US2357434A - Expansible chamber pump - Google Patents

Description

Sept. 5, 1944. D. TAYLOR EXPANSIBLE CHAMBER PUMP Filed Oct. 9, 1942 N YEN TOR jazylad TZ'ZZOW ATTORNEYS.

Patented Sept. 5, 1944 UNITED STATES? PATENT OFFICE EXPANSIBLE CHAMBER PUMP Douglas Taylorfolihull, England Application October 9, 1942, Serial No. 461,440 In Great Britain November 28, 1941 11 Claims 1C1. 103-1) This Invention relates to expansible chamber pump. In certain grinding machines, a mixture of oil and grinding powder suspended therein is continuously circulated between a sump and the work. The grinding powder settles in the sump and difficulty has been experienced in maintaining a circulation of oil and grinding powder of the required consistency. Heretofore, a rotary pump has been utilised for circulating the mixture and it is found that the pump rapidly wears;

away by the grinding action of the mixture passing through the pump and moreover the grinding powder settles in the tank and is not circulated.

By the present invention, an appliance is provided for circulating the mixture of liquid and. suspended grinding material which maintains a circulation of mixture of the required consistency. By this invention also sliding parts in contact with the grinding mixture are also avoided.

According to the present invention, means for lifting or pumping a mixture of liquid with a solid suspended therein comprises a pump cylinder or container and a lifting piston or member which lifts the mixture and is mounted in such-- a manner that bearing surfaces are not in contact with the mixture- The means may comprise a pump cylinder, a piston mounted to reciprocate therein with the wall of the piston spaced from the wall of the cylinder, a piston rod:

carrying the piston and mounted in a guide above the level to which the mixture is raised, and means for reciprocating the piston on the lifting stroke quicker than on the return stroke so that a volume of mixture is raised and so that:

the mixture is displaced between the piston and the wall of the cylinder to permit the movement of the piston on the return stroke. The piston is conveniently raised by power and moved on the return stroke by gravity. The pump piston may be raised by compressed air or fluid which is admitted to a cylinder to drive a power piston to raise the pump piston and released from the cylinder to permit the lifting piston to fall by gravity or spring pressure, and the fluid is raised to a higher level than a discharge outlet to maintain a continuous flow through such discharge outlet. A surplus of fluid is preferably raised and means are provided to return the surplus fiuid to the sump feeding the pump. The control of the fluid to the power cylinder is effected by the piston or part moving therewith. The sump feeding the pump cylinder may have an inclined bottom from the lowest part of which the mixture is drawn into the pump and the overflow is directed to enter the sump above the bottom at the highest level and to assist the flow of any deposit towards the part feeding the pump.

In order that the invention may be clearly understood and readily carried into effect, reference may be had to the accompanying draw-'- ing, on which- Figure 1 is a sectional elevation of a device constructed according to this invention.

Figure 2 is a side elevation of the upper por tion of the device shown by Figure 1.

Figure 3 is a section on line III-III of Figure 1.

Figure 4 is a section of the valve, hereinafter referred to, and g a Figure 5 illustrates a side elevation showing a modified form of the invention.

