US3521794A - Ammonia pump - Google Patents

Description

United States Patent GHice 3,521,794 Patented July 28, 1970 3,521,794 AMMONIA PUMP Dingeman Bijl, Rotterdam, Netherlands, assignor to GAF Corporation, New York, N.Y., a corporation of Delaware Filed Aug. 1, 1967, Ser. No. 657,603 Int. Cl. G01f 1.7/06

U.S. Cl. 222-309 7 Claims ABSTRACT OF THE DISCLOSURE This invention relates to an electromagnetic pump for supplying an intermittent quantity of liquid ammonia to a diazo developing machine. The pump inclu-des a slidable piston adapted to be actuated by the armature of an electromagnet. The coil of the electromagnet is intermittently energized solely by a capacitor discharge circuit responsive to a selective microswitch, the latter of which is controlled by operation of the developing machine.

This invention relates to electromagnetic pumps and, in particular, to an improved electromagnetic ammonia pump for periodically dispensing predetermined quantities of liquid ammonia from a container.

In the use of various categories of diazo-type developing machines, it frequently becomes necessary to meter predetermined amounts of liquid ammonia into the developer chambers. The quantities of liquid ammonia required depend essentially on the feed rate of diazo material being processed in the developer chambers of the machines during a given interval or unit of time. As a result, the flow of ammonia into the developing chambers of the diazo developing machines must be metered r controlled in dependence upon the feed rate of the diazo material. Other factors which alect the amount of ammonia liquid which must be supplied to the developer chambers are the varied developing conditions demanded by different types of diazo materials. This, in effect, required the development of pumps and pumping systems which convey the liquid ammonia from a container directly into the developing chamber portions of the developing machines.

Recently, in order to overcome the handling problems encountered with the use of liquid ammonia, pumps have been developed which periodically pump or convey quantities of liquid ammonia from containers into the developing machines. Although the prior art pumps have been found to be generally satisfactory when employed under ordinary or normal working conditions, problems have been encountered at various times. Thus, for example, the tendency of liquid ammonia to vaporize. at somewhat elevated temperatures under pump pressure conditions, has caused vapor-lock in the ammonia pumps, resulting in failure to provide suilicient liquid ammonia to the developing machines.

The novel and improved electromagnetic liquid ammonia pump according to the present invention, overcomes the foregoing and other disadvantages encountered in the prior art, by providing a pump which avoids vaporlock of the liquid ammonia, and which will assure an adequate supply of ammonia to the developing machine in response to a machine actuated electrical circuit energizing the pump. In effect, the present pump incorporates an electromagnetic coil which is periodically energized through a charged capacitor, by the operation of the developing machine. As a result of the coil energization, a magnetic armature which is slidably positioned within the pump will be actuated and in turn impart fluid-pumping motion to a piston member so as to `dispense liquid ammonia from a container to the diazo developing machine.

Accordingly, it is a primary object of the present invention to provide an improved and novel electromagnetic pump for supplying liquid ammonia to a diazo-type developing machine.

Another object of the present invention is to provide an electromagnetic liquid ammonia pump responsive to a charged capacitor which periodically energizes the elec tromagnetic coil of the pump for predetermined intermittent liquid ammonia feed.

A further and more specific object of the present invention is to provide a novel and improved variable displacement electromagnetic pump which is energized by a capactiance electrical circuit, and which is adapted to periodically convey predetermined quantities of liquid ammonia from a container to a diazo developing machine.

These and other objects and many of the. attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing in which there is shown a sectional view of an electromagnetic liquid ammonia pump and a schematic view of the electrical circuit for operating the electromagnetic pump in ac cordance with the present invention.

Referring now to the drawing, there is illustrated an electromagnetic ammonia pump assembly generally designated by reference numeral 1. The pump assembly 1 includes an elongate tubular member 2 formed of a nonferro-magnetic material, such as thermoplastic. The bottom portion of the tubular member 2 may be crimped inwardly as shown at 3, so as to provide clamping support for an internal piston sleeve 4. At the lower end of piston sleeve 4, a hollow stainless steel plug 5 which is locked thereto by a pin 6, seals the bottom of tubular member 2. The bottom wall 7 of plug 5 includes an aperture 8 for the passage of liquid ammonia. Internally of plug 5, wall 7 provides for a valve seat 9 adapted to support and seat a stainless steei check ball valve 10.

