WO2008028235A1

WO2008028235A1 - Gland packer

Info

Publication number: WO2008028235A1
Application number: PCT/AU2007/001308
Authority: WO
Inventors: John Wentworth Bucknell; Robert Wentworth Bucknell
Original assignee: Technofast Industries Pty Ltd
Priority date: 2006-09-05
Filing date: 2007-09-05
Publication date: 2008-03-13

Abstract

A gland packer (10) is provided to apply a load to a gland packing (P) between the housing (H) and shaft (S) of a machine (M), where the packer body (20) and pressure ring or plate (30) are interconnected by a plurality of ram assemblies (30) connected to a source of pressurised fluid (PF), controlled by a valve (V).

Description

TITLE: GLAND PACKER

BACKGROUND OF THE INVENTION

1. Field of the Invention

THIS INVENTION relates to a gland packer. The invention particularly relates, but is not limited to, a hydraulic gland packer operable to apply the load to the gland packing of a machine, such as a pump or motor.

2. Prior Art

Gland packing seals are commonly used to seal a rotating shaft to the housing of a machine (eg., a pump or motor) in which the rotating shaft is joumalled by suitable bearings or bushes.

The gland packings are designed to prevent the escape of liquids from the interior to the exterior of the housing.

In many applications, the liquids, eg., being pumped by the machines, are dangerous and/or toxic to humans and the environment generally. Examples include mining slurries; caustic liquids such as sodium hydroxide (caustic soda); and acids such as sulfuric acid, nitric acid and hydrochloric acid.

The gland packings are provided with gland packers which are mounted on the machine and designed to provide a loading force on the gland packings to maintain the gland packings in sealing contact with the machine housings and the rotating shafts. As the gland packings wear or deteriorate (eg., under the effects of the liquids in the machines), leaks can occur and the gland packers must be adjusted to increase the applied load (or return the load to the original setting) to re-seal the gland packings to the machine housings and/or the rotating shaft to stop the leaks.

Usually, the gland packers must be adjusted while the machines remain operating; and usually the maintenance operator must make adjustments on opposite sides of the gland packers while the liquids leak from the machine until the required load is applied to the gland packings. In many cases, access to the gland packers is limited and the maintenance operator may need to reach over (or under) the rotating shafts to access the distal side of the gland packers to adjust them. SUMMARY OF THE PRESENT INVENTION

It is an object of the present invention to provide a hydraulic gland packer which can apply a load to a gland packing in a machine.

It is a preferred object of the present invention to provide such a gland packer where the load can be varied from a location spaced, or remote from, the machine.

It is a further preferred object to provide such a gland packer which enables remote monitoring of the load on the gland so that the load can be increased before it falls below a pre-set level.

It is a still further preferred object of the present invention to provide a gland packer where the degree of wear on the gland packing can be monitored, to enable removal and replacement before failure of the gland packing.

It is a still further preferred object of the present invention to provide such a gland packer which can be supplied as original equipment manufacture (O.E.M.) or can be "retro-fitted" to replace existing (mechanical) gland packers.

It is a still further preferred object of the present invention to provide such a gland packer which is relatively easy to install and operate. Other preferred objects of the present invention will become apparent from the following description.

In one aspect, the present invention resides in a gland packer for a gland packing fitted to a housing of a machine, the gland packer including: a packer body mountable on the housing of the machine; a pressure ring or plate slidably mounted on the packer body and engageable with the gland packing; and at least one ram assembly interposed between the pressure ring or plate and the packer body, connectable to a source of pressurised fluid, and operable to move the pressure ring or plate relative to the packer body to apply a load to the gland packing.

Preferably, the packer body is substantially annular, with a substantially central bore therethrough, to receive a rotating shaft journalled in the housing and to be sealed thereto by the gland packing, and the housing has lugs or other mounting means to enable the packer body to be mounted on studs, bolts, spigots or the like, extending from the housing of the machine.

Preferably, nuts or other fasteners on the studs or the like enable the gland packer to be mounted on the housing so that the pressure ring or plate applies a static pre-load to the gland packing.

Preferably, the packer body has a plurality of cylinders of respective ram assemblies provided at (preferably) equal radial spacings; and fluid passage(s) connect the cylinders to at least one inlet port to enable the pressurised fluid to cause the ram assemblies to move the pressure ring or plate to apply a load to the gland packing.

However, the packer body and pressure ring or plate may be interconnected by a single annular ram assembly, where an annular piston, eg., connected to, or formed integrally with, the pressure ring or plate is received in an annular cylinder connected to, or integral with, the packer body; or vice versa.

The or each ram assembly preferably has a respective piston, slidably received in (and sealed to) a respective cylinder, where each piston is connected to, or engages a face on, the pressure ring or plate. Preferably, the source of pressurised fluid has at least one valve to control the flow of pressurised fluid to the gland packer; and preferably at least one gauge means to enable the pressure of the pressurised fluid to be monitored.

