AU3392599A

AU3392599A - Reverse impulse purging valve

Info

Publication number: AU3392599A
Application number: AU33925/99A
Authority: AU
Inventors: John Thomas Beer
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-06-12
Filing date: 1999-06-09
Publication date: 1999-12-23

Description

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A USTRALIA Patents act 1990 COMPLETE

SPECIFICATION

STANDARD

PATENT

RE VERSE IMP ULSE P UR GING VAL VE The following statement is a full description of this invention,including the best method of performing it known to me: 1 Reverse Impulse Purging Valve This invention is a device whereby, when incorporated in the suction line of a fluid pumping system will keep the suction line and suction filter or strainer free from blockages.

In dewatering systems, particularly in underground mining filter/strainer blockages are frequent and subsequent pump damage and resulting foodin occurs regularly.

Several attempts have been made to reduce this problem, however most have concentrated on preventing foreign matter accumulatina on the filter or strainer surface. This device allows foreign matter to accumulate on the filter or strainer surface and utilises the ensuing phenomenon, an increase in vacuum within the suction line, to actuate cleaning- purging cycle.

The purging medium may be compressed air or other pressurised fluid, which is permitted to enter the suction line by means of a main valve contained within the device. In this form of the invention the entire mechanism is rigidly mounted to a tube of corresponding cross-section area to that of the suction line, and is fixed therein at both ends by means of 15 an acceptable coupling mechanism. Refer Drawing A.

Drawing IA general layout shows an acceptable position for Reverse impulse Purging Valve 3 within the suction line 5 of a typical pumping system. In this case the pump 4 is compressed air driven and the air supply for the Reverse Impulse Purging Valve 3 is taken from a position on mains air supply 1 prior to the pump 4 mechanism. Air is delivered to 20 Reverse Impulse Purging Valve 3 by transfer hose 2.

With reference to Drawing No. 1, the Reverse Impulse Purging Valve mechanism contains an inlet chamber 1 main valve 16 and seat 14 to prevent compressed mains pressure air from entering the suction line via the vacuum chamber 20 before the pre-set level of vacuum has been reached. Also contained within the inlet chamber is a port which enables 25 compressed air to occupy accumulator 3 via transfer hose 13.

Firmly affixed to the main valve seat is a vacuum chamber 20 that is completely open to the suction line. Annexed to the vacuum chamber 20 is a diaphragm housing 4 incorporating diaphragm 8 high pressure seals 12 valve spools rod 9 main return spring 11 spring tensioner 6. With push rod 7 located on opposite side of the diaphragm 8 in the vacuum chamber The purpose of the vacuum chamber 20 is to contain and monitor vacuum within the suction line. The purpose of the diaphragm housing 4 is threefold: 1. To seal vacuum housing 2. Direct and regulate a charge of air from accumulator 3 at pre set level.

3. Maintain duration and rate of return through airbleed off through port 23.

Operating Cycle Refer to Drawing No I Stage 1. Shows Reverse impulse Purging Valve in its 'at rest' position. Not being influenced by air pressure or vacuum at this stage with mains pressure air supplied to accumulator 3 from inlet chamber 1 via transfer hose 13."Further air is prevented from entering vacuum chamber 20 by main valve 16. Accumulator 3 contains a charge of air at mains pressure, less check valve 15 pre-set pressure. The charge contained in accumulator 3 is prevented from escaping into diaphragm housing 4 via transfer hose by valve spool rod 9. Mains pressure air represented by orange shading.

Drawing No 2 Stage 2 shows the typical condition of Reverse Impulse Purging Valve with pumping system running normally. Fluid under vacuum represented by green shading occupies the volume so indicated. As system continues to run normally, so too does Reverse Impulse Purging Valve remain in this position. Small fluctuations are checked by main return spring 11. Advancement of push rod 7 is permitted without influence upon main valve 16 because of free movement of valve extension spring 15 Drawing No 3 Stage 3 shows Reverse Impulse Purging Valve at the point where material has blocked the system's filter/strainer sufficiently to cause an increase of vacuum within suction line. The increased vacuum and subsequent force supplied to the diaphragm 8 has overcome spring 11 tension and pre-set load supplied by adjusting knob 6.

2Transfer port in valve spool rod 9 has now entered high pressure seal pack 12. High S 20 pressure air is admitted to diaphragm housing cavity 4 via transfer port in valve spool rod 9 from accumulator 3 and transfer hose. At this stage valve extension spring 10 is fully compressed, and main valve 16 is at crack point. In this position the main valve 16 is committed to open.

Drawing No 4 Stage 4 shows diaphragm 8 under influence of full pressure/volume of air 25 from accumulator 3. The subsequent force supplied to diaphragm 8 has progressed push rod 7 to its limit. Valve extension spring 10 has regained half of its compressed length and has increased the effective length of push rod 7. Opposed only by the smaller force supplied by valve return spring As main valve 16 remains open so too is mains pressure/volume air admitted directly from mains supply via transfer ports 2 into vacuum chamber/suction line 20. The substantial increase in pressure and flow forces fluid in the suction line back through strainer/filter and the ensuing column of high pressure/volume air percolates through filter/strainer removing all obstacles.

The duration of purge of high pressure/volume air is dictated by the time it takes to evacuate the charge of air contained in accumulator 3, transfer hose and diaphragm cavity 4, through bleed port 23.

3 The afore mentioned increase in effective length of push rod 7 allows transfer port 9 to escape high pressure seals 12 under force supplied by main return spring 11, before main valve 16 closes. Thus allowing main return spring 11 to return fully to original position shown in Drawing 1 Stage 1. The cycle is ready to begin again.

Refer to Drawing 1 Stage 1. This device can be manually operated by applying a force to adjusting knob 6 sufficient to overcome main return spring 11 tension. At this point the spring tension is overcome by a charge of air from accumulator 3 and is thereafter power operated for one complete cycle.

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Claims

1. A purging valve to clear pumping systems suction lines and strainers of material that would otherwise form a blockage.Consisting of a diaphram and its spring opposition to monitor the extent of vacuum within said suction line and connected to a main valve to controll the flow of higher pressure fluid as the cleaning medium.Activated at a given point with respect to the suction increase,and selected by setting the tension on return spring to correspond with the force on diaphram due to vacuum.

2. The purging valve of claim 1 wherein all embodiments may be wholly contained within the one assembly or individually located adjacent to each other upon the suction line. S

3. The purging valve of claim 1 wherein the said diaphram is 15 replaced by a piston and cylinder to perform the same function. o

4. The purging valve of claims 1-3 may be included as an integral S* part of a pump or strainer assembly as an added fixed or accessory feature for that item. JOHN THOMAS BEER 30 may 1999 JOHN THOMAS BEER 30 may 1999