US3370759A

US3370759A - Fluid dispenser with alternate discharge floating piston

Info

Publication number: US3370759A
Application number: US512079A
Authority: US
Inventors: Johansson Gustav Adolf
Original assignee: Danfoss AS
Current assignee: Danfoss AS
Priority date: 1964-12-15
Filing date: 1965-12-07
Publication date: 1968-02-27
Anticipated expiration: 1985-02-27
Also published as: DE1217232B

Description

F 7, 1968 e. A. JOHANSSON 3,370,759 v FLUID DISPENSER WITH ALTERNATE DISCHARGE FLOATING PISTON Filed Dec. '7, 1965 3,379,759 Patented Feb. 27, 1968 3,370,759 FLUID DISPENSER WITH ALTERNATE DISCHARGE FLOATING PISTON Gustav Adolf .l'ohansson, Nordhorg, Denmark, assignor t Danfoss A/S, Nordhorg, Denmark, 2 company of Denmark Filed Dec. 7, 1965, 521'. No. 512,079 Claims priority, application Germany, Dec. 15, 1964, D 46,060 7 Claims. (Cl. 222249) ABSTRACT OF THE DISCLOSURE This apparatus comprises a double acting floating piston in a cylinder having valved inlet-outlet orifices at each end, with piston carried magnet means cyclicly controlling the operation of the inlet and outlet valves.

This invention relates to apparatus for drawing a fluid from a source of supply.

Frequently it is desired to draw a fluid from a source of supply in a plurality of predetermined uniform quantities. One example of this is the filling of refrigerant capsules for refrigerating systems and another example is the filling of aerosol containers with a propellant. In each of these instances there is a manufacturing operation involving the filling of a standard container, capsule, vessel or the like with a fluid, from a source of supply.

According to the prior art there is provided a cylinder carrying a piston, the piston being movable axially of the cylinder in both directions. The piston is operated by a power supply which is located entirely outside of the cylinder. Thus, typically, the power supply is a motor, power from which is transmitted to the piston to reciprocate the piston within the cylinder by means of a pistonshaft extending through an end wall of the cylinder and carrying the piston at its end within the cylinder, a packing being provided about the entrance of the piston shaft into the cylinder to prevent undue leakage of the fluid from the cylinder. The need for a packing is a disadvantage as this adds to the cost and complexity of the construction of the apparatus, further, because packings are never entirely satisfactory, always allowing some leakage of the fluid, and, finally, because packings wear out and require periodic replacement.

Another disadvantage of the apparatus of the prior art is that it draws oil fluid from source of supply only on every other stroke. Accordingly, this apparatus is only half as efficient as it would be if it drew fluid from the source of supply on every stroke. In the apparatus of the prior art a first stroke of the piston is required to draw fluid from the source of supply into the cylinder, during which'stroke no fluid is being forced from the cylinder to fill a container, and a second stroke to force the fluid from the cylinder to fill a container, during which second stroke the cylinder is not refilled from the source of supply. This cycle repeats and it is seen that only on every other stroke does the apparatus serve to fill a container, which is its ultimate purpose.

According to the invention there is provided an apparatus which does not have the above mentioned disadvantages of the prior art. According to the invention there is provided means defining a hollow cylindrical chamber and a piston slidably mounted in the hollow cylindrical chamber for reciprocation therein, the piston, however, not being mounted on a piston shaft. Since the piston is not mounted on a piston shaft, a piston shaft entrance and a'packing for a piston shaft entrance ar entirely obviated. A piston shaft is not used because the 7 piston is not driven by a power supply, such as a motor,

located outside of the cylinder. In fact, preferably, the mounting of the piston in the hollow cylindrical chamber simply consists in the sliding engagement of the piston with the cylindrical internal surface of the hollow cylindrical chamber, and accordingly, the piston may be referred to as being mounted to move freely along th axis of the hollow cylindrical chamber.

According to the invention, a work chamber is established in the hollow cylindrical chamber, at each side of the piston. The term work chamber indicates that each of these chambers is fully operative in contributing toward the ultimate purpose of the apparatus, i.e., the drawing of the fluid from a source of supply to fill containers. Specifically, to each of the work chambers the fluid is drawn from the source of supply and from each of the work chambers the fluid which has been drawn thereto is forced from the work chamber and accordingly may be used to fill a container.

