GB2417992A

GB2417992A - A self-contained flow inducing system

Info

Publication number: GB2417992A
Application number: GB0418413A
Authority: GB
Inventors: Alan James Roddis
Original assignee: AES Engineering Ltd
Current assignee: AES Engineering Ltd
Priority date: 2004-08-18
Filing date: 2004-08-18
Publication date: 2006-03-15
Anticipated expiration: 2024-08-18
Also published as: GB2417992B; GB0418413D0

Abstract

A self-contained unit, with an integral renewable power supply (35) and a power back up supply (34) which powers a rotational drive mechanism (32) in non-contacting rotational connection to an impeller. Said impeller is cited in the flow path of a fluid and herewith promotes fluid movement within said flow path.

Description

24 1 7992 A Self Contained Flow Induced System

Field of the Invention

This invention relates to mechanical seals and seal support systems, especially when the mechanical seal contains two or more sets of mechanical seal faces and the use of a flow induced fluid supply is deemed advantageous.

Background to the Invention

A Mechanical seal comprises a "floating" component which is mounted axially movably around the rotary shaft of, for example a pump and a "static" component which is axially fixed, typically being secured to a housing. The floating component has a flat annular end face, i.e. its seal face, directed .

towards a complementary seal face of the static component. The floating .

component is urged towards the static component to close the seal faces together to form a sliding face seal, usually by means of one or more .. springs. Alternatively, instead of one or more springs, a metal bellows unit may be employed as the floating component. . ë

A

I- 20 In use, one of the floating and static components rotates; this component is therefore referred to as the rotary component. The other of the floating and static components does not rotate and is referred to as the stationary component.

Those seals whose floating component is rotary are described as rotary seals. If the floating component is stationary, the seal is referred to as a stationary seal.

If the sliding seal between the Rotary and Stationary components are assembled and pre-set prior to despatch from the Mechanical seal manufacturing premises, the industry terminology for this is "cartridge seal".

If the Rotary and Stationary components are despatched individually (unassembled) from the Mechanical seal manufacturing premises, the industry terminology for this is "component seal".

Mechanical seals often include a gland member, which connects the seal to the stationary part of the rotating equipment. Said gland member includes at least one, preferably two connecting ports which radially connect the inner most region of the gland to the outer most region. Said connection ports are then typically connected from the seal gland to a seal support system via appropriate pipe work. The seal support system provides cool, clean fluid to the mechanical seal, which in turn lubricates and cools the seal faces often resulting in an extension of seal life.

Often, in such an application the lubrication fluid heats up and its density changes. This density change promotes convection, in a closed circuit system. Said hot fluid convects back to the seal support system from the seal and said cooler fluid convects from the seal support system to the seal. . :

Unfortunately, there are many inherent disadvantages with fluid convection in . . : such applications, not least the system is unreliable and not efficient at A..

. 20 removing heat from the seal in a timely manner.

Forced circulation systems have been developed to overcome said weaknesses of the convection system. Said forced circulation is typically created from a rotating mechanism positioned within the mechanical seal, or via a pump mounted in an external system. Respective reference is made to our co-pending application US 6,428,011.

Again, there are inherent issues with both devices, herewith explained; Firstly, the forced circulation system created by the internal parts of a mechanical seal only operates when the seal is rotating. When the seal, and corresponding equipment shaft is stationary, the system does not circulate fluid. Furthermore, in some physically restricted applications, there is no room to incorporate such a device into the mechanical seal.

Our co-pending application US 6,070,880 offers an alternate for applications were there is no room to incorporate such a flow induced device into a mechanical seal. Unfortunately this arrangement is costly and time costing to set up. Again it suffers from the problem that when the equipment shaft is not rotating, there is no flow induction.

The forced circulation system created by an external pump adjacent or inside/mounted on the seal support system also has issues, not least the fact that the system requires an electrical supply to drive the pump which is used to circulate the fluid. This is often a big problem in plants, specifically if said . plant atmospheres are potentially explosive. In such cases all electrical ë supplies have to be vetted by a team of suitably qualified plant personnel A. .. and certified to be intrinsically safe . :e

A system which can circulate fluid around a closed circuit, as found between ë : a mechanical seal and seal support system, without requiring an additional A..

electric supply, is deemed particularly advantageous.

