GB2540332A

GB2540332A - Mechanical seal alignment adjustment method

Info

Publication number: GB2540332A
Application number: GB1505587.4A
Authority: GB
Inventors: Colverson Andrew
Original assignee: AES Engineering Ltd
Current assignee: AES Engineering Ltd
Priority date: 2015-03-31
Filing date: 2015-03-31
Publication date: 2017-01-18
Anticipated expiration: 2035-03-31
Also published as: GB201505587D0; GB2540332B; US20160290512A1

Abstract

A mechanical seal, for sealing between an equipment housing 1 and a relatively rotating shaft 2 is provided. The mechanical seal comprises: a gland 3 attachable to the equipment housing; one or more adjustable setting members 5 in the gland 3 and extending therefrom to engage the equipment housing 1; and non-permanent fixing means 7 for detachably attaching the gland 3 to the equipment housing 1.

Description

Mechanical Seal Alignment Adjustment Method Field of Invention

The invention relates to a mechanical seals, which may be used in all types of industries to separate a first liquid from a second liquid wherein the seal is cartridgised to aid correct installation.

Background to Invention

Mechanical seals are commonplace in a multitude of industries for providing a seal between the pump interior and atmosphere. The seal is created by one sealing face rotating against a stationary sealing face. Commonly one of these faces is urged toward the other through the use of springs thus providing the required sealing force. The amount of spring force is optimised so that the operational life of the seal is as long as possible whilst the volume of fluid that passes between the faces is kept to a minimum. The more fluid that passes between the faces means that the operational life will be longer whilst this also means that emissions into the atmosphere and loss or contamination of potentially costly product fluid is increased. If virtually no fluid passes between the faces then the operational life will be shorter due to more of the face material being in contact thereby generating more heat and reducing the length of time before the seal faces are degraded to a point where the leaked volume of fluid is no longer controlled. This is known as a seal failure.

The amount of spring force is controlled in seal designs by maintaining a consistent level of compression through maintaining the physical clearances between components during assembly and operation of the seal. This is commonly done through the use of setting clips which set the distance that the rotary components are spaced from the stationary components; however due to space or design constraints this is not always possible.

The requirement for the mechanical seals to be perpendicular with the rotating shaft of the equipment is important, to ensure internal gaps and spring forces are consistent; this can determine the performance and longevity of the seal.

Applications where the equipment housing to which the mechanical seal fixes exist where the perpendicularity relationship between the seal gland bolting surface and the shaft is inconstant. In order for the seal to interact correctly with the shaft in these applications, alignment control must be possible, where the interaction of the mechanical seal with the equipment housing can be manipulated. This manipulation is required to create the perpendicular relationship that the seal requires with the shaft for optimum running conditions.

Statements of Invention

According to the present invention, there is provided a mechanical seal for location around a rotatable shaft mounted on to equipment housing comprising; a. one or more adjustable setting members to maintain perpendicular alignment of the gland to the shaft; b. non permanent fixing means detachably attaching the gland to the equipment; and c. a gland non-permanently attachable to the equipment housing

Preferably, the setting members locate into orifices in the gland thereby controlling the displacement of the gland against the equipment and setting the perpendicular alignment.

More preferably, the setting members are threaded grub screws and the orifices they reside within are also threaded thereby providing variable contact displacement between the equipment housing.

More preferably, the fixing members are threaded grubs screws that locate on the outer most surface of the setting members in the threaded orifices to secure them in place.

More preferably the setting members are flat point grub screws to maximise the contacting surface between the grub screws and the equipment housing.

Brief Description of Drawing

The accompanying drawings are as follows:

Figure 1 shows the cross section of a mechanical illustrating the current problem of potential gland misalignment;

Figure 2 shows a cross section of an embodiment of the present invention; and

Figure 3 shows a further cross section of the embodiment of Figure 2 and showing the seal fixing arrangement.

Detailed Description

The invention will now be described, by way of examples only, with reference to the accompanying drawings.

The current problem as shown in Figure 1 exists where the equipment housing 1 is not perpendicular to the shaft 2. When the mechanical seal gland 3 is fixed to the equipment housing 1 using fixing members 4 it in turn is not perpendicular to the shaft causing non-concentric sealing faces.

The preferred embodiment of the invention as shown in Figure 2 utilises four settings or alignment members 5 to control the perpendicular relationship between the mechanical seal gland 3 and the equipments rotation shaft 2. The perpendicular relationship between the gland 3 and shaft 2 is controllable as the alignment members 5 can be variably displaced in the gland orifice 6. The alignment members 5 are flat point grub screws which typically occupy, when in position, about half the length of orifice 6.. The described invention allows compensation for angular errors of the equipment housing that may cause a non-perpendicular relationship between the gland 3 and shaft 2.

Locking members 7, also in the form of grub screws are introduced into orifices 6 and caused to bear against the ends of members 5. Members 7 provide a locking mechanism to prevent alignment members 5 from losing their set position and the set perpendicular relationship between gland 3 and shaft 2, which would overtime allow the seal to become loose or detached from the equipment housing and in turn cause the mechanical seal faces to run untrue.

As shown in Figure 3 the preferred embodiment of the invention where the gland 3 is non-permanently fixed to the equipment housing 1 uses four fixing members 8 after the perpendicular relationship between the gland 3 and shaft 2 is set.

Claims

1. A mechanical seal for location around a rotatable shaft mounted on to equipment housing comprising; a. one or more adjustable setting members to maintain perpendicular alignment of the gland to the shaft; b. non permanent fixing means detachably attaching the gland to the equipment; and c. a gland non-permanently attachable to the equipment housing

2. A mechanical seal, according to Claim 1, wherein the adjustable setting members are located in threaded orifices in the gland.

3. A mechanical seal according to Claim 1 or Claim 2, wherein the adjustable setting members are threaded.

4. A mechanical seal according to any of the preceding claims, wherein one or more secondary fixing members are located in the same orifices as the adjustable setting members to provide a locking mechanism.

5. A mechanical seal according to Claim 4 wherein the secondary fixing members have threaded outer diameters in engagement with threaded orifices.

6. A mechanical seal, according to any of the preceding claims, wherein the adjustable setting members are flat point grub screws that contact the equipment housing.

7. A mechanical seal substantially as described with reference to Figures 2 and 3 of the accompanying drawings.

7. A mechanical seal substantially as described with reference to Figures 2 and 3 of the accompanying drawings. Claims

1. A mechanical seal for sealing between a housing and a relatively rotating shaft, the seal comprising; a. a gland attachable to the equipment housing b. one or more adjustable setting in the gland and extending therefrom to engage the housing; and c. non-permanent fixing means for detachably attaching the gland to the equipment housing.