In order that a work chamber be defined at each side of the piston to function according to the definition set forth above, there is provided an inlet conduit communicating between the source of supply of the fluid and each of the work chambers, each of these inlet conduits being provided wtih a valve, and an outlet conduit opening from each of the work chambers, each of these outlet conduits being provided with a valve. 7

To operate this apparatus the valve in the inlet conduit communicating with a first one of the work chambers is set at an open position and the valve in the inlet conduit communicating with the second work chamber is set at a closed position while, simultaneously, the valve in the outlet conduit from the first Work chamber is set at a closed position and the valve in the outlet conduit from the second work chamber is set at an open position. The pressure of the fluid at the source of supply is set to a level higher than the pressure inside the hollow cylindrical chamber. Accordingly, the fluid flows from the source of supply to the first work chamber through the inlet conduit communicating between the source of supply and the first work chamber. The fluid thus taken into the first work chamber cannot flow out therefrom since the valve in the outlet conduit opening from the first work chamber is set at a closed position. Accordingly, the fluid in the first work chamber pushes the piston to expand or enlarge the first work chamber and accordingly compress fluid in the second work chamber.

If this is the first cycle of operation before the above described operation the apparatus is initially primed by admitting a quantity of the fluid to the second work chamber; as in the case of a pump, priming need be performed only prior to the first cycle of operation. As the second work chamber is compressed the fluid contained therein is forced out of the second work chamber through the outlet conduit opening from the second work chamber. The containers to be filled may be filled directly from the outlet conduit from the second work chamber or the outlet conduit from the second work chamber may communicate with a distribution conduit from which the containers may be filled. The piston thus having completed a stroke in the hollow cylindrical chamber, the setting of each of the valves is reversed, i.e., from open to closed and from closed to open. Thus fluid from the source oi supply is drawn into the second work chamber, the piston is pushed by the fluid in the second work chamber in the direction opposite to its previous motion, the second work chamber now expanding while the first work chamber is compressed. Thus the fluid introduced into the first work chamber for the first stroke is now forced from the first work chamber through the outlet conduit therefrom and accordingly, a container may now be filled directly from the outlet conduit from the first work chamber or the outlet conduit from the first work chamber may commu- 3 nicate with a distribution conduit from which the container may be filled.

This 2-stroke cycle mayibe continuously repeated sim- ,{ply by periodically reversing the settings of all of the Wolves as above described. Thus it is seen that the apparatus of the present invention, unlike the apparatus of the ipriorart, will provide on every stroke of the piston a quantity of the fluid to be charged into the containers to beiilled.

According to a further aspect of the invention automatic setting and resetting of the valves is provided. Thus there may be provided a first sensing means disposed externally of and adjacent to the hollow cylindrical chamber and a second sensing means similarly disposed but axially spaced, with respect to the axis of the hollow cylindrical chamber, from the first sensing means. There may further be provided a signal output means mounted for movement with the piston. Conveniently the signal output means may be mounted on or in the piston. The sensing means and the signal output means are selected so that the sensing means is responsive to the output of the signal output means. Thus, for example, the signal output means may be a magnet, the output therefrom being a magnetic field, and the sensing means may be a magnetically activated switch in an electric circuit for operating the valve whereby passage of the piston carrying the magnet to a position adjacent one of the sensing means will activate the switch. Each of the sensing means is operatively connected to the valve and the response induced in the sensing means by the signal output means is employed to reverse the setting of each of the valves. The valves themselves may be solenoid valves, electric motor actuated valves, pneumatically actuated valves,

hydraulically actuated valves, or the like.

The invention is particularly convenient for drawing off a liquid from a source of supply wherein the pressure of the liquid at the source of supply is only its autogeneous pressure, i.e., its own vapor pressure. In such a system no external source of power would be required other than for the actuation of the valves. Refrigerants and aerosol propellants may conveniently be maintained in a source of supply at their autogeneous pressure. It will be appreciated from the foregoing description of the invention that in such a case the autogeneous pressure of the liquid is latent energy which is employed to drive the apparatus.

The invention will now be :further described by reference to the drawing, which is a schematic diagram of a specific embodiment of the invention.

Mounted in a hollow cylindrical chamber 1 for free sliding movement therein is a piston 2. A packing, not shown, may be provided between the piston 2 and the internal face of the cylindrical wall of the cylindrical hollow chamber 1, to provide an essentially fluid-tight seal between a first work chamber 3 defined at the left-hand side of the piston 2 and a second work chamber 4 defined at the right-hand side of the piston 2.

A storage container 5 constitutes a source of supply of the fluid, in this case a liquid refrigerant 16. A space 18 for vapor from the liquid refrigerant 16 is provided at the upper portion of the storage container 5. Accordingly, the liquid refrigerant 16 is at its autogeneous pressure in the storage container 5. A heating jacket 17 is provided about the storage container 5 to heat the liquid refrigerant 16 therein so that its autogeneous pressure is at a desired level.

