WO2001013028A1

WO2001013028A1 - Arrangement in connection with centralized grease lubrication system

Info

Publication number: WO2001013028A1
Application number: PCT/FI2000/000688
Authority: WO
Inventors: Rauno Vehmaa
Original assignee: Safematic Oy
Priority date: 1999-08-12
Filing date: 2000-08-11
Publication date: 2001-02-22
Also published as: FI19991714A; AU6573300A; FI108077B

Abstract

The invention relates to an arrangement in connection with a centralized grease lubrication system, the arrangement comprising a grease container (8), pump unit, control centre, pipes, grease feeders and pressure switches, in which case grease is arranged to be pumped from the grease container (8) along the pipes to the grease feeders and further to the lubrication points, the pump unit being mounted in the grease container (8) so that its location changes as the surface of grease falls in the grease container (8). To enable use of a grease container with a small volume, the pump unit comprises at least one piston pump (7) and a follower plate (13) mounted at the bottom of the unit, the plate being arranged to press against the inner wall of the grease container (8) and scrape off the grease stuck to the wall, and a power source (9) which is placed on top of the grease container, connected to a piston pump (7) provided at the bottom of the pump unit by means of a shaft member (10) and arranged to drive the piston pump, and a scraping plate structure (11) which is mounted below the piston pump (7) and functions like a screw by means of the shaft member (10), the structure being arranged to feed grease into the piston pumps (7) in the pump unit as it rotates and to simultaneously pull the pump unit connected to the follower plate (13) down towards the bottom of the grease container (8).

Description

ARRANGEMENT IN CONNECTION WITH CENTRALIZED GREASE LUBRICATION SYSTEM

The invention relates to an arrangement in connection with a centralized grease lubrication system, the arrangement comprising a grease con- tainer, pump unit, control centre, pipes, grease feeders and pressure switches, in which case grease is arranged to be pumped from the grease container along the pipes to the grease feeders and further to the lubrication points, the pump unit being mounted inside the grease container so that its location changes as the surface of grease falls in the grease container. Centralized grease lubrication systems known in the field typically consist of an electric control centre, pump centre, manifolds, grease feeders and pressure switches. The pump centre comprises a grease container and a pump unit by means of which grease is pumped from the container to the lubrication points. Industrial lubrication systems typically employ pneumatic pump centres, and the size of the grease container is usually 50 litres and 200 litres. The consistency (penetration value) of the grease used as the lubricant is usually in NLGI class 0 to 2.

When the grease consistency is in NLGI class 2, the fluidity of grease is limited, which often causes problem to the pumpability, for example. The thickness of grease also causes pumping problems in the grease container itself because the inlet at the bottom of the barrel used as the grease container cannot take in enough new grease during pumping. One has attempted to solve this problem in prior art solutions by placing different plates on the surface of the grease in the grease container which press the grease downwards as the amount of grease decreases in the container.

The above-mentioned solution has been improved by using a structure in which a pump is arranged on the surface of the plates, in which case the weight of the pump facilitates the suction of the pump.

The solutions described above have provided practical construc- tions for solutions utilizing large grease containers of 50 and 200 litres. However, these solutions are impractical in constructions employing small barrels of 20 litres. One reason for this is that when grease sticks to the wall of a barrel with small dimensions used as the grease container, only small overpressure is generated at the bottom of the barrel. It should be reminded here that a bar- rel of 20 litres is a rather shallow element. The object of the invention is to provide an arrangement which eliminates the problems related to the prior art solutions, i.e. to provide a solution which is also suitable for use in small grease containers, such as barrels of 20 litres. This is achieved with the arrangement of the invention. The arrange- ment according to the invention is characterized in that the pump unit comprises at least one piston pump and a follower plate mounted at the bottom of the unit, the follower plate being arranged to press against the inner wall of the grease container and scrape off the grease stuck to the wall, and a power source which is placed on top of the grease container and connected to the piston pump mounted at the bottom of the pump unit by means of a shaft member and arranged to drive the piston pump, and a scraping plate structure which is mounted below the piston pump and functions like a screw by means of the shaft member, the structure being arranged to feed grease into the piston pumps in the pump unit as it rotates and to simultaneously pull the pump unit connected to the follower plate down towards the bottom of the grease container.

The main advantage of the invention its versatility, i.e. the arrangement according to the invention enables a solution which can be mounted on top of a standard grease container of 20 litres and is suitable for pumping grease of NLGI class 2. A further advantage of the invention is that it can also be used in large grease containers, i.e. barrels of 200 and 50 litres. In addition, the invention is simple and thus inexpensive to install and use. The invention can also be applied in prior art devices in an advantageous manner.

In the following, the invention will be described more closely by means of a preferred embodiment illustrated in the accompanying drawing, in which

Figure 1 is a schematic perspective view of a typical centralized grease lubrication system according to the prior art, and

Figure 2 is a schematic side view of an arrangement according to the invention.