Further benefits are apparent if said unit is self contained, intrinsically safe and easy to install.

Statements of the Invention

According to the present invention there is provided a self-contained flow induced system, which may be connected in the closed circuit of a mechanical seal and seal support system. Preferably, said unit is powered by a solar cell and incorporates a backup battery system therefore hard electrical wiring is not required. Furthermore, preferably, said unit is intrinsically safe and thus can be universally installed in hazardous and potential explosive environments.

Although reference is made herein to impeller mechanism to promote flow within the unit, it would be understood that any form of flow generation impeller or such device may be provided. s

Preferably the impeller is radially restrained within an orifice of the housing and axially restrained by one or more circlips.

Preferably the impeller is rotationally driven by a suitable noncontacting device, such magnetic attraction between the drive motor and driven impeller, thereby emitting the need for a sealing device between said items.

Preferably, the drive motor is sealed within the confines of the housing, with . the use of a suitable sealing device such as an elastomeric toroid or gasket. e.e

Preferably the solar cell is a robust design and integrally mounted on the . . housing such that all wires from the solar cell to the other parts on the assembly, are protected and preferably sealed from contact with the : housing. A..

. 20 Preferably the solar cell, backup battery and drive motor are mounted integrally in the housing.

The invention thereby provides a fluid movement device in the form of an integral, self contained, self-powered flow circulation device, which is of the invention.

Description of the drawings

The accompanying drawings are as follows: Figure 1 is a schematic view of a mechanical seal connected to a seal support system, in a typical rotating equipment application; Figure 2 corresponds to Figure 1 and shows the seal and system arrangement with the addition of the integral, self contained flow induction unit, of the first embodiment of the invention; Figure 3 corresponds to Figure 2 and shows an enlarged isometric view of the self-contained flow induction unit.

Figure 4 corresponds to Figure 3 and shows an exploded isometric view of the self-contained flow induction unit.

Figure 5 corresponds to Figure 3 and shows a longitudinal cross section view of the self-contained flow induction unit.

Figure 6 corresponds to Figure 2 and shows an alternate design and location of the solar unit of the invention, illustrating the second embodiment of the invention.

. Figure 7 corresponds to Figure 3 and shows a wiring schematic of the ë invention. A. -

Detailed description of the Invention

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

*'. 20 Referring to Figure 1 of the accompanying drawings, there is illustrated a prior art example of a mechanical seal assembly 10, which is installed on a piece of rotating equipment such as a pump (not shown). The mechanical seal 10 is connected to a seal support system 11 via feed pipe work 12 and return pipe work 13.

In operation, the seal support system 11 is filled with a lubrication and cooling fluid, such as water. As the mechanical seal 10 rotates with the equipment shaft, the mechanical seal faces generate heat. This warms the lubrication and cooling fluid supplied by the seal support system 11 and typically in contact with one or more sets of mechanical seal faces. In practice the lubrication fluid is subject to convection laws, where the hot fluid rises in the return pipe work 13. This tends to pull the cooler fluid from the seal support system 11 through the feed pipe work 12 into the mechanical seal assembly 10.

Figure 2, corresponds to Figure 1 and shows the mechanical seal 10 and seal support system 11 with the addition of the self contained flow induced unit 20 in the feed pipe work 12. Clearly, the position of such a unit 20, could be at any position with the cooling circuit.

Figure 3 corresponds to Figure 2 and shows an enlarged isometric view of the self-contained flow induction unit 20.

From Figure 3, the solar cell 21 is attached to the side of the flow induction . unit body 22 of the first embodiment, by one or more mechanical means r such as a screw 23. Once again, this is by way of example only, as the solar : unit could be positioned at any location. Figure 6 provides a further example of such a position.

Figure 3 further shows a sealing cap 24 axially restrained by a circlip 25.

Ail- 20 Said sealing cap 24 contains an elastomeric member, which radially connects the outer most radial surface of the sealing cap 24 to inner most radial surface of the body 22.

