GB1598068A - Direct gas pressure liquid pump - Google Patents

Description

(54) DIRECT GAS PRESSURE LIQUID PUMP (71) We NORMAN RICHARD WATSON, of Glenholm, Lancaster Road, Claughtonon-Brock, in the County of Lancaster, a British subject, and SAMUEL JOHN HODGKIsS, of The Cottage, 28 Kinnersley, Severn Stoke, Near Worcester, in the County of Worcester, formerly of Higher Close Farm, Withnell, Chorley, in the County of Lancaster, a British subject, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to pumps and more particularly to a pump which is adapted to be at least partially immersed in the fluid which is to pumped thereby.

According to this invention, a pump for pumping a fluid comprises a chamber which is adapted to be at least partially immersed in the fluid, having an inlet aperture formed in the wall of the chamber to allow the fluid to enter the chamber, an outlet pipe extending from the lower portion of the chamber through which the fluid in the chamber is discharged, and an inlet pipe connected to the upper portion of the chamber through which a gas under pressure is supplied to the chamber, wherein closure means comprising a flap is provided for closing the inlet aperture when the gas under pressure is supplied to the chamber, the flap being pivotally connected to a point on the chamber spaced apart from the edge of the inlet aperture so that the flap is pivotally movable from a closed position in which the flap covers the inlet aperture to an open position in which at least part of the inlet aperture is uncovered, and during pivotal movement of the flap from the closed to the open position, the portion of the flap adjacent to the pivotal connection thereof to the chamber moves inwardly of the chamber away from the edge of the inlet aperture.

Preferably, valve means is provided in the inlet pipe which is adapted to selectively enable the gas under pressure passing therethrough to be diverted to atmosphere thereby causing the pressure in the chamber to be reduced to a minimum, thus allowing the chamber to be substantially filled with the fluid prior to reintroduction of the gas under pressure thereto.

Preferably, also, control means is provided for controlling the operation of the valve means so that the valve means diverts the gas blowing through the inlet pipe to atmosphere for a predetermined period of time which is sufficient for the chamber to substantially fill with fluid.

The control means, preferably, comprises a pressure sensing device for sensing the pressure in the chamber and timer means brought into operation by signals from the pressure sensing device.

A preferred embodiment of this invention will now be described, by way of example only, with reference to the accompanying drawings of which: Figure 1 is a perspective view of a pump mounted in a slurry tank; Figure 2 is an electrical circuit diagram of a control means for the pump; and Figure 3 is a sectional side elevation of a modified pump.

Referring now to Figure 1 and Figure 2 of the drawings, a pump indicated generally at 10 for pumping slurry is shown positioned in a settling tank or reception pit 12. The pump 10 is immersed in the slurry and, in this particular example, is utilized for pumping slurry from the settling tank or reception pit 12 into a main slurry tank (not shown).

The pump 10 comprises a chamber 14 mounted in the tank or pit 12 below the level of the slurry and the chamber 14 has a rectangular inlet aperture 16 formed in one side face thereof. A flap 18 is pivotally connected along its upper edge to an upper edge 20 of the inlet aperture 16 and is pivotally movable inwardly of the chamber from a "closed" position in which the flap 18 extends over the entire area of the aperture and closes said aperture, to an "open" position shown in broken lines in Figure 1 of the drawings, in which the inlet aperture 16 is at least partially open to allow the slurry to flow from the tank or pit 12 into the chamber 14.

An outlet pipe 22 is connected at one end to the lower portion of the chamber 14 and at the other end discharges into the main slurry tank (not shown). An inlet pipe 24 is connected to the upper portion of the chamber 14, and air under pressure is supplied through the inlet pipe 24 from a compressor (not shown) to the chamber 14. An electrically-operated valve 26 is mounted in the inlet pipe 24 at a point above the level of the slurry, and the valve 26 is adapted to selectively direct the air flowing therethrough direct to atmosphere when the valve 26 is actuated.

A pressure switch 28 is shown mounted in a convenient position in the portion of the inlet pipe 25 between the valve 26 and the chamber 14 for sensing the pressure in the chamber 14, but it will be appreciated that the pressure switch 28 can be mounted at any point in the inlet pipe 24 downstream from the valve 26 or in the chamber 14 itself.

An electrical control system indicated generally at 30 in Figure 2 of the drawings is provided for controlling the operation of the valve 26 and the system 30 includes a normally closed contact 32 of the pressure switch 28 which is connected at one side to a live terminal 34 of a conventional alternating current electrical supply.