Figure 1 is a schematic view of a typical centralized grease lubrication system according to the prior art. The system typically comprises an electric control centre 1 and a pump centre 2, and further manifolds 3, pressure switches 4 and grease feeders 5. The pump centre 2 comprises a barrel 6 used as the grease container, which is e.g. a barrel of 200 litres in this example. The structure and function of the lubrication system shown in Figure

1 are fully known to a person skilled in the art, for which reason these will not be discussed in greater detail here. In general, the idea is that the pump centre

2 pumps grease from the barrel 6 via the manifolds 3 and the grease feeder 5 to the lubrication points, e.g. to bearings as shown in Figure 1. The system of

Figure 1 has all the disadvantages described above.

To enable the use of a standard-sized grease container of 20 litres, an arrangement shown schematically in Figure 2 is used as the grease container according to the basic idea of the invention. As illustrated in Figure 2, the pump unit used in the arrangement of the invention comprises at least one piston pump 7 and one follower plate 13 mounted at the bottom of the unit. The follower plate is arranged to press against the inner wall of the grease container 8 and scrape off the grease stuck to the wall. Further, a power source 9 is placed on the top of the grease container 8. In the example of Figure 2 the grease container 8 is the above-mentioned standard-sized barrel of 20 litres. There are two piston pumps 7 in the example of Figure 2. The number of the pumps may vary according to the need. The power source 9, which is an electric motor in the example of Figure 2, is connected to a piston pump 7 at the bottom of the pump unit with a shaft member 10 and arranged to drive the pis- ton pump 7. A scraping plate structure 11 , which functions like a screw by means of the shaft member 10, is mounted below the piston pump 7. The follower plate 13 forces grease to move downwards into the space where the grease is in the grease container 8, from which the scraping plate structure 11 feeds it into the piston pumps as it rotates. At the same time, the scraping plate structure 11 pulls the pump unit connected to the follower plate 13 down towards the bottom of the grease container 8.

As can be seen in Figure 2, the arrangement of the invention comprises a an electric pump unit which is mounted on top of a standard-sized barrel 8 of 20 litres and the bottom of which is provided with piston pumps 7 and a scraping plate structure 11 , which feeds grease into the piston pumps as it rotates like a screw and at the same time in a way pulls the pump unit closer towards the bottom of the grease container. Movement of grease in the grease section of the grease container is illustrated schematically with arrows. The pump unit falls in the grease container as the amount of grease decreases in the container. As the scraping plate structure 11 rotates, it intensifies this movement. The pump unit can be placed on top of the grease container 8 by means of a suitable cover structure 15, as illustrated in the figure.

The shaft member 10, which rotates the scraping plate structure 11 , is also arranged to drive the piston pumps 7 as it rotates. For this purpose the shaft member is provided with a cam member 12 which moves the piston of the piston pump 7. The piston can be made to move in the opposite direction e.g. by means of a spring member as shown in the example of Figure 2. The piston pumps 7 pump the grease out of the grease container 8 via pipe fittings 14. Figure 2 illustrates only one pipe fitting 14. The embodiments described above are not intended to limit the invention in any way, but the invention can be modified completely freely within the scope of the claims. Thus the arrangement of the invention or its details do not necessarily need to be exactly the same as those illustrated in the figure, but other solutions are also possible. As stated above, the invention is not lim- ited to a barrel of 20 litres, but the invention can also be applied to barrels of other sizes, etc.

Claims

1. An arrangement in connection with a centralized grease lubrication system, the arrangement comprising a grease container (8), pump unit, control centre, pipes, grease feeders and pressure switches, in which case grease is arranged to be pumped from the grease container (8) along the pipes to the grease feeders and further to the lubrication points, the pump unit being mounted in the grease container (8) so that its location changes as the surface of grease falls in the grease container (8), and the pump unit comprising at least one piston pump (7) and a follower plate (13) mounted at the bottom of the unit, the plate being arranged to press against the inner wall of the grease container (8) and scrape off the grease stuck to the wall, and a power source (9) which is placed on top of the grease container, connected to a piston pump (7) provided at the bottom of the pump unit by means of a shaft member (10) and arranged to drive the piston pump, characterized in that the ar- rangement comprises a scraping plate structure (11) which is mounted below the piston pump (7) and functions like a screw by means of the shaft member (10), the structure being arranged to feed grease into the piston pumps (7) in the pump unit as it rotates and to simultaneously pull the pump unit connected to the follower plate (13) down towards the bottom of the grease container (8).

2. An arrangement according to claim 1, characterized in that the lower end of the shaft member (10) is provided with a cam member (12) arranged to move the piston of the piston pump (7) as the shaft member rotates (10) to provide the pumping action.

3. An arrangement according to claim 1 or 2, characterized in that the grease container (8) is a standard-sized barrel of 20 litres.

4. An arrangement according to any one of claims 1 to 3, c h a r - acterized in that the power source (9) is an electric motor.