According to a convenient embodiment, the invention is applied to a grinding machine for circulating grinding material suspended in oil between a sump and the work or grinding operation. The apparatus comprises a cylinder or tube I which is mounted on a base plate 2. An inlet opening is formed in the base plate and is normally closed by means of a non-return valve comprising a heavy steel ball 3 which may be for instance, 2 in diameter. A piston or lifter 4 is mounted in the piston cylinder and the pistonrod 5 is extended upwardly and is reduced in diameter at 5a and passes through a a packing gland 6 into a compressed air cylinder I. A piston 8 on the rod 5a is mounted to reciprocate in the compressed air cylinder 1 and is adapted to be lifted by compressed air and to move on its return stroke by gravity and so that the piston 4 has a quick lifting stroke and a slow return. In a preferred form, air enters into the cylinder 1 on the underside of the piston by way of the conduit H and the annular space around the outside edge of the valve disc l2. The air is exhausted by way of a series of holes VI 3 in the boss M, the holes being normally closed by the valve disc I2. The valve disc 12 comprises a metal disc having a rubber seating ring 14 moulded preferably on each face, the two rings being connected by rubber studs l5 passing through holes in the disc so that the seating rings are securely fixed to the metal disc. When one seating wears, the disc can bereversed. The valve disclZ is normally held on its seating by the pressure of air in the cylinder 1. When the piston 8 is at the top of its stroke, the shoulder I6 moves against the disc l2 and raises the same from its seating thereby allowing the air to exhaust. The inlet II is continuously feeding air to the cylinder 1 but the air is exholds the valve on its seating and again raises the piston 8. The lifter piston 4 therefore is raised quickly on the pumping stroke, whilst this piston 4 is free to fall through the liquid on the return stroke, the rate of drop being determined by the weight or pressure on the piston 4 and the rate of flow of the liquid passed the piston. An air release opening is formed in the cylinder wall. The pumping piston 4 and rod 5 are comparatively heavy, so that there is sufficient force of gravity to cause the same to fall through the mixture in the cylinder I, consequently moving the compressed air piston on its return stroke. The piston 4 in the pumping cylinder may be a solid piston or may be formed of a number of piston discs 4a mounted on the piston rod, and forming annular grooves to give a number of lifting surfaces 42) on the upper side and conical faces on the lower side to facilitate travel through the liquid. The upper end of the pump cylinder has an overflow outlet 9 and at a lower position a discharge outlet III which may be a conduit delivering the mixture of oil and grinding material by gravity to the grinding operation such as that of grinding cylinders of internal combustion engines. As the base of the pump cylinder is fitted with non-return ball valve 3 liquid will always be maintained in the pump cylinder to the level of the discharge outlet Ill. The pumping piston 4 is constantly immersed in the liquid and is of smaller diameter than the bore of the cylinder I. When the piston 4 is lifted at the required speed by compressed air fed into the compressed air cylinder, the piston will be lifted at a rate which will not permit the liquid to flow past the piston from the top to the underside at a rate which will prevent liquid being lifted. Suction is thus created which draws the mixture of oil and grinding material from the sump through the non-return valve 3. The amount of liquid raised fills the cylinder above the discharge outlet I0 and the rate of reciprocation is such that the liquid is not permitted to fall to the level of such outlet, thereby obtaining a reserve supply and maintaining a constant rate of flow through the discharge outlet Ill. The rate of pumping is also preferably such that a quantity overflows through the overflow opening 9 back to the sump. This maintains the mixture in the sump and in the pump cylinder in a state of agitation and assists in maintaining circulation to the V grinding operation of mixture of the required consistency. The movement of the piston in the cylinder will agitate the oil therein. The position of the packing gland 6 at the base of the air cylinder in relation to the said overflow outlet 9 is such that part of the piston rod reciprocating through the gland does not dip into the mixture of oil and grinding powder. The overflow through the opening 9 is conveniently collected in an annular chamber I8 surrounding the cylinder and the liquid conducted back to the sump I9 by way of the two pipes 20. The

Sump I9 has an inclined bottom and the inner end of the sump under the inlet opening controlled by the valve 3 is partitioned oif by the wall 22. Should, therefore, solid tend to settle it will flow down to the bottom of the tank and will be sucked up into the cylinder I. The partition 22 extends to a short distance from the bottom of the tank, and therefore, the mixture is sucked up into the cylinder I from the lowest point of the tank. The ends of the pipes 29 are arranged to direct the flow down the inclined bottom and this will assist in causing the return mixture from the work to flow to the lowest part of the sump. When the apparatus is delivering a mixture of grinding material suspended in oil, the grinding powder would settle in a solid mass if the circulation ceased for any length of time; by closing the flow from the outlet II] the circulation through the cylinder I and back to the sump can be continuously maintained thereby keeping the mixture in a constant state of agitation. The mixture supplied to the work is returned to the sump I 9 by way of suitable chutes or conduits 29. By the use of the overflow circulation it is ensued that grinding powder or solid matter will be intimately mixed with the liquid and mixture of uniform consistency will be delivered through the conduit I0.

