WO1989012771A1

WO1989012771A1 - Gland sealing compound injector and seal

Info

Publication number: WO1989012771A1
Application number: PCT/GB1989/000675
Authority: WO
Inventors: Charles David Campbell Hardy
Original assignee: Tom-Pac (Uk Distribution) Limited
Priority date: 1988-06-17
Filing date: 1989-06-16
Publication date: 1989-12-28
Also published as: GB8814406D0; AU3840089A

Abstract

A gland sealing compound injector apparatus comprising means for injecting gland sealing compound into a gland of a machine via an aperture in the stationary part of the machine, whereby the machine may continue to operate during insertion of the gland sealing compound.

Description

GLAND SEALING COMPOUND INJECTOR AND SEAL

The present invention relates to a gland sealing compound injector and a seal .

Glands are known for sealing between the rotating and stationary parts of rotating machinery, for example for sealing between a rotatable shaft and a housing of a pump. The gland _r for example, prevents the leakage of liquid from within the pump along the rotating sha t. Various methods of gland sealing are known, including mechanical seals, and various forms of solid packing such as lengths of braided compression packing. These allow the moving part and stationary part to move relative to one another without leakage of material, typically a fluid, out of the apparatus.

Although the packing material is commonly a solid woven and lubricated material, a self lubricating gland sealing compound has been widely used in which a stuffing box surrounding, for example, a rotating shaft, is packed with the sealing compound to prevent leakage of material past the gland. Such self lubricating gland sealing compound (usually of putty¬ like consistency or even more solid) typically includes lead, graphite, molybdenum disulphide, various oils and polytetraf lurorethylene as lubricants, and fibrous material such as chrysotile or aramid and carbon, fibres as binder.

Such material has been very successful as a gland sealing material, but clearly further material must be added to the gland from time to time to make up for any losses. Commonly this requires dismantling of the gland and this will usually require the machine itself - -

to be stopped. This can be inconvenient, particularly in a large plant where, for example, a large number of pumps are involved.

The present invention provides according to a first aspect a gland sealing compound injector apparatus comprising means for injecting gland sealing compound into a gland of a machine via an aperture in the stationary part of the machine, whereby the machine may continue to operate during insertion of the gland sealing compound.

In a preferred arrangement the injector apparatus is attached to a bore passing from the outside through the stationary part to a gland cavity (stuffing box), the injector apparatus, in use, injecting gland sealing compound into the cavity. The injector apparatus may be connected directly to the stationary part or via a flexible or rigid tube, and may include a housing for a closed cartridge of gland sealing compound, and there may be provided motor means for continuously or intermittently injecting the gland sealing compound into the housing. The motor means may include an electric, pneumatic or hydraulic motor or hydraulic cylinder and where the sealing compound is contained in the cartridge, may include a screw jack arrangement driven by the motor, the screw jack arrangement or hydraulic cylinder being used to move a moveable diaphragm (piston) within the cartridge to eject the gland sealing compound from the cartridge and inject it under pressure into a gland stuffing box to maintain automatically a continuous seal with no manual or outside intervention, or need to close the plant down.

A problem has also arisen in mounting a cartridge and nozzle together and sealing them so that the material within the cartridge forced out of the cartridge under pressure, does not leak past the joint between the nozzle and the cartridge.

Thus seal means which may be provided between a cartridge and a nozzle, the seal means being generally annular in shape, and including an outer sealing surface and a radial or substantially radial sealing surface, the portion mounting the outer sealing surface being flexible so that, under pressure, the portion flexes to. force the outer sealing surface into sealing engagement with an adjacent surface, and the portion mounting the radial or substan ially radial sealing surface being movable so that under pressure the portion moves to force the radial or substantial radial sealing surface into sealing engagement with an adjacent surface.

In a preferred arrangement, the portion mounting the radial sealing surface comprises the seal means itself so that the seal means tends to move, under pressure, in a direction so that the radial sealing surface is forced into sealing engagement with an adjacent surface.

Where the seal means is intended for use in sealing a cartridge to a nozzle, the outer sealing surface may be used to seal with an adjacent surface on the nozzle, and the radial sealing surface may be adjacent the end surface of the cartridge so that said end surface of the cartridge forms the adjacent surface to the radial sealing surface.

An annular extension or skirt may be provided to surround a cartridge in engagement with the seal means, the annular extension including an inwardly directing annular lip to grip the outer surface of the cartridge.