For original equipment manufacture (O. E. M.) installations, preferably the packer body and the pressure ring or plate, are each provided as unitary components; while for "retro-fit" installations, preferably, the packer body and the pressure ring or plate are each provided in two halves which can be secured together.

Preferably, the pressurised fluid is an oil or a grease. However, the fluid may be compressed air, where the gland packer is of a pneumatic, not hydraulic, configuration.

In a second aspect, the present invention resides in a method of applying a load to a gland packing mounted in the housing of a machine employing the gland packer hereinbefore described.

BRIEF DESCRIPTION OF THE DRAWINGS

To enable the invention to be fully understood, preferred embodiments will now be described with reference to the accompanying drawings, in which: FIG. 1 is an isometric view of a gland packer in accordance with the present invention with the pressure ring or plate in the retracted position;

FIG. 2 is a similar view showing the pressure ring in the fully extended position; FIG. 3 is a sectional side view corresponding to FIG. 1; and

FIG. 4 is a sectional side view corresponding to FIG. 2, showing the gland packer in use.

DETAILED DESCRIPTION OF THE

PREFERRED EMBODIMENTS The gland packer 10 has a packer body 20 and a pressure ring or plate 40 to be hereinafter described in more detail.

The embodiment illustrated in FIGS. 1 to 4 is designed for retro-fit installation to an existing machine M, such as a slurry or liquid- chemical pump. The machine M has a housing H in which is joumalled a rotatable shaft S (eg., a drive shaft connected to an electric motor), the shaft S being journalled in suitable bearings or bushes B in the housing of the pump and sealed thereto by a gland packing P. The particular configuration of the housing H/shaft S/gland packing P will depend on the manufacturer of the machine M and its intended applications.

The packer body 20 is split into "mirror-image" body halves 21 , 22 which are releasably secured together by respective clamping bolt/nut assemblies 23 which extend through aligned bores (not shown) in mounting lugs 24, 25 which are arranged to engage mounting studs or bolts S/B on the housing H of the machine and where nuts N can urge the pressure ring or plate 40 into a static pre-load with the gland packing P.

A plurality of ram assemblies 30 have their cylinders 31 provided at equally spaced locations within the packer body 20 and fluid passages 32 within the packer body 20 connect the cylinders 31 to a pair of fluid inlets 33; where the fluid inlets 33 are connected via a T-piece T to a remote source of pressurised fluid PF (eg., hydraulic oil or grease); where the flow of the pressurised fluid to the fluid inlets 33 is controlled by a valve V; and where the pressure of the fluid may be monitored by a pressure gauge G. The remote source of pressurised fluid PF may incorporate a pressure storage device, such as an accumulator, which may be kept above a preset pressure by a pump (not shown).

Each ram assembly 30 has a piston 34 slidably mounted in a respective cylinder 31 and sealed thereto by an O-ring seal 35. As shown in FIGS. 3 and 4, the distal ends of the rams 34 engage the pressure ring or plate 40, in a manner to be hereinafter described, to move the pressure ring or plate 40 from the fully retracted position shown in FIGS. 1 and 3 to the fully extended position shown in FIGS. 2 and 4. (NB: Preferably, the stroke of the pistons 34 relative to the cylinders 31 does not exceed 25mm, where the movement can be controlled by an over-stroke limit (not shown); and graduations or markings 49 may be provided on the pressure plate or ring 40 to indicate the degree of relative movement between the pressure plate or ring 40 and the packer body 20 to indicate the degree of wear on the gland packing P.) The pressure ring or plate 40 is split into ring halves 41 , 42 where each is of substantially L-section, where the "leg" forms an annular ring portion 43 slidably received within the packer body 20 and the "foot" forms a loading ring portion 44, where a distal face 45 engages the adjacent face of the packing ring P; and a proximal face 46 is engaged by the outer or "free" ends of the respective pistons 34.

In use, the packer body 20 and the pressure ring or plate 40 are separated into their respective halves; and a pressure body half 21/ pressure ring half 41 combination is applied to one side of the rotating shaft S and the other pressure body half 22/pressure ring half 42 is applied to the other side and the respective halves are brought together in alignment. The clamping bolt/nut assemblies 23 clamp the packer body halves 21 , 22 together; and the nuts N on the studs or bolts on the housing H of the machine M are tightened (as indicated by arrow SL) to cause the distal face 45 on the pressure ring or plate 40 to apply a static pre-load to the gland packing P. (During this stage, no pressurised fluid PF is applied to the gland packer 10 so that the pistons 34 are fully retracted in the cylinders 31.)

The valve V connecting the source of pressurised fluid PF to the gland packer 10 is opened to allow the pressurised fluid PF (eg., hydraulic oil or grease) to flow into the cylinders 31 and cause the pistons 34 to move towards their extended position to cause the pressure ring or plate

40 to apply a load to the gland packing P. The applied load will be proportionate to the pressure of the fluid, which can be monitored on the gauge G, and the flow is shut off when the gauge G reaches a pre-set pressure limit.

