides of the gears. Furthermore, the pump body cannot have a gap-free fit, so it is impossible for the fluid to be discharged from the outlet 100%. 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 achieve an efficiency of 93% to 98%. This type of pump is not significantly affected by fluids whose viscosity or density changes during the process. 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 becomes dirty or clogged, or if the back pressure of the restrictor increases—the pump will still maintain a constant flow rate until the mechanical limit of the weakest component in the device is reached (a torque limiter is usually installed). There is actually a limit to the speed of a pump, which mainly depends on the process fluid. If oil is being transported, the pump can rotate at high speeds, but this limit increases significantly when the fluid is a high-viscosity polymer melt. 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. Therefore, the PV value (pressure × flow velocity) is another limiting factor and a process variable. Due to these limitations, gear pump manufacturers offer a series of products with different specifications and displacements (volume discharged per revolution). These pumps are matched to specific application processes to optimize system capacity and price.

KRACHT pump troubleshooting

1) Fault phenomenon: Pump fails to discharge material. Cause of fault: 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. Countermeasure: a, confirm rotation direction; b, confirm whether valves are closed; c, check valves and pressure gauge; d, check liquid viscosity. Check if flow appears proportional to speed when running at low speed; if there is flow, the inflow is insufficient. 2) Fault phenomenon: Insufficient pump flow. Cause of fault: a, suction or discharge valve closed; b, low inlet pressure; c, blocked outlet pipeline; d, packing box leakage; e, speed too low. Countermeasure: a, confirm whether valves are closed; b, check whether valves are open; c, confirm whether discharge volume is normal; d, tighten. If heavy leakage affects production, stop operation and dismantle for inspection; e, check the actual speed of the pump shaft. 3) Fault phenomenon: Abnormal noise. Cause of fault: a, large coupling eccentricity or poor lubrication; b, motor failure; c, gearbox abnormality; d, improper installation of shaft seal; e, shaft deformation or wear. Countermeasure: 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. Cause of fault: a, excessive outlet pressure; b, melt viscosity too high; c, improper assembly of shaft seal; d, shaft or bearing wear; e, motor failure. Countermeasure: a, check downstream equipment and pipelines; b, test viscosity; c, check shaft seal and adjust appropriately; d, stop and check; manually turn the shaft to see if it is too heavy; e, check motor. 5) Fault phenomenon: Pump stops suddenly. Cause of fault: a, power outage; b, motor overload protection; c, coupling damage; d, excessive outlet pressure, interlock response; e, abnormal biting inside the pump; f, shaft and bearing adhesion/seizure. Countermeasure: a, check power supply; b, check motor; c, open safety cover and check by turning shaft; d, check instrument interlock system; e, after stopping, confirm by turning shaft forward and reverse; f, confirm by turning shaft. 6) Fault phenomenon: Seal oil leakage. Cause: a, shaft seal not adjusted properly; b, sealing ring worn causing large clearance; c, dynamic and static ring friction surfaces of mechanical seal damaged; d, spring relaxation. Countermeasure: 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 KRACHT gear pumps, KRACHT gear pumps, KRACHT diaphragm pumps, KRACHT centrifugal pumps, KRACHT piston pumps, KRACHT vacuum pumps, KRACHT screw pumps, KRACHT submersible pumps, KRACHT peristaltic pumps, KRACHT lubrication pumps, KRACHT vane pumps, KRACHT metering pumps, KRACHT hand pumps, KRACHT drum pumps, KRACHT lobe pumps, KRACHT booster pumps, KRACHT liquid pumps, KRACHT air pumps. Original imports from Germany. Welcome customers to inquire and order.