Preferred arrangements of the invention will now be described by way of example only and with reference to the accompanying drawings in which:

Figure 1 shows a diagramatic front view of a first injector according to the invention attached to a machine with rotatable shaft, the stuffing box of which is shown in cross section,

Figure 2 shows various forms of motor which may be used to drive the apparatus of Figure 1,

Figure 3 shows an. alternative drive arrangement,

Figure 4 shows a perspective view, of the injector of Figure 1, together with a cartridge,

Figure 5 is an axial section of a seal means according to the invention in engagement with a cartridge and nozzle,

Figure 6 is an axial section of the seal of Figure 5,

Figure 7 is a section through the wall of the seal of Figures 5 and 6,

Figure 8 is an axial section of a second injector according to the invention, and,

Figure 9 is an axial section of a cartridge for use with the injector of Figure 7, with the piston means shown in its opposite positions.

Referring to Figure 1 there is shown an injector apparatus 10 attached to a machine 11 (typically a pump) with a rotatable shaft 12, a fixed part 13 of the machine 11 including an annular cavity forming a stuffing box 14 surrounding the rotatable shaft 12. The stuffing box 14 is closed by a conventional annular gland follower 16 bolted by bolts 17 to the fixed part 13 of the machine 11.

In a conventional gland arrangement the stuffing box 14 would be filled with a braided gland packing, but in some circumstances this is replaced by gland sealing compound which is normally inserted by hand.

In the present arrangement, however, a threaded bore 18 is provided through the fixed part 13 into the stuffing box 14. The threaded bore 18 is connected to the injector apparatus 10 by means of a flexible or rigid piping 19, the piping connecting with the threaded bore 18 by means of a threaded connector 21 incorporating a shut off valve 22.

The injector apparatus 10 will be more clearly understood with reference to Figures 1 and 4 and comprises a housing 23 of generally hollow cylindrical form having an open side 24, the housing removeably mounting a cylindrical cartridge 26. The lower end of the housing 23 incorporates a removable conical nozzle part 27 with which an opening in the lower end of the cartridge 26 sealingly engages. The nozzle part 27 is hollow and has a threaded outer lower end for threadedly engaging with a connector 30 attached to the pipe 19. Integral with the top of the housing 23 is a screw jack 28, the screw jack 28 comprising a gear box 39 which operates the screw shaft 29, to the lower end of which is attached a plunger 31, the plunger 31 bearing on a moveable diaphragm 32 in the form of a piston inside the cartridge 26. The screw shaft 29 engages with a pinion 33, the pinion being rotatable by means of a primary pinion mounted on a shaf 34. The screw shaft 29 is protected by means of a 'see through' cover 36 which allows its position to act as an indicator of the volume of compound remaining in the cartridge 26.

The shaft 34 may be rotated by various means as is illustrated in Figures 1 and 2. The shaft 34 may be rotated by means of a ratchet lever 37, by means of a handle 38, or as is illustrated in Figure 2, by means of a hydraulic motor 41, air motor 42, or electric motor 43.

The injector apparatus 10 may be attached to the machine 11 itself or to a frame adjacent to the machine by means of fixings in the form of bolts through suitable bores 44 in the housing 23.

There- may .also be provided a leakage detector 46 for detecting leakage of liquid from within the machine 11 past the gland as is well known, and this leakage detector may be connected to a relay control for operating the motors 41-43. As an alternative, the motors 41-43 may be automatically controlled by means of a timer 47.

The housing and associated parts may be made of any suitable material, for example, cast metal such as cast iron or aluminium or may be fabricated from steel or other sheet material or moulded of plastic. Some considerable strength is necessary because the pressure required to make the gland sealing compound flow into the gland is at least 30 MN/m .

The apparatus thus far described may be operated as follows. We will assume that the gland initially comprises a stuffing box 14 in which gland sealing compound will initially be inserted by hand. Such a stuffing box sometimes will not incorporate a bore such as threaded bore 18 and so as a irst step to applying the injector apparatus 10 to the machine 11, it is necessary to provide said threaded bore 18. In this case, therefore, initial installation of this injector apparatus 10 will sometimes require the machine 11 to be taken out of service.

The pipework comprising piping 19, threaded connector 21 shut off valve 22 is attached to the threaded bore 18 and the injector apparatus 10 is mounted to a suitable adjacent position. The conical nozzle part 27 is then connected to the piping 19 by means of the connector and a full cartridge 26 is inserted into the housing 23 through the open side 24, the end of the cartridge 26 closed by the piston 32 being uppermost. Normally, the lower end of the cartridge 26 will incorporate some aperture which has to be pierced before the cartridge is inserted into the housing.

For initial installation of the compound (and perhaps using a second injection apparatus) it may have attached thereto a plastic nozzle portion 48 shown in Figure 4, which may be cut so as to provide a square section aperture at the lower end of the nozzle portion 48 of suitable size for the stuffing box 14. The gland follower 16 is removed and a suitable length of compound extruded from the plastic nozzle. This extruded length of compound is carefully wrapped around the shaft 12 and pushed into stuffing box 14. Using the gland follower 16 to ensure that it is pushed fully home to the bottom of the stuffing box. When the gland follwer 16 has been tightened home with the nuts 16, this initial installation is complete.

