DE2700226A1 - Rotating piston pump with stub shafts - has baffles at piston ends deflecting condensate into centrifugal ejection grooves - Google Patents

Abstract

The pump has two rotating pistons in a housing and these pistons do not contact each other. The pistons are held by end shaft stubs in bearing plates and they are in contact with lubricant filled housing parts. The end of a piston (2) has a sleeve (15) with sealing rings (14). On this sleeve slides a baffle sleeve (16) with a conical end, the latter deflecting condensate away from sealing rings. The condensate runs down the inner surface of the bearing plate into conical groove (19) at the piston end. The condensate and other liquids have to be kept away to ensure reliable operation of the pump at high operating speed.

Description

Roots pumps

The invention relates to rotary piston vacuum pumps and rotary piston compressors, also known as Roots pumps or blowers, in the housing of which are inevitably controlled roll two pistons against each other without touching the housing or each other to have.

The pistons of such pumps are in the end shields on both sides stored in roller bearings. A shaft journal of a piston protrudes on one side About the end shield for receiving a drive coupling or drive pulley the other side protrudes two shaft journals of the pistons to accommodate the synchronism ensuring gears over the end shield. Both sides are still Cover provided that form the bearing or gear housing. These housings are up filled to a certain extent with lubricants, which in a suitable manner - e.g.

by centrifugal disks - be fed to the bearings or gears. Because of the high speed of such machines and the associated load The lubricant, it is important that this is done before the admixture of foreign matter To be protected against the ingress of foreign matter from the pump chamber into the gear unit and to prevent the bearing housing from being in the end shields between the roller bearings shaft seals are attached to the passage into the pump chamber. Bring this with the disadvantage that they wear out very quickly and have a high technical level Require effort. One has therefore switched to using the shaft feedthroughs Equip labyrinth seals, e.g. piston ring seals. These have have a repellent effect, but are not absolutely tight. Especially when ventilating of the pumps there are pressure differences between the two sides of these seals, who strive to become balance, with liquids being carried away can be.

The invention has set itself the task of accumulating in the pump chamber Keep condensates or any other penetrating liquids away from the ducts.

This object is achieved according to the invention in that around the shaft journal grooves are pierced around in the side surface of the piston, their outer boundary surfaces towards the end shield are conical and that guides are provided, the liquids that run down on the inner surfaces of the end shields are conical Feed grooves so that they are thrown outwards by centrifugal force and at another point drain down to the outlet port of the pump.

The invention is illustrated by two exemplary embodiments with reference to the drawings described in more detail: Fig.l shows a horizontal section through a Roots piston pump - the direction of view is the direction of flow.

2 shows a section through a bearing point in which the seal is in the end shield.

Fig.3 shows a bearing point in which the seal in a Groove of the piston was preferred.

Fig. 1: The two pistons 2 and 3 move in the housing 1.

Your shaft journals 4 and 5 are on one side in the bearing plate 6 stored; they carry gears 7 and 8.

The oil-filled gear housing is formed by the cover 9.

The pin 4 penetrates the cover 9 to accommodate the drive coupling. On the other hand, the shaft journals t0 and 11 are carried by the bearing plate 12. The oil supply for the bearings is held in the cap 13.

Fig.2 shows part of the piston 2, the shaft journal 4 and the Wall of the end shield 6. The piston rings 14 sit in a bush 15 and seal against the bore of the end shield 6. The deflector bushing 16 protrudes into the annular groove 17 of the piston 2 and is provided with a deflecting edge 18. Through this and an annular chamber is formed by the conical outer wall 19 of the annular groove 17, in which the condensate running down the wall of the end shield 6 collect can without it having the opportunity to get to the piston rings 14. if the pistons rotate, the condensate is moved by the centrifugal force over the slope of the Groove forced outwards and cannot do so, even with a large amount of condensate reach the sealing rings and must drain down to the outlet of the pump.

In Fig. 3, the shaft journal has the designation 20. The only partially The piston 21 shown has a relatively deep recess 22 in which carried by a bush 24 firmly connected to the wall 23 of the end shield Piston rings 25 are guided to the outside exciting. The socket 24 is designed so that it forms with the wall 23 a channel 26 in which condensate can collect. Between the seat of the piston rings 25 and the side surface of the piston has the turning in the piston 21 a conical widening 27 to the outside, which ensures, that when the piston is turned, any condensate that may penetrate is thrown outwards will.

Claims (1)

Patent claim Roots pump with two in one housing without contact rotating pistons, which are stored with shaft journals in end shields and in lubricant filled housing are continued, characterized in that around the shaft journal grooves are pierced around in the side surfaces of the piston, their outer boundary surface widening towards the end shield, are conical and that guides are provided, the liquids running down on the inner surfaces of the end shields are conical Feed grooves.