GB2027497A - Retaining sealing glands - Google Patents

Abstract

Mechanical apparatus, such as a fluid flow control valve, comprises a housing 16 with a shaft 12 extending through a gland 32 located in the housing, part of the shaft projecting on the outside of the housing, and a gland retaining member 44 held captive in the housing, and thereby retaining the gland in the housing enclosure, by the combined effect of the engagement of the retaining member in a recess of the housing and on the shaft. Parts of the housing which engage with the retaining member prevent axial movement of the retaining member, and the shaft itself prevents radial movement of the retaining member. The retaining member may comprise a square plate with a bore 52 having a seal 54 receiving the shaft. Alternatively the bore may extend to an edge of the plate to define a U-shaped retaining plate. <IMAGE>

Description

SPECIFICATION Gland retaining means for mechanical apparatus The present invention is concerned with mechanical apparatus of the kind in which there is an enclosure with a shaft extending through a gland located in the enclosure, part of the shaft projecting on the outside of the enclosure. Such apparatus will be hereinafter described as "mechanical apparatus of the kind referred to", but it is to be understood: (a) that the term "shaft" is used to describe any form of shaft-like article, such as an arbor, shaft, spindle, screw or piston rod, and includes articles adapted for rotary and/or axial sliding motion; and (b) that the term "gland" is used in a broad sense to include any device providing a seal between the enclosure and the shaft.

The invention can be used for example, in a valve as used for controlling fluid flow, wherein the valve spindle passes through a gland which comprises a bush in which there is located one or more ring seals, which seal on to the spindle. The bush itself seals in a bore of the valve casing (or in a removable gland housing) usually by means of a further ring seal. A cap must be provided for retaining the bush, and screws are used to secure the cap to the casing or gland housing. In this particu lar application, the valve casing and/or gland housing is the "enclosure"; the spindle is the "shaft" and the bush is the "gland".

There are many kinds of mechanical apparatus where the gland has to be retained by a cap and almost invariably, this is secured to the enclosure by screws or by a screw connection. It is the primary object of the present invention to provide a simple and more economical means of retaining the gland in mechanical apparatus of the kind referred to.

According to this invention mechanical apparatus of the kind referred to is provided with a gland retaining member held captive on the enclosure, and thereby retaining the gland in the enclosure, by the combined effect of its engagements in a recess of the enclosure and on the shaft. Preferably the shaft prevents movement of the gland retaining member in directions radial with respect to the shaft and the engagement of the retaining member in the enclosure recess prevents movements of the retaining member in directions longitudinal with respect to the shaft.

According to a preferred feature of the invention, the gland retaining member is engaged in an effective slot extending in a direction parallel with a diameter of the shaft, the effective slot forming the recess previously referred to. The expression "effective slot" is used, because it may comprise a complete slot bounded by the enclosure above, below and at the sides, but open at one or both ends, or it may comprise only the end parts of such a slot, so that the enclosure does not extend fully across the top of the slot, but only has a pair of inturned lugs on the side walls of the slot, the side margins of the retaining member engaging under these lugs.

Preferably the gland retaining member is a plate-like element having a flat underside adapted to rest on a bearing surface formed on the enclosure. The gland retaining member may be provided with a dust seal for engagement on the shaft.

According to another preferred feature of the invention, the retaining member is formed with a hole, and is threaded on to the shaft, so that it completely surrounds part of the shaft, and hence is prevented from moving in any direction radial with respect to the shaft.

In some instances however, it may be possible to form an open-ended slot in the retaining member for the shaft, so that the retaining member can be slid in a radial direction with respect to the shaft to engage the retaining member with the shaft (so that it is possible to remove the retaining member without removing part of the enclosure) but in that case, some other expedient must be adopted to ensure that the retaining member cannot slide out of the recess. For instance, the retaining member and the recess may have a wedge effect for holding the retaining member in position, or a releaseable key or pin may be provided for securing the retaining member to the enclosure.

In a preferred embodiment of the invention, a fluid flow control valve comprises a valve casing having inlet and outlet openings; a valve seat in the casing between the inlet and the outlet openings; a valve member movable into and out of engagement with the seat; a spindle adapted to cause operation of the valve member by rotation about its own longitudinal axis; a gland housing releaseably secured to the casing and having an opentopped gland chamber therein, with an inwardly projecting collar formed in the gland chamber, a gland bush resting on this collar and being housed within the chamber; a spindle passing through the bush and sealing therewith and having a collar engaging with the underside of the collar in the gland housing to locate the spindle in the casing; the gland housing being formed with an effective slot above the open-topped gland cavity and a gland retaining member engaging in the effective slot, to prevent the gland escaping from the cavity, the top of the effective slot engaging with the top of the retaining member, and the spindle extending through a slot or hole in the retaining member.

In this preferred embodiment, the gland bush may be provided with one or more sealing rings, located in its bore, for engagement on the spindle.

