US2481612A - Liquid level switch - Google Patents

Description

Patented Sept. 1.3, 1949 f 2,481,612 LIQUID LEVEL SWITCH Ralph A, Nicholson, Chicago, Ill., assignor to Raymond T. Moloney, Chicago, Ill.

Application August 20, 1945,' Serial No. 611,634

2 Claims.

This invention pertains broadly to liquid level kcontrol devices, and has as its principal object the provision of a highly elicient and simpliiied control of this character especially suited for use vwith beverage dispensing equipment utilizing carbonated water, it being understood, however, that the control is not limited to such application or use.

Equipment designed for dispensing carbonated water or beveragesvcommonly includes a receiver for the water or liquid and a connection to this receiver from a source of carbonatlng gas, such arrangements frequently being designated in the art as carbonators or mixers, this practice arising from the commercial expediency of distributing the carbon dioxide gas in replaceable drums or cylinders Vwhich are replaced when exhausted by fully charged cylinders. n

Heretofore, elaborate level rcontrol arrangements of pressure-sensitive valves, switches, flotation devices and the like have been employed for vcontrolling the operation of a pump to force water into the carbonator against the pressure of the carbonating gas, and such prior arrangements, in

addition to being relatively complex and costly, as

well as bulky or space-consuming, require careful adjustment, supervision. and frequent servicing,

The present invention provides a control which is very small, compact, simple, and inexpensive; it

is also highly reliable in operation, sensitive to 'exposed to the gas pressure and the liquid head pressure, in opposition, and jointly displaced to actuate a switch when the head-pressure falls below a desired value;

Another object is the provision of a pressure- Vsensitive switch of general application, and

especially suited to installation on a carbonator or the like, and including a chamber having a pair 'of jointly movable diaphragrns therein and sealed so that the chamber is divided into a central compartment in which the switch means 'is situated for actuation responsive to displacement of the diaphragme in onedirection, together with separatelysealed compartments into one of which leads a communication with the gas pressure in the carbonator, and into the other of which the head of water in the carbonator communicates with one of the diaphragms, such that Iwhen the head of water yfalls below the desired point, the diaphragms are displaced by gas pressure and/or spring means to actuate the switch and start the liquid pump motor to retore the level.

@ther objects andV aspects of novelty in the nvention relate to details of construction and operation of the preferred embodiment described hereinafter in view of the annexed drawing in which: l

ig. 1 is a vertical section through a carbonating receiver and the novel control means;

Fig. 2 is a horizontal section through the control means along lines 2--2 of Fig. 1.

Referring to Fig. l, a sealed carbonating receiver it is provided with connection Il leading to the liquid or water supply (not shown), from which the liquid is pumped by an electrically driven or controlled pump, not shown, of which there are numerous types known in the art.

.il conduit or connection l2 leads from the receiver, at the top thereof, to the usual supply cylinder of carbonating gas under considerable pressure, 30 pounds or more, the purpose of the electrically driven or controlled pump means being force the water from the supply source into the receiver against this gas pressure, the gas and water or other liquid or beverage becoming intermingled in the receiver, and the gas tending to force the water from the receiver into the outlet cr dispensing line connection I4 near the bottom or" the receiver.

In the illustrative embodiment, it is assumed that the liquid level is to be maintained at the point l5 in the receiver, and the novel means for accomplishing this includes the control generally indicated at l 6.

In a preferred formr of construction, the control !6 includes a central metal ring il having upper and lower flanges I8' and I9, and recessed or concaved end vcaps or pieces 20 and ill each having ilange portions 28A and ZIA adapted to seat against the flange portions of the central ring, thus forming a main chamber which is attached to the bottom of the carbonator or receiver lil by welding or the like of upper end piece 2l to the bottom of the receiver, there being an opening 21B of predetermined size in this upper end piece, which opening registers with a like opening lA in the bottom of the receiver.

Interiorly of the main control chamber is an upper membrane or diaphragm clamped in sealed condition between flanges I8 and 2IA by screw means 25 in the latter, while a similar diaphragm 27 is sealingly clamped in the lower part of the main chamber between anges I9 and 20A, as by screws 28.

The membranes or diaphragms 25 and 21 thus divide the main chamber into a central compartment or chamber 30, which is sealed cfr from an upper compartment or chamber 3l by upper diaphragm 25, and a lower compartment or chamber 32, which is sealed off by lower diaphragm 21.

The two diaphragms are interconnected by a stud in axial alignment with the centers of these diaphragms and attached to the latter by screws Se through sealing washers 40, so that the diaphragms can move jointly up, and down.

Control switch means for rthe liquid pump is situated in the central chamber, and includes. a pair of switch blades 42 and 43 secured and biased in normally open-circuitv condition between the usual insulating wafers 44 on a mounting bracket 45 welded to the interior of this central chamber, there being also an operating blade 46 having an insulating stud 4i adapted to bear up against the lower switch blade 43 to push the latter into cir cuit-closing engagement with the companion switch blade e2, there being an arm or extension 48 on the operating arm extending into driving engagement with the diaphragm-connecting stud 35, as by engagement in a slot 49 therein. Thus, when stud 35 moves upwardly, as by displacement upwardly of the diaphragms, switch blades 42-43 will be closed together by upward movement of insulated stud 'l.

