JP3307941B2 - Grand seal assembly - Google Patents

Description

The present invention relates generally to seal assemblies for pumps, and more particularly, but not exclusively, to seal assemblies for centrifugal slurry pumps.

Gland seal assemblies have been used in centrifugal water pumps and centrifugal slurry pumps for many years. A typical prior art ground assembly is shown in FIGS. 1, 2 and 3 are partial cross-sectional front views of a conventional gland seal assembly. Such an assembly generally comprises an outer housing 2, commonly referred to as a stuffing box, which has a cylindrical bore 4 through which a rotating shaft 50, such as a pump shaft, passes. An end wall 35 is provided at one end of the hole. The shaft 50 may or may not have a protective sleeve thereon. Hole 4 and shaft 50
Is usually filled with a packing 5, which may be in the form of a number of packing rings 8. The packing material may vary from case to case, but is usually a weave of fibers having a square or rectangular cross section that can be cut into an annular ring. The packing material is selected for strength considerations, and other lubricants (such as PTFE) are added to reduce friction.

The packing 5 is usually placed in a housing or stuffing box and compressed from the outer end by a gland 9. Since the packing 5 has compressibility,
By moving the gland 9 in and out of the annular gap 7 forming the packing space, the gap between the packing 5 and the shaft (or its sleeve) 50 is adjusted. This adjustment is usually made by an outer bolt (not shown). Fixed packing 5 and rotating shaft
By adjusting the gap 7 between 50 and 50, the leakage from the assembly is adjusted. This leakage is important in some cases to ensure proper cooling of the packing and shaft and to remove heat generated by friction.

This type of seal assembly, when used for a water pump, can use wicked water leaking from the seal assembly during operation to help cool the assembly. Properly lubricated assemblies are needed for long life.

Slurry pumps have other problems because the pumped slurry contains particles. These particles cause additional friction and wear of the packing and sleeve. It is common practice in slurry pumps to inject clean sealing water from an external source into the assembly to reduce these problems and extend the life. This water is injected into the lantern ring assembly 10 via a feed channel 14 to the assembly. The lantern ring assembly may include a lantern ring 11 and a restrictor 12. In FIG. 1, the restrictor 12 is formed of metal, and in FIG. 2, the restrictor 12 is a non-metallic device. FIG. 3 shows the lantern ring 11 spaced from the neck ring 17 by a packing 80. The lantern ring and the lantern restrictor inject water introduced through the flow path 14 into the gap around the shaft or its sleeve. This allows water to pour into the marginal gap between the packing 5 and the shaft 50 and provide adequate and effective lubrication. The construction of both the lantern ring and the lantern ring restrictor allows some sealing water to flow into the pump. This has the desired effect of flushing solids and particles away from the sealing assembly, thus minimizing the risk of slurry contamination in the gland.

The conventional apparatus described above has its own problems in its design, and also causes problems in operation and maintenance of the slurry pump. For example, such devices generally do not provide uniform compression on each packing ring. At high pressures, this problem is exacerbated. The gland usually crushes one or two packing rings more than other packing rings, resulting in uneven sealing and wear. In addition, water usage will vary greatly depending on operator adjustments, the type of packing used, and other variables. Some processes rely on drying the wicked solids in the slurry by removing the water. The additional water used is therefore expensive at a later stage of the process. In addition, there are problems associated with the fact that workers do not always make the appropriate adjustments. The supply of water may be altered or lacking, thereby causing wear and lack of packing and sleeve. Water leaks not only from inside the packing but also from around the outside.

SUMMARY OF THE INVENTION The present invention is directed to alleviating one or more of the problems associated with conventional sealing assemblies.

According to the present invention, a body having a through hole for receiving a rotating shaft, a packing receiving area in the hole, a packing including at least two packing rings, and a seal around the packing ring. A gland seal assembly suitable for use in a slurry pump having a packing sleeve arranged to be able to at least partially convert its axial compression to a radial compression of said packing ring. I will provide a.

Preferably, the packing sleeve has a ring made of an elastomer disposed between the packing ring and the inner surface of the hole. In one form of the invention, the packing sleeve may have a substantially annular shaped outer rim wall. In another form of packing sleeve,
The packing sleeve may have an outer rim wall and a radially inwardly extending side wall at one end of the rim wall. In the assembled position, the side walls may extend from one side of the packing.