In the region of the upper end of tubular member 2, an electromagnetic coil assembly or solenoid generally designated by reference numeral 11 encompasses the tubular member 2 and is fastened thereto. The coil assembly 11 is encased in a suitable plastic housing 12 which provides access for an electrical conduit 13 adapted to connect the coil assembly with an electrical circuit generally designated by reference numeral 14. The lower end of plastic housing 12 may include sealing surfaces 15 which cooperate in sealing relationship with a cork or stopper 16 of an ammonia supply container 17.

Interiorly of tubular member 2, and in loosely tting relationship therewith, a generally cylindrical ferroemagnetic armature core 18 is positioned so as to be slidable along the longitudinal axis of the tubular member 2. Armature core 18 is connected by means of an elongated Wire 19 to a hollow piston 20. Piston 20, which may be formed of stainless steel, is loosely slidable along the longitudinal axis of tubular member 2, and is supported by internal piston sleeve 4. The upper portion of piston 20 and the lower end of armature core 1S may have steel cross-pins extending therethrough, about which the ends of connecting wire 19 may be wound.

Piston 20 includes a bottom wall portion 21 which is adapted to be supported on steel plug 5 when the piston is in its lowermost position in tubular member 2. Bottom wall portion 21 includes an aperture 22 for the passage of liquid ammonia. The inner surface of wall portion 21 provides for a valve seal 23 adapted to seat a stainless steel ball check valve 24.

At the upper end of tubular member 2, the latter may include internal threads adapted to cooperatively engage the threads of a hollow set screw 25 -which may be manually threaded into or out of the tubular member 2 and thereby determine the displacement of the piston.

The electrical circuit 14 for the pump assembly 1, includes a source of electrical power 26. A suitable resistor 27, diode 28, and capacitor 29 are connected in series to the source of power 26, across a single-pole two-way switch 30. In parallel relationship with capacitor 29, relative to electrical power source 26, is the electromagnetic coil assembly 11 of the pump 1.

In order to place the pump assembly 1 into operation, it is inserted into supply container 17 which contains a quantity of liquid ammonia. The lower portion of tubular member 2 extends down into the liquid ammonia, while the upper end thereof may have a suitable conduit (not shown) attached thereto for conveying pumped liquid ammonia to a developing machine under a pressure head which normally fills the tubular member 2. with ammonia.

4Electrical power source 26 charges capacitor 29, since switch 30 is normally in contact with contact point 30a. This, in effect, will leave electromagnetic coil 11 in a deenergized condition. Switch 30, however, may be a microswitch which is adapted to be actuated by a cam (not shown) attached to a rotating member of the developing machine. Thus, when the cam on the developing machine actuates microswitch 30 so as to move it to contact point 30h, the capacitor 29 is discharged across electromagnetic coil assembly 11. As a result, armature core 18 will be instantaneously displaced upwardly until stopped by set screw 25. Since hollow piston 20 will move with armature core 18, by virtue of being fastened thereto, a quantity of liquid ammonia in the upper portion of tubular member 2 will be forced through the hollow set screw 25 into the developing machine. The amount of ammonia conveyed into the developing machine is proportional to the displacement stroke of the armature core 18.

The energization of electromagnetic coil 11, and the resulting upward motion of hollow piston 20, will create a region of reduced pressure below bottom wall 21 of the piston 20, and above the plug 5. Consequently, liquid ammonia from container 17 will raise ball check valve off its valve seat 9 and enter the space below the raised bottom surface of piston 20.