In a further form of the invention,.the mixture delivered by the pump passes to the "work through the intermediary of a settling tank for the purpose of obtaining a thickened mixture containing a higher percentage of solid matter for delivery of the work or grinding operation. In one form the delivery opening 23 from the pump cylinder Ia feeds the mixture into' a tank 24 having an inclined bottom25, a partition plate 26 divides the tank so that the mixture can only flow downwardly on the underside of the'partition 26 and upwardly in the space on the upper side of this partition. A delivery outlet 21 is provided down the lowest point of the tank at the end of'the inclined bottom whilst an overflow outlet or outlets 28 at the top of the tank return the surplus back to the sump from which the mixture is pumped into the cylinder Ia. The solid matter will settle to the bottom of the tank and will be delivered through the feed outlet 21 so that the mixture delivered therethrough will have -a greater solid content than the mixture passing through the overflow back to the sump. Any matter settling on the inclined bottom will flow to the outlet 21.

If the mixture reaches sliding parts, the sliding faces would be subjected to a grinding action and wear would be very rapid, but with the aforedescribed construction, the mixture of oil and grinding powder does not contact with any sliding parts. Again the heavy ball closing the inlet to the pump cylinder ensures an efiicient non-return closure and again there are no sliding parts. The invention may be applied to any lifting or pumping apparatus for dealing with any mixture of liquid and solid suspended therein.

In lieu of the pumping piston being operated by air pressure it may be operated electrically such as by a solenoid or again mechanical means may be used for this purpose.

I claim:

1. Means for lifting or pumping a liquid having a solid suspended therein around a continuously circulating system comprising a pump cylinder, a piston mounted to reciprocate therein and spaced from the wall of the cylinder, power 2. Means for lifting or pumping a liquid with "a solid suspended therein comprising a pump cylinder, a piston mounted to reciprocate therein without contacting with the wall of the cylinder, means for lifting the piston to raise the liquid .in the pump cylinder, a non-return valve through which the liquid is drawn by the piston, a sump from which the liquid is pumped, an outlet from the pump cylinder at a height below that to which the liquid is raised by the piston and through which the liquid is discharged by gravity, and another discharge outlet above the first mentioned outlet through which surplus liquid raised by the pump is returned back to the sump to maintain the liquid in the sump and pump cylinder in a state of agitation.

3. Means for lifting or pumping a liquid comprising a pump cylinder, a piston and a piston rod mounted to reciprocate therein and spaced from the wall of the cylinder, means for lifting the piston to raise the liquid in the pump cylinder, a non-return valve through which liquid is drawn from a source of supply by the piston on th lifting stroke, a compressed air piston mounted on an extension of the pump piston rod, a compressed air cylinder in which the compressed air piston reciprocates, means for admitting compressed air to move the air piston to raise the pump piston, and automatic means for releasing the air at the end of the power stroke to permit the pump piston to move downwardly through the liquid in the pump cylinder independently of the compressed air pressure.

4. Means for lifting or pumping a liquid having a solid suspended therein, comprising a pump cylinder, a piston mounted to reciprocate therein and spaced from the wall of the cylinder, power mean for moving the piston on the pumping stroke, a sump for feeding the pump, a non-return valve through which the liquid passes from the sump to the pump cylinder, and means for discharging a surplus of liquid raised by the pump back to the said sump to keep the liquid in th sump and pump cylinder in a state of agitation, an inclined bottom on the said sump leading to the lowest part of the sump from which the mixture is drawn into the pump, and

means for delivering the said surplus liquid to the sump so that it is directed to flow downwardly over the inclined bottom of the sump.

5. Means for lifting or pumping a liquid, comprising a vertically arranged pump chamber and a piston and piston rod mounted to reciprocate in the chamber and lift the liquid in the pump chamber and arranged so that the piston is distanced from the wall of the pump chamber, an outlet for the liquid in the pump chamber and guide means for the piston rod above the said outlet so that the liquid does not contact with the guide means and the portion of the piston rod sliding therein.