Once the full cartridge 26 containing the gland sealing compound is inserted, the shaft 34 is rotated by whatever means is provided so that the plunger 31 engages with the piston 32 within the cartridge 26 and this movement continues until gland sealing compound from the cartridge has passed through the nozzle 27, through the piping 19, through the thread bore 18 and into the stuffing box 14.

The machine 11 may now be set in operation. Further gland sealing compound may be injected into the gland either continuously, but very slowly or intermittently either at regular predetermined intervals, for example, maintenance intervals by the automatic timer 47, or under the control of the leak detector 46 which detects leakage of material from within the machine 11.

Figure 3 shows an alternative arrangement of injector apparatus 10 in which the screw jack 28 and motors 41- 43 are replaced by a double acting hydraulic cylinder 48 operated by means of a hand pump 49 or a hydraulic power supply which may be controlled, for example, by the control means 46 or 47. The double acting hydraulic cylinder 48 acts directly on the moveable piston 32. Whilst we have shown the injector apparatus 10 permanently connected adjacent machine 11, it may be removed from the particular machine 11 after the shut off valve 22 has been closed by unscrewing the threaded connector 21 and may be used to similarly inject gland sealing compound into other glands.

In addition, the injector can be mounted remotely (typically up to 20m or more away from the gland) for use on submerged or otherwise inaccessible equipment.

By use of the injector apparatus of the invention, a gland can be arranged so as to be efficiently operated at all times.

Refering now to Figures 5-7, there is disclosed a cartridge 100 which may be similar to the cartridge 26, and a nozzle 101 which may be similar to the nozzle part 27. A seal means 102 moulded of a plastics material is provided between the cartridge 100 and nozzle 101 to seal them together and to prevent material within the cartridge from passing between the cartridge 100 and nozzle 101.

The seal means 102 is generally annular in shape and is made of a flexible material such as a moulded plastics material. Referring to Figure 7 in particular, which shows a section through the wall of the seal means 102, there is provided an outer annular surface 103, an inner annular surface 104, the outer annular surface 103 carrying, adjacent to the end which is closest to the nozzle 101, an outer sealing surface 106. This outer sealing surface 106 is provided on an enlarged radial portion of the seal means 102. The outer sealing surface 10b is cylindrical.

The seal means 102 also includes, on its inner annular surface 104, a radially extending sealing surface 107. This surface 107 faces, in Figure 5, towards the cartridge 100. The radial extent of the radial sealing surface 107 is generally the same as the thickness of the end wall 114 of the cartridge 100.

Referring to Figure 7, it will be seen that to the right of the radial sealing surface 107, the thickness of the seal means 102 is less and forms an annular extension or skirt 108, the right most inner edge of the skirt 108 including an annular lip 109 of a part circular (when viewed in Figure 7) section. In its natural state, shown in Figure 7, the radius from the axis of the seal means of the innermost point of the annular lip 109 is less than the the radius of the outside of the wall of the cartridge 100.

In use, and referring particularly to Figure 5, the seal means 102 is inserted into a corresponding annular skirt portion 111 of the nozzle 101. The inner diameter of the skirt portion 111 is substantially the same as the outer^" diameter of the outer annular surface 103 of the seal means 102. The cartridge 100 is then inserted so that its front circular end 114 enters into the skirt 108 of the seal means 102, in doing so, expanding the skirt 108 by engagement with the annular lip 109. The annular lip 109 by gripping the outer surface of the cartridge 100 maintains it in position during the mounting operation.The cartridge 100 is pushed inwardly until its edge 114 abuts the radial sealing surface 107 of the seal means 102.

Means is provided (not shown) adjacent the end of the cartridge 100 opposite the nozzle 101 to prevent rearward movement when the cartridge 100 has been properly engaged with the nozzle 101.

In this position the seal means 102 provides a seal, but the effecti eness of the seal is improved during further use. In further use, a piston 113 of the cartridge 100 is moved into the cartridge 100 and thereby pressurises the material within the cartridge 100 as is well known. Thus, the material passes out of the cartridge and into the nozzle 101 under pressure. This pressure is applied to the seal means 102. The pressure within the seal means 102 has two effects. Firstly, pressure is able to get between the axial end 112 of the seal means 102 and the associated surface of the nozzle 101 and this urges the seal means 102 backwards (that is to the right). This forces the radial sealing surface 107 into sealing engagement with the edge 112 of the cartridge 100 and improves the seal between those two surfaces. The seal is improved the higher the pressure applied and so there is a self compensating arrangement.

Similarly, the pressure applied within the seal means 102 causes the part of the seal means 102 mounting the outer sealing surface 106 to distort outwardly, in other words, the sealing means 102 expands slightly and this forces the outer sealing surface 106 into sealing engagement with the adjacent surface of the skirt 111 of the nozzle 101. Once again, the greater the pressure within the seal means 102, the greater the sealing effect between the outer sealing surface 106 and the skirt 111.