As the cam portion of the developing machine, which controls microswitch 30, continues to rotate, the microswitch contact will return to contact point 30a. This, in effect, de-energized electromagnetic coil 11 by opening the circuit to capacitor 29. Simultaneously, return of microswitch 30 to contact point 30a will facilitate recharging of the capacitor 29 by electrical power source 26. Deenergization of electromagnetic coil 11 causes armature core 18 and hollow piston 20 to descend by gravity within tubular member 2. The descent of piston will cause the liquid ammonia which has collected below, as a result of lifting of ball check valve 10, to raise ball check valve 24 off its seat. This will permit liquid ammonia to pass through aperture 22 and allow the piston 20` to settle down on the sur-face of plug 5. After the piston 20 has completed its downward descent, and tubular member 2 is filled with liquid ammonia from container 17, ball check valve 24 will reseat itself and close aperture 22 under the influence of gravitational forces.

The aforedescribed operating cycle of the electromagnetic ammonia pump is then repeated each time microswitch 30 is moved between contact points 30a and 30h resulting from operation of the developing machine and rotation of the control cam on the machine.

Since the pumping action of the electromagnetic pump assemb'ly 1 is controlled by the charge in the capacitor 29, which energizes electromagnetic coil 11, low frequency of operation does not impair the efficiency of the pump as in prior art constructions, inasmuch as the speed of piston 20 is governed solely by the energization of the armature core 1-8.

Another aspect of the present pump construction is 4 that it permits some deflection of tubular member 2 during operation without detrimental effect on the action of the pump.

Although the electromagnetic pump assembly has been described with reference to Ibeing actuated by a microswitch 30 controlled through a cam on the developing machine, it becomes apparent that for more sophisticated installations, electric motors, which are driven in synchronous speeds with the developing machines, may be employed.

It should also be understood that the foregoing relates to only a preferred embodiment of the invention, and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

1. An electromagnetic pump for dispensing liquid from a bottle-necked container having a discharge opening in the neck thereof, comprising:

a vertical elongate tube having its lower end portion extending into said container through said discharge opening in such neck, said tube including valve means at its lower extremity,

a hollow piston vertically slidable within said tube, said piston including valve means at its lower extremity,

a coil encompassing said vertical tube only about its upper portion exteriorly of and above said container neck,

a vertical armature slidably disposed within said vertical tube in the region of said coil, a vertical link loosely interconnecting said armature and said hollow piston in each tube, said armature and piston being free to fall vertically downwardly under the sole iniiuence of gravity when said coil is deenergized, and

electrical circuit means including capacitance storage discharge means for energizing said coil, whereby during such energization and solely in response to such discharge, said vertical armature and said hollow piston are lifted upwardly so as to dispense liquid material from the top of said tube.

2. An electromagnetic pump as defined in claim 1, wherein the upper distal end of said tube includes means for adjustably limiting the upward displacement of said hollow piston. Y

3. An electromagnetic pump as defined in claim 2, wherein said displacement limiting means comprises a hollow set screw threaded into the upper end portion of said tube.

4. An electromagnetic pump as defined in claim 1, wherein said means link-connecting said armature and said hollow piston comprises a length of wire located within the tubular member.

5. An electromagnetic pump as defined in claim 1, wherein said electrical circuit means comprises:

a source of electrical current, and

a capacitor adapted to be charged by said source of electrical current, when said coil is deenergized,

said circuit means including a selectively operable single-pole two-way microswitch for connecting said capacitor to said source of electrical current to charge the capacitor while concurrently maintaining said coil in a deenergized condition, and means for periodically operating said microswitch whereby said charged capacitor means is discharged across said coil so as solely to energize the latter to raise the armature link and piston through a single fluid pumping stroke thereof.

6. The invention as defined by claim 5, in which said pump is secured in the container by a stopper fitting the container opening,

said stopper having a vertical hole the wall of which fits said tubular member and holds the pump in an upright position in the container.

7. The invention as dened by claim 6, in which said 0 coil is located directly above said stopper and the container.

References Cited UNITED STATES PATENTS Smith 222-333 X Strobell 222-333 X A'bbott 222-333 X Lopater 222-385 X Dunning et al. 3'18-130 X McDowall et a1 222-309 6 Wallace 103-53 XR Parker 103-53 Ray 103-53 XR Kofnk 103-53 5 ROBERT B. yREEVES, Primary Examiner HODD S. |LANE, Assistant Examiner U.S. C1. X.R.

10 10s-53, 211; 222-333, 385; 31a-13o

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