WO2018053559A1

WO2018053559A1 - Wet gland stuffing box

Info

Publication number: WO2018053559A1
Application number: PCT/ZA2017/050065
Authority: WO
Inventors: Siegfried Geldenhuys
Original assignee: Mechanical Engineering Transcendent Technology (Pty) Ltd
Priority date: 2016-09-15
Filing date: 2017-09-15
Publication date: 2018-03-22

Abstract

A slurry pump with a sleeve liner through which extends a drive shaft, a lantern ring around the sleeve liner, and passages which direct a flushing fluid through the lantern ring and then through an annular gap between sleeve liner and the lantern ring.

Description

WET GLAND STUFFING BOX BACKGROUND OF THE INVENTION

[0001] This invention relates to a sealing arrangement for a drive shaft of an end suction slurry pump. SUMMARY OF THE INVENTION

[0002] The invention provides an end suction slurry pump which includes a housing, an impeller which is positioned in a chamber in the housing, a drive shaft which is connected to the impeller, a sleeve liner which supports the drive shaft, a wet gland stuffing box which provides a seal on an outer surface of the sleeve liner, a lantern ring, engaged with an outer surface of the sleeve liner, which is positioned between the wet gland stuffing box and the impeller, and chamber structure which extends, at least, circumferentially around, the lantern ring, wherein the chamber structure defines a flushing chamber which is located circumferentially around the drive shaft, a flushing fluid inlet to the flushing chamber, and a plurality of flushing fluid outlets from the flushing chamber, wherein the flushing outlets are positioned circumferentially around the lantern ring at spaced apart intervals and wherein the lantern ring includes a plurality of passages each of which extends between a radial outer surface of the lantern ring and a radial inner surface of the lantern ring and wherein the lantern ring is engineered to define a gap between the radial inner surface of the lantern ring, and an opposing radial outer surface of the sleeve liner and wherein the passages have respective discharge ends which, is in use, direct flushing fluid through the gap. [0003] Preferably the gap comprises an annular cylindrical space.

[0004] The lantern ring is preferably made from an ultra-hard material such as a chrome iron alloy. Preferably the lantern ring has a hardness in excess of 500 Brinel. A seal is preferably provided between the radial outer surface of the lantern ring and an opposing inner surface of the chamber structure. A seal may be provided on the radial inner surface of the lantern ring bearing on an outer surface of the sleeve liner and located between the wet gland stuffing box and said discharge ends of the passages.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The invention is further described by way of example with reference to the accompanying drawings in which :

Figure 1 is a side view in section illustrating a part of an end suction slurry pump according to one form of the invention; and

Figure 2 is a side view in section, on a different scale from that shown in Figure 1 , of flushing chamber structure included in the slurry pump of Figure 1. DESCRIPTION OF PREFERRED EMBODIMENT

[0006] Figure 1 of the accompanying drawings illustrates a portion of a slurry pump 10, according to the invention, from one side and in cross section.

[0007] The pump includes a housing 12 in which is formed a chamber 14 which accommodates an impeller 16. The impeller 16 is mounted to a drive shaft 18. [0008] The drive shaft 18 is supported on a sleeve liner 24. A flushing chamber structure 26 surrounds the sleeve liner 24. The structure 26 is shown from one side and in cross section, on a reduced scale, in Figure 2.

[0009] The structure 26, when installed, defines an annular flushing chamber 28. A flushing fluid inlet 30 extends through a wall 32 of the structure 26. A plurality of flushing fluid outlets 40 which are circumferentially spaced apart from one another extend from the flushing chamber 28 to an inner enclosure 42.

[0010] Engaged with an outer surface 24A of the sleeve liner 24 are a wet gland stuffing box arrangement 46 and a lantern ring 50. These components are positioned inside the enclosure 42.