The conduit 6 with its branch 6' constitutes an inlet conduit to the work chamber 3 from the storage container 5. Similarly, the conduit 6 with its branch 6 constitutes an inlet conduit to the work chamber 4 from the storage container 5. A valve 7 is provided in the inlet conduit to the work chamber 3 and a valve 8 is provided in the inlet conduit to the work chamber 4.

An outlet conduit 11', which is provided with a valve 9, communicates with the work chamber 3. Similarly, an outlet conduit 11-", which is provided with a valve 10,

communicates with the work chamber 4. Outlet conduits 11' and 11" joint a common outlet conduit 11. The common outlet conduit 11 may be provided with a valve 12. A pair of

discharge conduits

13 and 14 may communicate through the valve 12 with common outlet 11. The valve 12 has at least two positions, namely a position establishing communication between common outlet conduit 11 and discharge conduit 13 and a position establishing communication between common outlet conduit 11 and discharge conduit 14. Thevalve 12 may have a third position, namely a shut-off or completely closed position, i.e., the valve 12 may be a three-way valve and is illustrated as such in the drawing.

Mounted in the piston 2 is a magnet 19 which serves as a signal output means. Mounted outside and adjacent the hollow cylindrical chamber 3 area first sensing means 2i} and axially spaced therefrom, with respect to the axis of the hollow cylindrical chamber, a second sensing means 21. W 4

The sensing means 20 and 21 are operatively connected to the

valves

7, 8, 9, 10 and 12. As illustrated, the'valves are solenoid valves and the operative connection between the sensing means20 and 21 and the valves may constitute conventional electrical circuitry (not shown).

To initiate operation of the apparatus, the apparatus would be primed by admitting a quantity of the liquid refrigerant 16 into one of the work chambers. Thus, for example, to prime the apparatus the valves 7 and 10 are each set to a closed position'and the valve 8 is set to an open position. As a step preliminary to the entire operation the temperature of the liquid refrigerant 16 in'the storage container 5 has been setto a level at which the autogeneous pressure of the liquid refrigerant 16 'in the storage container 5 will exceed the pressure of the liquid refrigerant in either work chamber When't'he work chamber is :being compressed. Thus, a quantity of the refrigerant '16 is taken, through

conduits

6 and 6" into the work chamber 4 and by this step the apparatus has now been primed for operation. Accordingly, what will now be described applies to the continuous operation of the apparatus.

At a starting point the piston 2 is adjacent the sensing means 20. Accordingly, magnet 19 is adjacent to sensing means 20 and sensing means 20 responds by setting valves 7 and 10 to an open position,

valves

8 and 9 to a closed position and valve 12 to a position establishing communication between common outlet conduit 11 and discharge conduit 13. A refrigerant capsule 15 to be filled with the liquid refrigerant 16 is positioned at the outlet opening of discharge conduit 13 (as indicated by the arrow). The liquid refrigerant 16 is driven into the work chamber 3 and causes the Work chamber 3 to increase in size and the Work chamber 4 simultaneously to be decreased in size by pushing the piston 2 to the right of one viewing the drawing. The compression of the refrigerant in work chamber 4 :by the piston 2 drives the liquid refrigerant in the work chamber 4 out of the work chamber 4 through conduits 11", 11 and ultimately through discharge conduit 13 into the refrigerant capsule 15'which is to be filled with the liquid refrigerant 16.

When the piston 2 reaches a position adjacent the sensing means 21, as indicated by broken lines in the drawing, at which position the work chamber 4 is in a very much compressed state and the work chamber 3 is in a very much expanded state, the sensing means 21 responds to the magnet 19 by reversing the setting of each of the

valves

7, 8, 9 and 10, i.e., from open to closed and viceversa, and by changing the setting of valve 12 to establish communication between common outlet conduit 11 and discharge conduit 14 rather than discharge conduit 13. The refrigerant capsule 15 if not yet filled is moved from the outlet of discharge conduit 13 to the outlet of discharge conduit 14 or if refrigerant capsule 15 is filled a new refrigerant capsule is positioned at the outlet of discharge conduit 14. On the other hand, even if one stroke of the piston is not sufiicient to fill a capsule, the

discharge conduits

13 and 14 may be individually provided with capsules to be filled.