In use, the gland packing P will wear, and the pressure of the fluid in the cylinders 31 will cause the pressure ring or plate 40 to move towards the gland packing P (ie., away from the packer body 20) to continue to apply a load to the gland packing P. By monitoring the pressure of the fluid, the additional pressure may be applied thereto (via the valve V) to maintain the pressure of the fluid above a minimum pre-set limit to ensure the gland packing P does not leak.

When the pistons 34 are approaching their maximum useable stroke (or the graduations or markings 49 on the pressure ring or plate 40 indicate the pressure ring or plate 40 is approaching its maximum extension), the machine M may be shut down to enable replacement of the gland packing P before it undergoes leakage or catastrophic failure.

As the source of pressurised fluid PF, the valve V and the gauge G are connected to the gland packer 10 by a hydraulic line HL, they can be remote from the machine M; and indeed, respective valves V/gauges G for a plurality of the gland packers P may be located at a single control site for ease of control.

In an alternative embodiment, the valve V may be controlled by a computer C; and where the gauge G is substituted by, or operates in combination with, a hydraulic pressure sensor PS connected to the computer C.

As hereinbefore described, the embodiment illustrated has the packer body 20 and pressure ring or plate 40 split into two halves, to enable "retro-fitting" to an existing machine M. It will be readily apparent to the skilled addressee that both the packer body 20 and pressure ring or plate 40 may be of "unitary" construction when they are provided as an original equipment manufacture (O. E. M.) installation for a new machine M.

In an alternative embodiment, one or more return springs 60 (eg., coil springs) can be provided between the packer body 20 and the pressure ring or plate 40 to move the latter towards the former when the supply of pressurised fluid PF is disconnected from the ram assembly(ies)

30.

The gland packer 10 hereinbefore described and illustrated can provide much more accurate and efficient application of the load to the gland packing P in the machine M to which it is fitted; and should the gland packing P leak, the gland packer 10 can be adjusted without the maintenance operator having to come into close proximity with the gland packing P and so can avoid coming into contact with the liquid or other material, eg., being pumped through the machine M.

Various changes and modifications may be made to the embodiments described and illustrated without departing from the present invention.

Claims

1. A gland packer for a gland packing fitted to a housing of a machine, the gland packer including: a packer body mountable on the housing of a machine; a pressure ring or plate slidably mounted on the packer body and engageable with the gland packing; and at least one ram assembly interposed between the pressure ring or plate and the packer body, connectable to a source of pressurised fluid, and operable to move the pressure ring or plate relative to the packer body to apply a load to the gland packing.

2. A gland packer as claimed in Claim 1 , wherein: the packer body is substantially annular, with a substantially central bore therethrough, to receive a rotating shaft joumalled in the housing and to be sealed thereto by the gland packing, and the housing has lugs or other mounting means to enable the packer body to be mounted on studs, bolts, spigots or the like, extending from the housing of the machine.

3. A gland packer as claimed in Claim 1 , wherein: nuts or other fasteners on the studs or the like enable the gland packer to be mounted on the housing so that the pressure ring or plate applies a status pre-load to the gland packing.

4. A gland packer as claimed in Claim 2 or Claim 3, wherein: the packer body has a plurality of cylinders of respective ram assemblies provided at equal radial spacings; and fluid passage(s) connect the cylinders to at least one inlet port to enable the pressurised fluid to cause the ram assemblies to move the pressure ring or plate to apply a load to the gland packing.

5. A gland packer as claimed in Claim 4, wherein: the or each ram assembly has a respective piston, slidably received in, and sealed to, a respective cylinder, where each piston is connected to, or engages a face on, the pressure ring or plate.

6. A gland packer as claimed in any one of Claims 1 to 5, wherein: the source of pressurised fluid has at least one valve to control the flow of pressurised fluid to the gland packer; and at least one gauge means to enable the pressure of the pressurised fluid to be monitored.

7. A gland packer as claimed in any one of Claims 1 to 6, wherein: for original equipment manufacture (O.E.M.) installations, the packer body and the pressure ring or plate, are each provided as unitary components; while for "retro-fit" installations, the packer body and the pressure ring or plate are each provided in two halves which can be secured together.

8. A gland packer as claimed in any one of Claims 1 to 7, wherein: the pressurised fluid is an oil, grease or compressed air.

9. A gland packer as claimed in Claim 6, wherein: the at least one valve and/or at least one gauge are connected to a computer, which has an optional pressure sensor in a line connecting the source of pressurised fluid to the at least one ram assembly.

10. A method of applying a load to a gland packing mounted in the housing of a machine employing the gland packer as claimed in any one of Claims 1 to 9.

11. A machine fitted with the gland packer as claimed in any one of

Claims 1 to 9.