In one preferred form, two groups of packing rings are provided, each group associated with one of said packing sleeves. The groups of packing rings may be separated from one another by lantern rings or the like. In one preferred configuration, the lantern ring has a first portion that fits between two groups of the packing rings when in the installed position, and a second portion configured to compress the packing sleeve. Have. It may further include an O-ring or a similar element for providing a seal between the lantern ring and the housing.

The housing may be of any suitable construction. For example, the housing has a body with a hole therethrough for receiving a rotating shaft. The body may include first and second portions each having a packing receiving area within the hole. Each of the first and second parts has an abutment wall, which abuts the end wall of the packing receiving area. It also has operable adjusting means, which allow relative movement between the abutment walls in the axial direction of the bore.

The packing receiving area, when in the assembled position, is an annular area between the inner wall surface of the hole and the outer surface of the rotating shaft,
A side gap may be provided.

Each abutment wall may have a flange that extends substantially radially inward with respect to the inner wall surface of the hole. The abutment flange is preferably formed on the first and second portions of the housing. When in the assembled position, these abutment walls are separated from one another. The holes in the parts of the housing may be open towards each other or may be slightly separated to receive a lantern ring assembly between the parts of the housing.

Each abutment flange, when in the assembled position,
It has a free inner end located adjacent to the surface of the shaft, and can function as a restrictor in cooperation with itself and / or the neck ring.

Conveniently a plurality of packing rings are provided in each part of the housing.

Preferably, one part of the housing is fixed to the pump and the other part is operatively connected to the one part, so that by operating the adjusting means, the other part is Can move axially relative to the part.

The adjusting means may be in the form of a plurality of threaded bolts interconnecting the first and second parts of the housing, whereby the two parts can be moved axially by rotating the bolts. Furthermore, at least one of said parts of the housing may
It has two parts interconnected by bolts, the two parts being able to separate the two parts of the housing for easy access and easy disassembly of the housing .

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 4 is a partial side view of the gland seal assembly of the present invention.

FIG. 5 is a front view of the gland seal assembly shown in FIG.

FIG. 6 is a partial side view showing an improved form of the gland seal assembly of the present invention.

7-9 are side views of an improved lantern ring forming part of the gland seal assembly of the present invention.

FIGS. 4 and 5 show an assembly of the present invention having some of the same features as the conventional seal assembly, and the same reference numerals are used for the same members as in FIGS. . The purpose of any sealing assembly for a pump is to essentially include a pressurized pump fluid. The pressure is reduced by the sealing assembly so that the pressure is at atmospheric pressure outside the seal.

Seal housing or stuffing box 2
Has a hole 4 substantially parallel to the axis of rotation 50 and forms an annular chamber 7. The housing 2 includes a first part
It has a body 3 having 3A and a second part 3B. Flange 1
It has abutment walls in the shape of 4,15, each of which has an inner end 16,17. The inside diameter of the stuffing box is such that it is close to the shaft. The inner ends 16, 17 are configured to cooperate with themselves and / or the neck ring to act as restrictor gaps and to help water run off the slurry. The contact walls 14 and 15 also form shoulders and support the packing 5. The housing or stuffing box is usually made of metal, but other suitable materials can be used. Because the slurry is prone to wear, it is also possible to manufacture the part from a low wear material such as high chrome iron.

The shaft 50 is generally protected by a hard metal or coated sleeve to minimize wear.

The two parts 3A and 3B of the housing body 3 are arranged such that the position of the two housing parts can be adjusted axially with respect to each other by an adjusting device in the form of a bolt 21; Is changed. This controls the gap between the packing and the sleeve or shaft, thereby controlling leakage of the seal assembly. Bolt 21 is the housing part
It is supported by a flange 32 on 3B.

In this structure, the contact wall does not enter the hole of the housing,
Different from conventional ground. Instead, the above structure forms an annular seal chamber on the inner diameter. As shown, the housing parts 36 are split in half and fastened together by the fixing bolts 23. Portion 3A may be similarly split. During maintenance, portions of the housing can be split off from around the shaft 50, thus providing easier access to the housing.