[0011] The lantern ring 50 is made from an ultra-hard material such as a suitable chrome iron alloy and has a Brinel hardness in excess of 500. Referring also to the insert drawing in Figure 1 , the lantern ring 50 has an outer annular groove 52, an inner annular groove 54 and a number of passages 56 which are circumferentially spaced apart from one another and which place the outer groove 52 in communication with the inner groove 54. An O-ring seal 60, on a radial inner surface 50A of the lantern ring 50, between the stuffing box 46 and the groove 54, bears against the outer surface 24A of the sleeve liner 24. A second O-ring seal 62 on a radial outer surface 50B of the lantern ring 50 provides a seal between an interface of the lantern ring 50 and an inner surface 26A of the structure 26 which bounds the enclosure 42. [0012] The lantern ring 50, on an inner surface 50B between the inner groove 54 and an end surface 66, is dimensioned, relative to the diameter of the outer surface 24A of the sleeve liner 24, to define a gap, which preferably comprises an annular cylindrical space 70 of predetermined dimensions which allows for fluid flow from the groove 54 to a region inside the chamber 14 i.e. to the right in Figure 1 .

[0013] In use of the slurry pump 10 flushing fluid, typically return water, is pumped through the inlet 30 into the chamber 28. From there the flushing fluid passes through the various outlets 40 to the outer groove 52 of the lantern ring 50 and then through the passages 56 to the inner groove 54. Some of the flushing fluid can move past the stuffing material in the stuffing box 46 to the left (in the drawing) and drips from the pump 10. However a primary effect of the introduction of the flushing fluid is to establish flushing fluid flow through the annular cylindrical space 70. This flow takes place in excess of a minimum velocity and is designed to be such that it prevents slurry from flowing (in the drawing) from the right side to the left side i.e. towards the stuffing material in the stuffing box 46. A compromise is struck between the sizes of the annular space 70 and of the outlets 40 on the one hand, and the possible sizes of particulates entrained in the flushing fluid, on the other hand, to ensure that an effective flushing action is achieved i.e. the flushing velocity is adequately high while minimising the likelihood that the outlets 40 or the annular space 70 will become clogged by particulates in the flushing liquid.

Claims

1. An end suction slurry pump (10) which includes a housing (12), an impeller (16) which is positioned in a chamber (14) in the housing (12), a drive shaft (18) which is connected to the impeller (16), a sleeve liner (24) which supports the drive shaft (18), a wet gland stuffing box (46) which provides a seal on an outer surface (24A) of the sleeve liner (24), a lantern ring (50), engaged with the outer surface (24A) of the sleeve liner (24), which is positioned between the wet gland stuffing box (46) and the impeller (16), and chamber structure (26) which extends, at least, circumferentially around the lantern ring (50), wherein the chamber structure (26) defines a flushing chamber (28) which is located circumferentially around the drive shaft (18), a flushing fluid inlet (30) to the flushing chamber (28) and a plurality of flushing fluid outlets (40) from the flushing chamber (28), wherein the flushing outlets (40) are positioned circumferentially around the lantern ring (50) at spaced apart intervals and wherein the lantern ring (50) includes a plurality of passages (56) each of which extends between a radial outer surface (50B) of the lantern ring (50) and a radial inner surface (50B) of the lantern ring (50) and wherein the lantern ring (50) is engineered to define a gap (70) between the radial inner surface (50B) of the lantern ring (50) and an opposing radial outer surface (24A) of the sleeve liner (24) and wherein the passages (56) have respective discharge ends (56A) which, in use, direct flushing fluid through the gap (70).

2. An end suction slurry pump according to claim 1 wherein the gap comprises an annular cylindrical (70).

3. An end suction slurry pump according to claim 1 which includes a seal (62) between a radial outer surface (50B) of the lantern ring (50) and an opposing inner surface (26A) of the chamber structure (26).

4. An end suction slurry pump according to claim 3 which includes a seal (60) on a radial inner surface (50A) of the lantern ring (50) bearing on the outer surface (24A) of the sleeve liner (24) and located between the wet gland stuffing box (46) and said discharge ends (56A) of the passages (56).