A valve incorporating the invention, will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a section through the upper part of a valve, Figure 2 is an "exploded" view of parts of the valve shown in Fig. 1, Figure 3 is a side view of a gland housing, and Figure 4 is a side view of an alternative gland housing.

Only the upper portion of the valve is shown in Fig. 1, it being assumed that this particular valve is a wedge gate valve as used in water supply pipes. It is to be understood however, that the invention can be applied in the form illustrated in the drawings, to a variety of fluid-flow control valves. Part of the valve casing is shown at 10, and it will be appreciated that the casing is formed with the usual inlet and outlet openings, and with a valve seat, none of which are visible in Fig. 1.

Also, there is a valve member (in this case a wedge) which is adapted for movement in the valve casing, into and out of engagement with the valve seat. The valve member is actuated by a spindle 1 2 which is adapted to rotate about its own longitudinal (vertical) axis, there being a screw connection between the spindle 1 2 and the valve member. All this is conventional, and has only been very briefly described.

The spindle 1 2 passes upwardly through a hole 1 4 in the casing 10, and it then passes through a gland housing 16, which is releas eably secured to the casing 10 by means of set screws 1 8. A rubber "0" ring seal 20 is effective between the casing 10 and the gland housing 16, when the latter is tightened down on to the casing as shown in Fig. 1.

A recess 22 is formed in the underside of the gland housing 16, and the housing has an upstanding boss 24, within which there is formed a bore 26, which provides a gland cavity. An internal collar 28 is formed between the bottom of the gland cavity 26, and the recess 22, and this collar 28 is engaged by a collar 30 formed on the spingle 12, and acts to maintain the correct vertical alignment of the spindle. Moreover, the engagement of the collar 30 on the spindle with the internal collar 28 in the gland housing 16, helps to ensure that the spindle is not distorted, when considerable torque is applied to it for the purpose of opening or closing the valve.

Within the gland cavity 26, there is a gland member 32, which in this construction, is made of nylon or other plastics material. As is clear from Fig. 2, the gland member 32 takes the form of a cylindrical bush, which is a close fit in the cavity 26. A rubber "0" ring 34 seals between the lower end of the bush 32 and the top side of the internal collar 28 of the gland housing 16, when the bush 32 is pressed into the cavity 26.

It will be observed, that part of the spindle 12 extends upwardly through the bush 32, and the upper part of the spindle projects above the top of the housing 16. This top end of the spindle has flat sides 36 for engagement with a detachable cap 38. Two "O" rings 40 and 42 are located in grooves in the bore of the bush 32, and engage with the part of the spindle 1 2 which passes through the bush 32, for the purpose of forming fluid tight seals between the bush and the spindle.

This provides the effective gland, required between the rotatable spindle 12, and the enclosure formed by the casing 10, and the gland housing 1 6. It will be appreciated however, that it is necessary to retain the bush 32 in the cavity 26, and for this purpose a retaining member 44 is provided.

The retaining member 44 is generally in the form of a square plate member, the underside of which is flat and engages on a flat surface 46 (see Figs. 2 and 3) of the boss 24. The latter is formed with inturned lugs 48 at its upper end, so that there are inwardly facing recesses 50 above the surface 46, and below the inturned lugs 48. The retaining plate 44 is of such dimensions, that it can slide into the effective slot formed by the recesses 50, and when in position in this slot, is prevented from moving vertically, by the surface 46, and by the undersides of the lugs 48. In this position, the retaining plate 46 will be effective to prevent the bush 32 escaping from the cavity 26.

The retaining plate 44 has a bore 52, within which is located a rubber dust seal 54, which is adapted to seal on the part of the spindle 12, which extends upwardly through the gland housing 1 6.

In order to assemble the top part of the valve, the spindle 1 2 is fitted into the valve member, before the gland housing 1 6 is applied to the casing 10. The "0" ring seal 34 is placed in the bottom of the cavity 26, and the gland seal bush 32 is then pushed into that cavity. The retaining plate 44 can be slid through an open end of the effective slot formed by the recesses 50, until it is completely housed within the boss 24, in which position it retains the bush 32. Then the gland housing 16, complete with its gland bush and retaining plate 44, is lowered over the projecting upper portion of the spindle 12, to engage the seals 40, 42 and 54 with the spindle, and finally the set screws 1 8 are fitted to secure the gland housing 1 6 to the valve casing.

If it is required to gain access to the valve member, or the spindle, or to sevice the gland, then it is necessary to remove the set screws 18, thus allowing the gland housing 1 6 complete with its gland 32 and retaining member 44 to be removed from the spindle 1 2. Once this has been done, it is possible to slide the plate 44 out of the effective slot formed by the recesses 50, and then the bush 32 can be removed.

It will be appreciated, that in the assembled condition, the retaining member 44 is locked against movement in any direction, by the combined effect of the effective slot formed by the recesses 50, and its engagement on the spindle 1 2. Vertical motion is prevented by the surface 46 and the undersides of the lugs 48, and horizontal motion is prevented by the shaft itself.