6. Means for lifting or pumping a liquid. comprising a vertically arranged pump cylinder, a piston mounted to reciprocate therein and spaced from the wall of the cylinder, a piston rod carryin the piston on the lower end, means connecting to the piston rod for lifting the piston to lift the liquid in the pump cylinder at 'a quicker 'rate than it 'canflow back around the piston, a ndmretum valve through which liquid is drawn from a source of supply by the piston on the lifting stroke, and an outlet fromthe pump cylinder through which liquid is discharged, and means whereby the liquid will continu to discharge on the return stroke of the piston.

7. Means for lifting or pumping a liquid, comprising a vertically arranged pump cylinder, a piston and piston rod mounted to reciprocate therein with the piston spaced from the wall of the cylinder, means connected to the upper end of the rod of said piston for lifting the piston by power to raise the column of liquid in the pump cylinder, a non-return valve through which liquid is drawn from a source of supply by the piston on the lifting stroke, guide means for the piston rod which does not contact with the liquid pumped and means for cutting out the power drive on the return stroke to permit the return of the pump piston.

8. Means for lifting or pumping a liquid comprising a vertically arranged pump cylinder, a piston and a piston rod mounted to reciprocate therein with the piston spaced from the wall of the cylinder, a non-return valve at the bottom of the cylinder through which liquid is drawn from a source of supply by the piston on the lifting stroke, a compressed air cylinder mounted on the upper end of the pump cylinder, an extension of the piston rod, guide means for the piston rod which does not contact with the liquid pumped, a piston operated on by compressed air mounted on such extension, an inlet for continuously supplying compressed air to the air cylinder, an air exhaust port, a valve normally closing the exhaust port, means for opening the valve at the end of the power stroke of the air piston to permit the pump piston to fall by gravity on the return stroke, and means for closing the valve at the end of the return stroke of the air piston.

9. Means for lifting or pumping a liquid comprising a vertically arranged pump cylinder, a piston rod and a piston having a number of annular grooves each forming a flat lifting face to facilitate lifting the liquid and an inclined face to facilitate the travel of the piston through the liquid on the return or downward stroke and mounted to reciprocate in the cylinder and distanced from the wall of the cylinder by an annular space, means connected to the upper end of the piston rod for lifting the piston to raise the liquid in the pump cylinder, which means leaves the piston free to return at the end of the lifting stroke at a slower rate than the lifting stroke so that the liquid can flow in the annular space between the piston and the wall of the cylinder, guide means for the piston rod which does not contact with the liquid'pumped, a non-return valve through which liquid is drawn from a source of supply at the bottom of the pump cylinder by the piston on the lifting stroke, and a delivery outlet from the pump cylinder below th level to which the liquid is raised in such cylinder to obtain a delivery from the pump cylinder during the return or nonworking stroke of the pump piston.

10. Means for lifting or pumping a liquid with a solid suspended therein comprising a pump cylinder, a piston mounted to reciprocate therein and spaced from the wall of the cylinder and mounted so that it is free to move down- Wards on the return or non-power stroke, means for lifting the piston to raise the liquid in the pump cylinder which means leave the piston free to return at the end of the lifting stroke so that it is free to move downwards on the return or non-power stroke, a non-return valve through which liquid is drawn from a source of supply by the piston on the lifting stroke, a discharge outlet in the pump cylinder, a. settling tank receiving the discharge from the outlet and having an inclined bottom, an outlet from the lowest point of the tank for delivering liquid and solid and an overflow outlet at the top of the tank for returning liquid direct to the source of supply.

11. Means for lifting or pumping a liquid, comprisin a vertically arranged pump chamber and a piston and piston rod mounted to reciprocate in the chamber and lift the liquid in the pump chamber and arranged sothat the piston is distanced from the wall of the pump chamber, an outlet for the liquid in the pump chamber, a non-return valve at the base of the cylinder through which the liquid is drawn into the pump chamber and guide means for the piston rod above the said outlet so that the liquid does not contact with the guide means and the portion of the piston rod sliding therein.

DOUGLAS TAYLOR.

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