Pump elements for progressive pumps
Central lubrication systems are able to supply a large number of lubrication points with a defined amount of lubricant at the same time. Single-line and progressive systems essentially consist of a pump unit, one or more metering devices for metering the lubricant, and the main and secondary lines required to transport the lubricant. The heart of the system is the pump unit, which is responsible for the pressure build-up in the system. The unit sucks in lubricant from a reservoir provided for this purpose and pumps it through the main line to the metering device. The pump element plays an important role in this process.
Up to three pump elements can be installed in each KFG piston pump unit. The progressive pump elements are responsible for ensuring that the lubricant is transported to the lubrication points or the metering devices. The principle of operation is based on a piston which pushes lubricant out of the pump housing through forward movements and sucks in new lubricant when moving backward.
Technical details on pump elements
Progressive pump elements such as the KFG1.U1 can be installed at various points on the pump housing. When pumping, the shaft of the unit connected to the motor drives an eccentric. This eccentric converts the rotary movement of the shaft into a longitudinal movement of the pump element and thus ensures that the element moves up and down.
Lubricant is pressed out of the housing during the forward movement and is sucked in more during the backward movement. The element is reset either using a spring return or a forced return. The progressive pump elements with spring return are suitable for most purposes and are based on an automatic return of the element. For particularly demanding tasks with extremely low temperatures or very high viscosities, a forced return is usually used.
Depending on the application, between one and three pump elements are installed on the piston pump unit. Possible mounting positions are on the unit on the left, right and front side. The lubricant is transferred to the line via an M14x1.5 internal thread. If more than one progressive pump element is used, the lines outside the pump housing are brought together again. The volume flows of the individual elements are thus added up to a total value in the main line.
Pump elements from SKF
For the KFG piston pump unit, SKF offers various pump elements with different volume flows. The spring-returned pump elements can be identified using the marking grooves on the head. The element with four grooves is suitable for a volume flow of 0.8 cm³ of lubricant per minute, while the model KFG1.U1 has one groove and delivers 2.5 cm³ of lubricant per minute. At the upper end of the spectrum is the element of type KFG1.U0 with a volume flow of 5.0 cm³. It should be noted that the stated quantity refers to greases of NLGI class 2 at a temperature of 20°C and a counter pressure of 50 bar.
If fewer than three progressive pump elements are used on the housing, the corresponding outputs are closed with screws.