The other side of the contact 32 is connected to one side of a first relay coil 36 and the other side of the coil 36 is connected to a neutral terminal 38 of the alternating current supply. The pressure switch contact 32 is also connected via a resistor 40 and a diode 42 to a second relay coil 44 and the other side of the coil 44 is connected via a large capacitor 46 of, for example, 200 micro-farad capacitance to the neutral terminal 38 and also via a normally closed contact 48 of the first relay 36 and a resistor 50 to the neutral terminal 38. A small smoothing capacitor 52 of, for example, 0.5 micro-farad capacitance, is connected in parallel with the second relay coil 44 to provide smoothing of the current supplied through the diode 42 to the coil 44.

The pressure switch contact 32 is also connected via a normally open contact 54 of the second relay 44. to one side of a coil 56 of the electrically operated valve 26 and the other side of the coil 56 is connected directly to the neutral terminal 38. When the coil 56 is energised, the valve 26 is opened and allows the air under pressure supplied from the compressor (not shown) through the inlet pipe 24 to pass directly to atmosphere.

When the pump 10 is brought into operation and the electrical supply connected, the contact 32 of the pressure switch 26 is closed, as the chamber 14 and the inlet pipe 24 are not pressurised. The flap 18 is moved to the "open" position by the force exerted thereon by the slurry in the tank or pit 12 and the slurry flows into the chamber 14 through the inlet aperture 16 to fill the chamber 14.

An electrical current is supplied through the closed pressure switch contact 32 to the first relay coil 36 which is thus energised causing the normally closed contact 48 thereof to open. Electrical current is also supplied through the pressure switch contact 32 via the resistor 40 and the diode 42 to the second relay coil 44 and thence to the large capacitor 46 which commences to charge.

During the time required to charge the capacitor 46, the current flowing through the coil 44 energises the second relay and causes the normally open contact 54 of the second relay to close and this causes the coil 56 to energise and open the valve 26.

The air under pressure supplied through the inlet pipe 24 from the compressor (not shown) is passed directly to atmosphere and therefore does not pressurise the chamber 14.

When the capacitor 46 is fully charged after a period of, for example, fifteen seconds; the second relay coil 44 is de-energised and the contact 54 opens. This causes the coil 56 of the valve 26 to de-energise and the valve 26 closes. Air under pressure is then supplied through the inlet pipe 24 to the chamber 14 causing the flap 18 to move to the "closed" position covering the aperture 16 and the slurry in the chamber 14 is discharged through the outlet pipe 22 into the main slurry tank (not shown).

The pressurisation of the chamber 14 causes the contact 32 of the pressure switch 28 to open and the supply of electrical current to the coil 36 of the first relay is removed thus de-energising the first relay and causing the contact 48 thereof to close.

The closing of the contact 48 discharges the capacitor 46 through the resistor 50 leaving it ready to be charged again during the next cycle of operation.

The slurry is discharged from the chamber 14 until the level thereof falls below the level of the outlet pipe 22 and when this stage is reached, the air under pressure in the chamber 14 flows freely through the pipe 22. The pressure in the chamber 14 falls and the contact 32 of the pressure switch 28 closes and the cycle of operation described above is repeated.

It will be appreciated that during the time required to charge the capacitor 46 in the next cycle of operation, the chamber 14 is filled with slurry from the tank or pit 12 and if this period of time is not of sufficient duration to allow the chamber 14 to completely fill with slurry, it can be increased by introducing a new capacitor of larger capacitance than the capacitor 46.

Referring now to Figure 3 of the drawings, in a modification of the pump 10, the flap 18 is provided at its upper edge with an extension piece 60 which is pivotally connected to a lug 62 mounted in the chamber 15 at a point spaced above the upper edge of the inlet aperture 16. The pivotal axis of the flap 18 is thus spaced above the upper edge of the inlet aperture 16 and then the flap 18 moves to the "open" position shown in broken lines in Figure 3 of the drawings, the upper portion of the flap 18 moves inwardly of the chamber 14 away from the upper edge of the inlet aperture 16 so that the flow of slurry through the inlet aperture 16 is not restricted by the flap 18.

In a further modification, the valve 26 and the control system 30 are dispensed with and the pump 10 carries out the above described filling and pumping cycles with a frequency which is determined by the natural frequency thereof. It will be appreciated that this natural frequency of operation may not allow sufficient time for the chamber of the pump to be completely filled with slurry before pumping recommences due to the increase in pressure in the chamber which occurs when the incoming slurry covers the outlet pipe and it is therefore advantageous to provide the pump with the above control system.