Means for causing operation of the switch 42- d3 responsive to lowering of the liquid level inthe receiver, includes a small spring expanding upwardly against the lower diaphragm assembly in the lower chamber 32 and of suiiicient strength to displace this lower diaphragm upwardly to close switch 1li-[i3 provided the head of water above openings IBA--IB bearing on the upper diaphragm 25 is less than aV predetermined amount.

Normally, when the liquid level is at the point I5, this diaphragm-operating head is adequate to resist the upward eiiort of spring 50, but when the water level falls to the point IEA, the head of water (indicated in dash-dot lines in the receiver) is insucient to overbalance spring 50, and the latter pushes the lower diaphragm, and hence the upper one as well, upwardly causing switch operating arm d8 to be carried upwardly with a consequent closing of switch 42--133 by stud lil, thus closing a pump motor operating circuit via conductors eZA and 43A.

In order to assure positive operation of the control i6 at all times and under all practical gas operating pressures in the dispensing system, the gas pressure in receiver I is balanced-out by means of a balancing connection or line 6U communicating from the lower chamber 32, as at lil, into the upper portion of the receiver, and above the normal water level l5 therein, as at 62.

Since the gas pressure in receiver i6 is exerted downwardly against the upper diaphragm 25, and simultaneously upwardly against the lower diaphragm 21, in opposition to the effort against the upper diaphragm, the net effect of this gas pressure on the diaphragms is substantially zero, and the diaphragm system is therefore sensitive only to variations in the head of liquid in receiver I0, and a highly satisfactory sensitivity to variations in liquid level becomes possible by selection of an 4 appropriate spring tension for spring 50 depending on the level which is to be maintained.

The central chamber 30 is sealed off and no sealing precautions are necessary for switch leads dBA-43A; and there is adequate room in this chamber for installation of various types of switch other than that shown, it being possible to employ a small snap-action switch, if desired, in place of the blade switch described.

As heretofore mentioned, switch leads 42A- 43A are adapted to be connected in the control circuit (not shown) for an unshown pump motor to force replenishing supply of water into the carbonator or receiver I0. Such motor pump arrangements are known in the art and do not per se constitute part of the invention, the principal invention being in the provision of a switch means actuated by a liquid head subjected to gas pressure, and means for balancing out the effects of the gas pressure so that the liquid level or head is the controlling factor, the` invention also extending todetails of the control device per se.

The foregoing specic description is not in.- tended to be limiting excepting as may be ex.- pressly provided by the appended claims fairly construed in the light of the prior art.

Having thus described my invention, what I claim as new and desire toA protect by Letters Patent of the United States is:

1. A device of the class described comprising upper and lower chambers, said upper chamber adapted to contain liquid and gas under pressure, said lower chamber being ot unitary con;- struction and having a pair'of parallel, spacedapart diaphragms one above the other therein and dividing said lower chamber into an upper compartment, a lower compartment, and a middie compartment, said compartments all sealed 01T from eachother and saidupper compartment communicating. vertically into said upper chamber such that a head of liquid and gas therein exerts a force on the uppermost of said dia'- phragms, a pressure-equalizing gas connection between the upper region of said upper chamber and the said lower compartment, and a switch situated in said middle compartment, wherein itis sealed against moisture and gas fromv said other compartments, and means mainly in said middle compartment opera-tively interconnecting said diaphragms with each other and with said switch for operation of the latter responsive to displacements of said diaphragms, jointly, predetermined amounts,.together with spring means yieldingly urging saidl diaphragms upward with force to be ba-lancedj by a determined volume of liquid in. said upper chamber.

2. A liquid level control comprising upper, lower, and median chamberV portions formed to iit together and define a unitarychamber..a diaphragm sealingly clamped between said, upper and median chamber portionsand another diaphragm clamped sealingly between saidv lower and media-n chamber portions, said. diaphragms being in approximate parallelism and. one in alignment above the other such ,thatgsaidfunitary chamber is divided into upper, middle, andlower compartmentssealed of from each otherstud means operativelyv interconnecting said diaphragms in said middle compartment, a switch in said middle compartnnant` :mdfoperatviely1 as.- scciated with said diaphragms by means or a projection therefrom extending into a slot in said stud suchthat4 baclrand.v forth motions of the stud responsive to correspondingA displacements of said diaphragms will actuate said switch, REFERENCES CITED spring means normally urging said diaphragms jointly in a direction toward said upper -com- The following references are of record in the partment, a pressure opening communicating into 111e 0f this patenti said upper compartment for communicating` a 5 UNITED STATES PATENTS head of liquid pressure to the upper--most dlaphragm, and pressure-balancing means includ- Number N a'me Date ing an opening into said lower compartment for 916,957 Dur (11n, J1 Mal- 30, 1909 introduction therein of a pressure acting on said 973,103 Basllan DBC. 6, 1910 head of liquid pressure .but in addition to the 1o 1,847,086 Gargan Mar. 1, 1932 latter, such that the loading effect of said addi- 1,952,265 Leland Mal'- 27, 1934 tional pressure on said diaphragms is substanti- 2,031,502 Powell Fell 18, 1936 ally balanced out, said switch being sealed off 2359,163 SOIIIGS et al Sept. 26, 1944 from substances in either of the upper or lower compartments. 15

RALPH A. NICHOLSON.

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