This sealing cap 24 prevents debris from entering the assembly 20 and seals the electrical connections of the unit 20 from the atmosphere.

Figure 4 corresponds to Figure 3 and shows an exploded isometric view of the self-contained flow induction unit 20. From Figure 4 the impeller drive 30 contains one or more magnets 31. Said drive sub-assembly 32 is rotationally driven by the motor 33. Said motor is connected to a suitable power source 34, which could be a battery. Said power source 34 is ideally chargeable and connected to a secondary power source such as a solar cell 35 via an appropriate charger unit 36.

The solar cell 35 is mounted to the body 37 via screw 38. Between the solar cell 35 and body 37 is a elastomeric member 38, which may be considered as a compressible gasket 38. This sealing device 38 prevents debris from entering the assembly 20 and seals the electrical connections of the unit 20 from the atmosphere.

From Figure 5, impeller 39 rotates in an orifice 40 in body 37, rotationally driven by the non-contacting drive assembly 32. Impeller 39 is axially "en 15 restrained by a suitable means such as a circlip 41, thereby preventing it from axially moving in operational situ or transit. Clearly, impeller 39 should . be made from a suitable magnetically attracting material to enact rotational movement from the rotational drive assembly 32. Alternatively the impeller A 'a: 39 should contain attracting magnets to magnetic members of material to - . ..

20 enact the same.

Figure 5 also shows a threaded inlet orifice 42 and outlet orifice 43 which allows the unit to be connected to feed or return pipe work. As the impeller 39 rotates it induces movement in the fluid 44, which enters the inlet orifice 42.

Figure 6 corresponds to Figure 2 and shows an alternate design and location of the solar unit 50 of the invention, illustrating the second embodiment of the invention.

From Figure 6, the solar unit 50 is a flexible design, which can adapt to a form, such as the curved surface on the seal support system vessel 51. This has the advantage of a larger solar area available to create power and a smaller pipe connecting assembly 52.

Figure 7 corresponds to Figure 3 and shows a typical wiring schematic of the invention.

From Figure 7, the solar cell 60 is connected to the charger unit 61, backup battery supply 62 and motor drive assembly 63.

Figure 7 further shows an optional addition, which is the inclusion of a REID (Radio Frequency Identification) device 70 or suitable blue tooth device and/or signal amplifier and/or antenna, for remotely sensing the condition of the motor drive assembly 63, and/or power supply 60 and/or 62. ë . ë ë

The invention therefore provides a self-contained unit, with an integral renewable power supply and power back up supply which powers a rotational drive mechanism in non-contacting rotational connection to an ë impeller. Said impeller is cited in the flow path of a fluid and herewith promotes fluid movement within said flow path. ..

The experienced reader will relate to the benefits of the invention when used in a number of industrial applications, particularly when used in the connecting pipe work of a mechanical seal to a seal support system.

There are many further industrial uses for such a device. One application is the circulation of a fluid, such as oil, in a conveyor system, where the oil is used to lubricate one or more bearing assemblies, which support the conveyer rollers.

Claims

1. A fluid flow induced unit comprising of; - a body which includes an orifice - a renewable power device - a rotational drive mechanism - and an impeller, cited in the fluid flow path.

2. A fluid flow induced system, in accordance with claim 1, whereby the renewable power device comprises of a solar cell.

3. A fluid flow induced system, in accordance with claim 1, whereby the body includes at least one office with at least one threaded connection on one of .

:.: .. the axial ends of said office.

. 15

4. A fluid flow induced system, in accordance with claim 1, whereby the . rotational drive mechanism is adjacent and in a contacting relationship with the driven mechanism, which is an impeller used to promote fluid flow upon rotational input. -. 20 .

5. A fluid flow induced system, in accordance with any preceding claim, whereby the renewable power supply is connected to a charger unit which is connected to a rechargeable power supply, and at least one of the aforementioned devices is connected to a rotational drive device such as a motor assembly.

6. A fluid flow induced unit in the form of a non-contacting rotating drive and driven member, said driven member is cited in the fluid flow path and said driven member is powered from a self-contained and rechargeable power source as claimed in any of the preceding claims.