WHAT WE CLAIM IS: 1. A pump for pumping a fluid comprising a chamber, which is adapted to be at least partially immersed in the fluid, having an inlet aperture formed in the wall of the chamber to allow the fluid to enter the chamber, an outlet pipe extending from the lower portion of the chamber through which the fluid in the chamber is discharged, and an inlet pipe connected to the upper portion of the chamber through which a gas under pressure is supplied to the chamber, wherein closure means comprising a flap is provided for closing the inlet aperture when the gas under pressure is supplied to the chamber, the flap being pivotally connected to a point on the chamber spaced apart from the edge of the inlet aperture so that the flap is pivotally movable from a closed position in which the flap covers the inlet aperture to an open position in which at least part of the inlet aperture is uncovered. and during pivotal movement of the flap from the closed to the open position, the portion of the flap adjacent to the pivotal connection thereof to the chamber moves inwardly of the chamber away from the edge of the inlet aperture.

2. A pump according to Claim 1, wherein valve means is provided in the inlet pipe which is adapted to selectively enable the gas under pressure passing therethrough to be diverted to atmosphere thereby causing the pressure in the chamber to be reduced to a minimum, thus allowing the chamber to be substantially filled with the fluid prior to reintroduction of the gas under pressure thereto.

3. A pump according to Claim 2, wherein control means is provided for controlling the operation of the valve means so that the valve means diverts the gas flowing through the inlet pipe to atmosphere for a predetermined period of time which is insufficient for the chamber to substantially fill with fluid.

4. A pump according to Claim 3, wherein the control means comprises a pressure sensing device for sensing the pressure in the chamber and timer means brought into operation by signals from the pressure sensing device.

5. A pump constructed, arranged and adapted to operate substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. inlet aperture 16. The pivotal axis of the flap 18 is thus spaced above the upper edge of the inlet aperture 16 and then the flap 18 moves to the "open" position shown in broken lines in Figure 3 of the drawings, the upper portion of the flap 18 moves inwardly of the chamber 14 away from the upper edge of the inlet aperture 16 so that the flow of slurry through the inlet aperture 16 is not restricted by the flap 18. In a further modification, the valve 26 and the control system 30 are dispensed with and the pump 10 carries out the above described filling and pumping cycles with a frequency which is determined by the natural frequency thereof. It will be appreciated that this natural frequency of operation may not allow sufficient time for the chamber of the pump to be completely filled with slurry before pumping recommences due to the increase in pressure in the chamber which occurs when the incoming slurry covers the outlet pipe and it is therefore advantageous to provide the pump with the above control system. WHAT WE CLAIM IS:

1. A pump for pumping a fluid comprising a chamber, which is adapted to be at least partially immersed in the fluid, having an inlet aperture formed in the wall of the chamber to allow the fluid to enter the chamber, an outlet pipe extending from the lower portion of the chamber through which the fluid in the chamber is discharged, and an inlet pipe connected to the upper portion of the chamber through which a gas under pressure is supplied to the chamber, wherein closure means comprising a flap is provided for closing the inlet aperture when the gas under pressure is supplied to the chamber, the flap being pivotally connected to a point on the chamber spaced apart from the edge of the inlet aperture so that the flap is pivotally movable from a closed position in which the flap covers the inlet aperture to an open position in which at least part of the inlet aperture is uncovered. and during pivotal movement of the flap from the closed to the open position, the portion of the flap adjacent to the pivotal connection thereof to the chamber moves inwardly of the chamber away from the edge of the inlet aperture.

2. A pump according to Claim 1, wherein valve means is provided in the inlet pipe which is adapted to selectively enable the gas under pressure passing therethrough to be diverted to atmosphere thereby causing the pressure in the chamber to be reduced to a minimum, thus allowing the chamber to be substantially filled with the fluid prior to reintroduction of the gas under pressure thereto.

3. A pump according to Claim 2, wherein control means is provided for controlling the operation of the valve means so that the valve means diverts the gas flowing through the inlet pipe to atmosphere for a predetermined period of time which is insufficient for the chamber to substantially fill with fluid.

4. A pump according to Claim 3, wherein the control means comprises a pressure sensing device for sensing the pressure in the chamber and timer means brought into operation by signals from the pressure sensing device.

5. A pump constructed, arranged and adapted to operate substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.