Despite better precautions, geared slant-shaft variable piston pumps usually succumb to the wear of gears, sleeves and bearings over time. As the gap increases, the efficiency gradually decreases and the flow slip increases: the pumped fluid leaks from the discharge port back to the suction side. The flow slip is proportional to the cube of the gap between the gear teeth and the housing, so in practice, wear has a small effect until a critical point is reached, and performance decreases rapidly from that critical point.
The gear pump continues to pump under back pressure, and if it is blocked downstream, it will continue to pressurize the system until the pump, pipeline or other equipment fails. Although most gear pumps are equipped with a safety valve for this reason, it has been recommended to install safety valves elsewhere in the system to protect downstream equipment. Internal speed gear pumps running at low speeds are usually preferred for cutting sensitive liquids such as food, paint and soap. The high speed and low clearance of external gear designs make them unsuitable for these applications. When hygiene is important, internal gear pumps are also an option because they are mechanically simple and easy to disassemble, clean and reassemble.
What is the main application of the inclined axis variable piston pump? This pump is usually used to pump high viscosity fluids such as oil, paint, resin or food. They are both preferred in applications requiring dosing or high pressure output. Pump output is not greatly affected by pressure, so they also tend to be preferred in situations of irregular supply.