GB2043951A

GB2043951A - Device for Damping Oscillations In Pressure Fluid

Info

Publication number: GB2043951A
Application number: GB7900819A
Authority: GB
Original assignee: Hayden Nilos Conflow Ltd
Current assignee: Hayden Nilos Conflow Ltd
Priority date: 1979-01-09
Filing date: 1979-01-09
Publication date: 1980-10-08

Abstract

The device has at least one disc 4A, 4B having a periphery affording a close fit within a counterbore in a body 1 and a spiral groove 5A, 5B in at least one face, at least one disc 8 having a periphery affording a close fit within the counterbore and a flat face abutting the grooved face of the grooved disc, the discs each having a hole 7A, 7B, 10 communicating with the inner and outer ends respectively of the spiral groove to provide a restricted flow path through the device. Alternatively, a disc having spiral grooves in each face is sandwiched between a pair of plain discs (Fig. 3). Filters 15A, 15B are provided. <IMAGE>

Description

SPECIFICATION Vibration Damping Devices for Use in Pressure Systems This invention relates to vibration damping devices for use in pressure systems. A common occurrence of such vibrations is in a pressure gauge where the needle tends to vibrate violently under certain pressure and other physical conditions, so that a definite pressure reading cannot be ascertained.

The object of the invention is to provide a vibration damping device of simple robust construction readily capable of being varied to suit the amount of damping required.

According to the present invention, a vibration damping device comprises a body with a bore and a counterbore, at least one disc having a periphery affording a close fit within the counterbore in the body and a spiral groove in at least one face, at least one disc having a periphery affording a close fit within the counterbore in the body and a flat face abutting the grooved face of the grooved disc, and a closure for the counterbore with a bore through the closure, the discs each having a hole through from one face to the other communicating with the inner and outer ends respectively of the spiral groove and also with the bores in the body and closure respectively, and the body and closure also having coupling parts coaxial with their respective bores.

With the device connected in a pressure system by means of the coupling parts of the body and closure, the bores become respectively an inlet and an outlet of the device, and pressure fluid is communicated between them by passing through one of the holes in the discs, round the spiral groove, and through the hole in the other disc, the appreciable length of restricted passage afforded by the spiral groove being effective to damp out vibrations within a minor proportion of the length of the device.

Conveniently, two spiral grooved faces are provided, either on both faces of one disc sandwiched between two flat-faced discs or on two discs sandwiching a disc with both faces flat, so that a hole in one disc can be coaxial with an inlet bore and a hole in another disc can be coaxial with an outlet bore, and the outer ends of the spiral grooves being connected by a hole in the disc sandwiched between the discs with the coaxial holes. The provision of two spiral grooved faces doubles the length of the restricted passage and so further increases the effectiveness to damp out vibrations without materially adding to the length of the device. Three, four or more spiral grooved faces may be provided by adding an appropriate number of grooved and flat-faced discs.

A filter is preferably provided between an inlet bore and the assembly of discs, so as to prevent dirt in the pressure fluid clogging up the spiral groove or grooves, and conveniently a filter is provided between each bore and the assembly of discs, so that the device may be used either way round, i.e., with either bore serving as the inlet bore.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:- Figure 1 is a longitudinai section through a vibration damping device in accordance with the invention; Figure 2 is an elevation of the grooved face of one of the grooved discs of the device of Figure 1; and Figure 3 corresponds to part of Figure 1 showing the assembly of grooved and flat-faced discs having an alternative formation.

In Figure 1 a vibration damping device comprises a body 1 with a bore 2 and a counterbore 3; a pair of discs 4A, 4B, each having a periphery affording a close fit within the counterbore 3, a spiral groove 5A or 5B (see also Figures 2 and 3) in one face 6A or 6B, and an axial bore 7A or 7B; a disc 8 having a periphery affording a close fit within the counterbore 3, a pair of flat faces 9A, 9B abutting the grooved faces 6A, 6B respectively of the discs 4A, 4B, and a hole 10 adjacent its periphery communicating with the outer ends of the spiral grooves 5A, 5B; and a closure 11 for the counterbore 3 with a bore 12 through the closure; the body 1 and closure 11 also having male and female screwthreaded coupling parts 13, 14 respectively.

Filters 1 so, 1 SB are provided between the bores 2, 1 2 respectively and the assembly of discs 4A, 4B, 8. The closure 11 is secured in the body 1 by mating screw-threads 16, 1 7 and sealed therein by an O-ring 18, and a bored spacer 1 9 between the filter 1 SA and the assembly of discs 4A, 4B, 8 is also sealed in the body by an O-ring 20. Sealing washers 21 are provided on each side of the filter 1 5B and between the spacer 1 9 and the assembly of discs 4A, 4B, 8. An O-ring 22 is also provided in the female coupling part 14.

Assuming the device to be connected in a pressure system by means of the coupling parts 13, 14 with the bore 2 as an inlet and the bore 12 as an outlet, e.g., to a pressure gauge, pressure fluid is communicated between them through the filter 1 SA and bored spacer 1 9 to the hole 7A in the disc 4A, round the spiral groove 5A, through the hole 10 in the disc 8, round the spiral groove 5B in the disc 4B, through the hole 7B and through the filter 1 SB.

It will be evident that the spiral grooves 5A, 5B together form a restricted passage of very appreciable length within a minor proportion of the length of the device, and it is this long restricted passage that damps out vibrations in the pressure system.

In Figure 3 the faces 6A, 6B of the discs 4A, 4B are flat and the grooves 5A, 5B are provided in the faces 9A, 9B of the disc 8, but the effect is no different to that of the formation in Figure 1.

Other arrangements or formations of grooved and flat-faced discs are feasible, e.g., to afford an even longer restricted passage, without departing from the scope of the invention.

Claims

1. A vibration damping device comprising a body with a bore and a counterbore, at least one disc having a periphery affording a close fit within the counterbore in the body and a spiral groove in at least one face, at least one disc having a periphery affording a close fit within the counterbore in the body and a flat face abutting the grooved face of the grooved disc, and a closure for the counterbore with a bore through the closure, the discs each having a hole through from one face to the other communicating with the inner and outer ends respectively of the spiral groove and also with the bores in the body and closure respectively, and the body and closure also having coupling parts coaxial with their respective bores.

2. A device as in Claim 1, wherein two spiral grooved faces are provided, either on both faces of one disc sandwiched between two flat-faced discs or on two discs sandwiching a disc with both faces flat, with a hole in one disc coaxial with an inlet bore and a hole in another disc coaxial with an outlet bore, and the outer ends of the spiral grooves being connected by a hole in the disc sandwiched between the discs with the coaxial holes.

3. A device as in Claim 1 or Claim 2, wherein a filter is provided between an inlet bore and the assembly of discs, so as to prevent dirt in the pressure fluid clogging up the spiral groove or grooves.

4. A device as in any one of Claim 1 to 3, wherein a filter is provided between each bore and the assembly of discs, so that the device may be used either way round.

5. A vibration damping device substantially as hereinbefore described with reference to the accompanying drawings.