Fig. 4 illustrates a gland housing 70 which is generally of similar construction to the gland housing 16, excepting that a complete slot 72 is formed in the upper portion of the housing 70 instead of the effective slot formed by the recesses 50 as shown in Fig.

3. In other words, there is a portion 74 of the gland housing, which extends completely across the top of the slot 72 which receives the gland retaining member. It is necessary to form a bore 76 through this top portion 74, to allow the gland member 32 to pass through it during fitting or removal.

In an alternative construction which is not illustrated, instead of the bore 52 in the gland retaining plate 44, a slot is formed through that plate, which is large enough to accommodate the part of the spindle 1 2 which passes through the plate in the assembled condition, but which extends to one edge of the plate 44, so that it is possible to slide the plate 44 into the effective slot formed by the recesses 50 (or the complete slot 72) after the gland housing 1 6 has been fitted on to the casing, and after the gland bush 32 has been fitted into the cavity 26. However, it is then necessary to ensure that there is sufficient frictional contact between the gland retaining member 44 and the top and bottom surfaces of the slot, to prevent the retaining member 44 being accidentally dislodged. In one arrangement for example, the retaining member 44 may be wedge-shaped in cross-scetion, and the effective slot formed by the recesses 50 may be correspondingly shaped, so that the retaining member has to be driven into the operative position, and can only be dislodged therefrom by a sharp blow. As an alternative, where the retaining member has an opensided slot for fitting around part of the spindle 12, there may be an additional pin or key which passes through the retaining member and through part of the gland housing 16, when the retaining member is in its operative position.

It will be appreciated, that the invention is capable of use with all kinds of glands, including oil seals, and that it is equally effective in relation to shafts which have axial reciprocatory motion as with rotary shafts such as that illustrated in the drawings.

Claims (11)

1. A mechanical apparatus of the kind referred to provided with a gland retaining member held captive on the enclosure, and thereby retaining the gland in the enclosure, by the combined effect of its engagements in a recess of the enclosure and on the shaft.

2. A mechanical apparatus as claimed in Claim 1, in which the arrangement is such that the shaft prevents movement of the gland retaining member in directions radial with respect to the shaft and the engagement of the retaining member in the enclosure recess prevents movements of the retaining member in directions axial with respect to the shaft.

3. A mechanical apparatus as claimed in Claim 1 or Claim 2, in which the gland retaining member is engaged in an effective slot extending in a direction parallel with a diameter of the shaft, the effective slot forming the recess.

4. A mechanical apparatus as claimed in any one of Claims 1 to 3, in which the gland retaining member is a plate-like element having a flat underside adapted to rest on a bearing surface formed on the enclosure.

5. A mechanical apparatus as claimed in any one of Claims 1 to 4, in which the gland retaining member is provided with a dust seal for engagement on the shaft.

6. A mechanical apparatus as claimed in any one of Claims 1 to 5, in which the retaining member is formed with a hole, and is threaded on to the shaft, so that it completely surrounds part of the shaft, and hence is prevented from moving in any direction radial with respect to the shaft.

7. A mechanical apparatus as claimed in any one of Claims 1 to 5, in which the retaining member is formed with an openended slot for the shaft so that the retaining memer can be slid in a radial direction with respect to the shaft to engage the retaining member with the shaft.

8. A mechanical apparatus as claimed in Claim 7, in which the retaining member and the recess have a wedge effect for holding the retaining member in position.

9. A mechanical apparatus as claimed in Claim 7, in which a releaseable key or pin is provided for securing the retaining member to the enclosure.

1 0. A fluid-flow control valve comprising a valve casing having inlet and outlet opeinings; a valve seat in the casing between the inlet and the outlet openings; a valve member movable into and out of engagement with the seat; a spindle adapted to cause operation of the valve member; a gland housing releas eably secured to or integral with the casing and having an open-topped gland chamber therein, with a gland packing or bush housed within the chamber; the spindle passing through the bush and sealing therewith, the gland housing being formed with an effective slot above the open-topped gland cavity and a gland retaining member engaging in the effec tive slot, to prevent the gland escaping from the cavity, the top of the effective slot engaging with the top of the retaining member, and the spindle extending through a slot or hole in the retaining member.

11. A fluid4low control valve as claimed in Claim 10, in which the gland bush is provided with one or more sealing rings, located in its bore, for engagement on the spindle.

1 2. A fluid-flow control valve as claimed in Claim 10 or Claim 11, in which the spindle is adapted to cause operation of the valve member by rotation about its own longitudinal axis, there being an inwardly projecting collar formed in the gland chamber, the gland packing or bush reacting on this inwardly projecting collar, and the spindle having a collar engaging with the underside of the inwardly projecting collar to locate the spindle in the gland casing.

1 3. A fluid-flow control valve constructed and arranged substantially as herein described with reference to the accompanying drawings.