GB2267315A - Air/stream operated fluid pumps - Google Patents

Abstract

An air or steam driven venturi 3 creates suction in chamber 1 so that liquid (or semi-liquid) to be pumped enters at check valve 8. As the liquid level rises, float 5 rises to close slide valve 4 and pressurised air or steam then acts on the surface of the liquid to elect it through check valve 9 into liquid outlet 11. Liquid is dispensed until the falling float 5 acts on valve 4 to again allow the venturi to operate. The air or steam flow through the venturi is routed through tube 12 into the liquid outlet 11. <IMAGE>

Description

AIR/STEAM OPERATED FLUID PUMPS FIELD This invention relates to a pump for liquids or semiliquids of the air operated type in which the depression for lifting or drawing the liquid into the body of the pump is achieved by air under pressure passing through a venturi and the discharge by pressurising the container from the same supply of air by closing off the outlet from the venturi; this changes the depression in the pump body to pressure, thus closing the inlet swing valve and opening the outlet swing valve and discharging the liquid from the pump body. The closing of the venturi outlet is brought abouut by having a float in the pump body connected through a system of levers to a control valve.

HISTORY In this field it is already known to/that in such pumps, at present, air is exhausted to atmosphere creating considerable noise, despite the fitting of mufflers, and under certain atmospheric conditions freezing occurs in the outlet because of the rapid expansion of the air being exhausted, reducing the efficiency of the pump or even causing it to cease operating completely till thawed out.

There are other features in this system having considerable adverse effects environmentally and in the safety aspect.

These are caused by the fact that, during operation, as the venturi is, of necessity, mounted within the pump body, carry over of the liquid occurs along with possibly noxious or inflammable vapours. These are discharged into the atmosphere, resulting in at least a mess and at worst a potential health and fire hazard. Similarily, should the pump be inadvertently disturbed from its normal vertical position, the liquid and gases can be forced out of the exhaust with similar consequences to those of the carry over described above.

According to the present invention there is provided a pump system for delivering a first fluid, the system having an inlet and an outlet for the first fluid, and pump means operated by a second fluid for moving the first fluid from said inlet to said outlet, the exhaust of said pump means being selectibly connectable to said system outlet to couple the exhausted second fluid from the pump means to said outlet.

Preferably said first fluid is a liquid or semi-liquid, the pump means is operated by the pressure or the flow of the second fluid in the pump means.

Typically, the pump means may be a venturi operated pump mechanism and preferably the pump system operates by sucking a volume of liquid through the inlet into a chamber and subsequently expelling the fluid from the chamber through the outlet.

Preferably, the exhaust includes a valve mechanism to prevent the backflow of the fluid being pumped or the second fluid from the said outlet through said exhaust to the pump means.

DESCRIPTION To accomplish this a pump of the type described has the air exhausted through a swing check valve and directed into the pump discharge outwith the discharge check valve.

An example of the invention is now described with reference to the accompanying drawing which shows a fragmentary sectional side view of a pump incorporating the invention.

A pump consists generally of a cylinder (1) with a casting at the top (2) incorporating a venturi (3) and control valve (4) is connected to a float (5) through a system of arms (6). IVhen the float (5) reaches the top position, it closes the control valve (4), thus stopping the flow of air through the venturi so that the environment in the pump cylinder is changed from depression to compression.

The casting (7) at the bottom of the pump incorporates an inlet swing valve (8) and an outlet swing valve (9). Once the control valve (4) has closed the pressure in the pump cylinder closes the inlet swing valve (8) and opens the outlet swing valve (9) and forces the liquid out of the pump cylinder (1) into the following pipework. As the liquid is evacuated, the float (5) drops and as it approaches its lowest position it opens the control valve (4), again causing a depression in the pump cylinder so that the inlet swing valve (8)opens, the outlet swing valve (9) closes and liquid is sucked into the pump cylinder.

The air discharging from the venturi passes through a swing check valve (10) and thence into the subsequent pipework, forcing the liquid which has just passed from the pump cylinder (1) along, the pipework, expanding gradually as it does so and drawing the necessary heat for expansion from the liquid or pipework, thus obviating the possibility of freezing. The swing check valve (10) is necessary to prevent the possibility of liquid entering the contol valve (4) during discharge.

ADVANTAGES This invention immediately reduces the noise level from 117 decibels to 78 decibels. It also eliminates freezing because the air cannot now expand rapidly enough to cause freezing and the other above mentioned problems are completely eliminated because the system is now a sealed unit.

An added advantage is that whilst sucking, this discharged air introduced into the discharge line purges this line resluting in a faster emptying cycle, thus improving the pump's efficiency.

This type of pump is used extensively in offshore applications because of its reliability and tolerance of foreign bodies, mainly for transfer of drilling muds and similar liquids.

However, in oil spillage operations necessitating the use of a manually held suction head to clean up an area, this type is rejected because of noise and the carry over of the oil basted mud defeating the object of the exercise and a double diaphragm type pump is used instead.

With those problems eliminated, one pump can thus be used for both operations and this also removes the dis-advantage inherent in diaphragm pumps of burst diaphragms due to foreign bodies, when the liquilsludge can then pass through the diaphragm into the air stream and thence to atmosphere, resulting in the same problems associated with the carry over previously described.

This invention results in a quieter, more efficient more reliable and environmentally friendlier pump. This invention would operate equally well with steam as a source of power and could be beneficial where heat was an advantage in transferring the liquid/sludge.

Claims (8)

1. An Air/Steam Operated Fluid Pump comprising a body, normally cylindrical for manufacturing purposes, an inlet and outlet for the first fluid, an inlet for the second fluid, normally compressed air or steam, which passes through a venturi system the exit from which is controlled by a float valve within the pump body, acted on by the first fluid level in the pump body. A swing check valve is fitted to both the inlet and outlet ports, appropriately orientated. The outlet from the second fluid exhaust is normally routed directly to atmosphere but in this case it is routed into the first fluid outlet outwith the discharge swing check valve.

2. An Air/Steam Operated Fluid Pump as claimed in Claim 1 wherein there is a swing deck valve between the second fluid exhaust and the first fluid outlet to prevent the possibility of the first fluid reaching and contaminating the float controlled valve.

3. An Air/Steam Operated Fluid Pump as claimed in Claim 1 and Claim 2 wherein the routing of the second fluid discharge into the first fluid discharge line purges the discharge line during the filling operation and thus greatly facilitates the discharge operation as the discharge line is now at least partially empty.

4. An Air/Steam Operated Fluid Pump as in Claim 3 in which the routing of the second fluid discharge into the first fluid discharge line prevents the rapid expansion of the second fluid as is the case when the second fluid is discharged to atmosphere, thus minimising the possibility of the freezing of the second fluid.

5. An Air/Steam Operated Fluid Pump as in Claim 4 in which the routing of the second fluid discharge into the first fluid discharge brings the second fluid into close contact with the first fluid and surrounding pipework, further minimising the possibility of freezing

6. An Air/Steam Operated Fluid Pump as claimed in any of the above claims in which the routing of the second fluid discharge into the first fluid discharge obviates the possibility of the contamination of the surrounding environment by inflammable or noxious fumes or the first fluid.

7. An Air/Steam Operated Fluid Pump as claimed in Claim 6 in which the routing of the second fluid discharge into the first fluid dischargereduces the noise level when operating from 117 to 78 decibels.

8. An Air/Steam Operator Fluid Pump. Substantially as described herein with reference to the accompanying drawing.