The liquid refrigerant 16 is drawn through

conduits

6 and 6" into the work chamber 4 and the piston 2 is pushed by the liquid refrigerant to the viewers left in the drawing with the expansion of the work chamber 4 and simultaneous compression of the work chamber 3. The compression of the work chamber 3 by the piston 2 drives the liquid refrigerant in the work chamber 3 out of the work chamber 3 through conduits 11', 11 and ultimately discharge conduit 14 from which is filled a refrigerant capsule with the liquid refrigerant. When the piston 2 in its leftward movement returns to a position at which the magnet 19 is adjacent the sensing means 20, the 2-stroke cycle is begun again and this may be allowed to repeat, continuously, as many times as desired.

The invention is not to be construed as being limited to the particular form disclosed herein, as this is merely illustrative and is not intended to limit the scope of the invention as defined in the appended claims. Thus, for example, it will be appreciated that

conduits

11, 13 and 14 and valve 12 are not necessary to the practice of the invention, for the fluid may be discharged directly from the conduits 11 and 11", these conduits not joining in a common conduit.

What I claim and desire to secure by Letters Patent is:

1. An apparatus for drawing a fluid from a source of supply, comprising means defining a hollow cylindrical chamber both ends of which are closed, a free floating piston slidably mounted in the hollow cylindrical chamher, two work chambers thus being defined, one at each side of the piston, an inlet conduit communicating between the source of supply and each of said work chambers, a valve in each of said inlet conduits, an outlet conduit opening from each of said work chambers and a valve in each of said outlet conduits, a first sensing means disposed externally on said cylinder and a second sensing means disposed externally on said cylinder, said second sensing means being axially spaced, with respect to the axis of said cylinder, from said first sensing means and signal output means comprising a magnet mounted on said piston, said first and second sensing means being responsive to the magnetic field output of said signal output means when adjacent thereto, means operatively connecting the first and second sensing means with the valves in the inlet and outlet conduits so that when the piston is adjacent to the first sensing means and said first sensing means thereby responds to the signal output means the response of said sensing means causes the valve of the inlet conduit to a first of the work chambers to be open, the valve of the inlet conduit to a second of the work chambers to be closed, the valve of the outlet conduit of the first of the work chambers to be closed and the valve of the outlet conduit of the second of the work chambers to be open and the state of each of the valves with respect to opening and closing is reversed when the piston is adjacent to the second sensing means whereby fluid is discharged from said source of supply alternately from said work chambers in selected amounts as a function of the spacing of said first and second sensing means.

2. An apparatus according to claim 1, wherein the outlet conduit from each of said chambers communicates downstream with a common outlet conduit and said common outlet conduit communicates downstream with two distribution conduits through a distribution valve having one setting communicating with a first of the distribution conduits only and another position communicating with a second of the distribution conduits only.

3. An apparatus according to claim 2, wherein there is provided means operatively connecting the first and second sensing means with the distribution valve so that when the piston is adjacent to the first sensing means and said first sensing means thereby responds to the signal output means the response of said sensing means causes the distribution valve to assume one of said positions and, similarly, when the piston is adjacent the second sensing means and said second sensing means thereby responds to the signal output means the response of said sensing means causes the distribution valve to assume the other of said positions.

4. Apparatus for delivering in metered quantities a fluid from a source of supply comprising, means defining a hollow cylindrical chamber, a free floating piston reciprocable in said hollow cylindrical chamber defining two work chambers on each side of the piston, inlet means for each of said work chambers of fluid from said source of supply, discharge conduit means from each of said work chambers, detection means to detect the axial position of said piston, valve means responsive to the detection means for allowing flow into said work chambers alternately and out of said work chambers alternately to allow metered quantities of fluid to be discharged from the work chambers alternately as a function of the de tected lengths of stroke of said piston.

5. Apparatus according to claim 4, in which source of supply comprises a liquid refrigerant container, means to heat said refrigerant to cause said refrigerant to have a desired vapor pressure causing flow of said refrigerant to said work chambers at a desired pressure.

6. Apparatus according to claim 4, in which said detection means comprises means for sensing a magnetic field, and magnet means travelling with said piston generating a magnetic field.

7. Apparatus according to claim 6, in which said detection means comprises two means for sensing magnetic fields positionable axially at desired spaced axial positions determining the measured quantities as a function of the axial spacings between said two means.

References Cited UNITED STATES PATENTS 939,382 11/ 1909 Beard 222-250 1,932,976 10/ 1933 Lamb et al. 2,755,966 7/1956 Lindars 222250 X 2,882,999 4/1959 Morgan 222-249 X 3,119,522 1/ 1964 Schulze 222249 X 3,283,957 11/1966 Henderson 222249 X FOREIGN PATENTS 1,077,943 11/ 1954 France.

698,685 10/ 3 Great Britain.

SAMUEL F. COLEMAN, Primary Examiner.