We now refer to the second embodiment of the invention illustrated in Figures 8 and 9. Similar parts are similarly numbered to the embodiments of Figures 1 to 7. The major difference between the embodiment of Figures 8 and 9 and the earlier embodiments is the design of the cartridge 26.

In the axial section of Figure 8, one can see details of the gear box 39; the shaft 34 carries a pinion 51 which drives a further pinion 52 connected to the screw shaft 29. The ratio of teeth on the pinion 52 & 51 is 1.5:1 so that the gerabox is a right angle reduction gearbox of 1.5:1 ratio.

The cartridge 26 comprises in this case a metallic body having a first cylindrical body portion 53 which is mounted in the housing 23 as before, and a conical end portion 54 of shallow angle, the conical end portion 54 carrying a cylindrical nozzle 55. The cylindrical nozzle 55 includes a stepped down portion 56. The body of the cartridge 26 is of strong metal and there is mounted within the cartridge 26 a movable diaphragm 32 in the form of a cylindrical piston 57 which includes a flexible forwardly disposed annular sealing lip 58, and a further plug 59. The cylindrical piston 57 may be of metal or suitable rigid plastics such as low density polythene, and the plug 59 may be of a polyether compound which is relatively soft. Its volume matches the volume of the conical end portion 54.

The means for sealing the nozzle 55 to the connector 30 is clearly seen from Figure 8, comprising an '0' ring seal surrounding the outer diameter of the stepped down portion 56, and it will be understood tht the inner diameter of the step down portion 56 through which the material flows, matches exactly that^* of the inner diameter of the connector 30.

Thus in use the cartridges mounted within the injector apparatus 10 much as before, the outer diameter of the stepped down portion 56 engaging the '0' ring 60, and the handle 38 is then wound so that, via the gearbox 39 the screw shaft 29 is engaged behind the cylindrical piston 57. When all is properly seated, further rotation of the handle 38 will cause the screw shaft 29 to push the cylindrical piston 57 to the left in Figure 8, thereby ejecting the sealing compound from within the cartridge 26.

Now it is necessary because of the solid nature of the sealing compound, to provide a shallow angled conical end portion 54 and as the portion 57 cannot enter the conical end portion 54, the material within this conical end portion 54 would be wasted. However, As the cylindrical piston 57 moves to the left in Figure 8, at some point the plug 59 enters the cylindrical end portion 54. Because the plug 59 is of conpressable material it will continue to move into the conical end portion 54 and when the cylindrical piston 57 reaches the conical end portion 54 (where it jams) the plug 59 completely fills the conical end portion 54 so as to ensure that all of the material in the cartridge has been ejected.

Claims

1. A gland sealing compound injector apparatus comprising means mounted to a machine for injecting gland sealing compound into a gland cavity provided between stationary and moving parts of the machine via an aperture in the stationary part of the machine, whereby the machine may continue to operate during insertion of the gland sealing compound into the gland cavity.

2. A gland sealing compound injector apparatus as claimed in claim 1 characterised in that the machine includes a bore passing from the exterior of the machine through the stationary part to a gland cavity.

3. A gland sealing compound injector apparatus as claimed in claims 1 or 2 characterised in that the injector apparatus is connected directly to the stationary part of the machine.

4. A gland sealing compound injector apparatus as claimed in claims 1 or 2 characterised in that the injector apparatus is connected to the machine via a tube.

5. A gland sealing compound injector apparatus as claimed in any of claims 1 to 4 characterised by a housing for a closed cartridge of gland sealing compound.

6. A gland sealing compound injector apparatus as claimed in claim 5 characterised by a motor means for continuously or intermittently injecting the gland sealing compound into the housing.

7. A gland sealing compound injector apparatus as claimed in claim 6 characterised by screw means, the screw means being rotatable to move a moveable diaphragm within the cartridge to eject the gland sealing compound from the cartridge and inject it under pressure into a gland stuffing box to maintain automatically a continuous seal.

8. A gland sealing compound injector as claimed in claim 7 characterised in that the cartridge includes a conical end portion adjacent an output, and a deformable plug is mounted between said moveable diaphragm and the gland sealing compound within the cartridge or forms part of the moveable diaphragm whereby as the deformable plug is moved with the moveable diaphragm into engagement with the conical end portion, it deforms so as to ensure that the gland sealing compound within the conical end portion is ejected from the output.

9. A gland sealing compound injector as claimed in claim 7 or 8 characterised in that gearbox means is attached to said screw means, said screw means being rotatable via said gearbox means.

10. A gland sealing compound injector apparatus as claimed in claim 9 characterised in that said gearbox means is a right angled reduction gearbox.