Lantern ring 55 separates the two ends of housing parts 3A, 3B. The outer diameter of the lantern ring is located in both housings or stuffing boxes or in the holes 4
It is located within the outer diameter of and maintains this while ensuring concentricity. Usually the lantern ring is made of metal, but the inner diameter can be coated or provided with a charge to minimize wear of the shaft or sleeve. The radial holes on the inner diameter and the annular groove allow water to be injected into the limiting gap between the packing and the shaft or the packing and the sleeve on both sides of the lantern ring 55. In this way, water can flow both into and out of the pump.

This new structure can be used with any conventional packing type. These are usually braided rings cut in one place and can be mounted around a shaft sleeve. The number of packings 8 can be varied at each end. In the example shown in the figure, two packings are provided at each end.

As shown in FIGS. 4 and 6, a packing sleeve 25 is incorporated around the packing coat at each end of the seal assembly. Two packing sleeves 25 are shown, each associated with a respective group of packing rings 8A, 8B. These packing sleeves 25 are sufficiently elastomeric so that, when the axial movement is effected by the relative movement between the two housing parts, the packing sleeves 25 are first axially compressed. Crushed in the direction. The packing sleeve 25 shown in FIG.
Is a substantially annular ring having an outer rim wall. The packing sleeve shown in FIG. 6 has an outer rim wall and a side wall extending radially inward from one end of the rim wall. In the assembled position, the side walls of the sleeve are:
It is sandwiched between the contact wall of the housing and the packing ring. In other configurations not shown, the side wall of the sleeve can be located adjacent to the lantern ring assembly. When the sleeve 25 is substantially pushed between the outer housing 3 and the packing 5, the axial compression is converted to a radial compression on the packing. The packing is thus compressed axially and radially, and this compression is transmitted from ring to ring and becomes more uniform. A more uniform compression of each packing ring will provide much better control over the sealing assembly and better control over operation and leakage. The packing sleeve also helps seal around the outside of the packing ring to stop uncontrolled leaks.

7 and 9 illustrate various lantern ring configurations that are particularly suitable for using the gland seal assembly of the present invention. In each case, the lantern ring 55 has a first portion 55A that fits between groups of packings 5,
An enlarged portion 55B acting on the packing sleeve 25 to partially compress them.

In the embodiment shown in FIGS. 8 and 9, the O-ring 40 fits between the lantern ring 55 and the housings 3A / 3B, providing an additional seal.

The above construction for the preferred embodiment results in better seal water control, reduced water usage, extended life and reduced slurry ingress, and more uniform wear overall. As evidenced by the fact that the wear of the shaft sleeve extends over all of the packing rings and is not concentrated at one end as is usual in conventional stuffing box constructions. , Packing compression is uniform. The measured ground water injected into the gland can be lower than in a conventional gland configuration, without affecting operation. The structure of the present invention also controls the amount of ground water exiting the gland, both inside and outside the pump. In addition, the structure allows for easier maintenance in that the packing ring is more accessible and the length of the fixed annular sealing chamber is reduced.

Finally, it should be understood that various modifications, improvements and additions may be incorporated into various structures and arrangements of components without departing from the spirit and scope of the invention.

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Claims (8)

(57) [Claims] 1. A gland seal assembly suitable for use in a slurry pump, comprising: a body having a through hole for receiving a rotating shaft; a packing receiving area in the hole; A packing comprising a packing ring, and arranged around the packing ring such that its axial compression can be at least partially converted into a uniform radial compression of said packing ring. And a packing sleeve having properties as an elastomer, and a gland seal assembly. 2. The gland seal assembly according to claim 1, wherein said packing sleeve includes a ring made of an elastomer disposed between said packing ring and an inner surface of said hole. 3. The gland seal assembly according to claim 1, wherein said packing sleeve has a generally annular outer rim wall. 4. The gland seal assembly according to claim 1, wherein said packing sleeve has an outer rim wall and a side wall extending radially inward at one end of said rim wall. 5. A gland seal assembly according to claim 1, wherein two groups of packing rings are provided, each group being associated with one of said packing sleeves. 6. The gland seal assembly according to claim 5, wherein said groups of packing rings are separated from one another by lantern rings. 7. The lantern ring has a first portion that fits between two groups of the packing rings when in the installed position, and a second portion configured to compress the packing sleeve. The gland seal assembly according to claim 6, wherein: 8. The gland seal assembly according to claim 7, further comprising an O-ring or a similar element for providing a seal between said lantern ring and said housing.