US2773957A - Altitude switch - Google Patents

Description

Dec. 11, 1956 G. J. DAVIS ALTITUDE SWITCH 2 Sheets-Sheet 1 Filed March 26, 1954 INVENTOR. d Dav/s A7 7'0/E/YEYJ Dec. 11, 1956 G. J. DAVIS ALTITUDE SWITCH 2 Sheets-Sheet 2 Filed March 26, 1954 INVENTOR. Goodwin d. Dav/s United States Patent ALTITUDE SWITCH Goodwin J. Davis, San Antonio, Tex.

Application March 26, 1954, Serial No. 418,807

2 Claims. (Cl. 200-81) This invention relates to fluid distribution systems, and more particularly to a system for controlling the distribution of liquid to a tank or the like and for controlling the level of liquid in the tank.

The main object of the invention is to provide a novel and improved fluid distribution system which involves simple components, which is substantially self-regulating, and which is provided with means for smoothing out line pressure disturbances or pulsations in the system.

A further object of the invention is to provide an improved liquid distribution system for supplying liquid to an overhead tank, said system involving inexpensive components, being reliable in operation, and being arranged to automatically provide liquid to the tank and to maintain the liquid within predetermined limits of height in the tank.

A still further object of the invention is to provide an improved fluid pressure responsive switch device adapted to be employed in a fluid distribution system for controlling an electric pump or other electrically operated device for furnishing fluid under pressure to the system, the switch being adjustable to operate at a predetermined fluid pressure in the conduit to which it is connected and being provided with means for delaying the operation thereof so that it will not respond immediately, whereby pulsations or momentary disturbances of pressure in the conduit will not cause operation of the electrical device associated with the switch.

A still further object of the invention is to provide an improved fluid pressure responsive switch adapted to be connected to a supply conduit leading to an overhead tank or the like, the switch being arranged to be operated in response to changes in pressure in the conduit. such as when the level of liquid in the tank drops below a predetermined point, and being further arranged to be actuated reversely when the level of liquid in the tank rises above a predetermined point, whereby eflicient control of the level of liquid in the tank will be obtained and whereby waste of liquid by the overflowing of the tank will be prevented.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

Figure 1 is a vertical cross sectional view taken through an improved fluid pressure-responsive switch device constructed in accordance with the present invention.

Figure 2 is an end elevational view of the control housing associated with the switch of Figure 1.

Figure 3 is an enlarged vertical cross sectional view taken on the line 3-3 of Figure 1.

Figure 4 is an enlarged cross sectional detail view taken on the line 44 of Figure 1.

Figure 5 is an elevational view showing a water distribu- I tion system constructed in accordance with the present invention and provided with fluid pressure-responsive switches as illustrated in Figures 1 to 4. 1

Figure dis a fragmentary elevational view showing the switch panel, main pump, booster pump and a portion of the water supply conduit of the system illustrated in Figure 5.

Referring to the drawings, and more particularly to Figures 5 and 6, 11 designates a water tank of the overhead type which is supplied with water through a supply conduit 12 which connects to the vertical central water main 13 connected to the bottom of the tank 11. Water is supplied to the conduit 12 from a well which is provided with an electric pump 14 to the outlet of which the supply conduit 12 is connected, through a manual control valve 15, as shown in Figure 5. The conduit 12 is preferably connected to the main pump 14 through a booster pump 16, as shown in Figure 6, the booster pump 16 being electrically operated by a suitable motor, as is the main pump 14.

The energizing circuit for the main pump 14 includes the cable 17 containing the current supply conductors, said current supply conductors being connected to a suitable source of electric power through a first pressure-responsive control switch 18 whose contacts are arranged to close responsive to a decrease in pressure below a predetermined value of the liquid in the conduit 12. As shown, the pressure-responsive switch 18 is connected by a conduit 19 to the water supply conduit 12 so that the pressure in the conduit 12 will be transmitted to the pressure-responsive switch 18, and will operate the switch in a manner presently to be described.

The conduit 19 may be connected at any desired point to the water supply conduit 12, and may, if so desired, be connected to the water main 13 so as to cause the switch 18 to respond to changes in pressure in said main, whereby the pressure conditions resulting from changes in level of the liquid in the tank 11 will be more directly transmitted to the switch 18. This alternative arrangement is indicated by the dotted lines shown at 19' in Figure 5, showing the alternative connection of the conduit leading to the pressure-responsive switch 18. As a further alternative, a similar pressure-responsive switch, shown at 18 in dotted view in Figure 5 may be mounted adjacent the tank 11 and may be provided with a conduit 20' connected to the main 13 to transmit variations of pressure in said main to the pressure-responsive switch 18'. It will be understood that the switch 18 may be connected in the electric current supply circuit for the electric pump 14 so as to control the energization of the pump, and to energize the pump in response to a decrease in pressure below a predetermined value, indicating a decrease in liquid level in the tank 11 below a predetermined point in said tank.

As shown in Figure 6, the energizing circuit for the electric booster pump 16 extends to the switch panel 21, said energizing circuit comprising a cable 22 containing conductors which are connected to a source of electric power through a liquid pressure responsive switch 23 generally smiliar to the switch 18 but arranged to close responsive to an increase in pressure above a predetermined value. It will be understood that the switch 23 as well as the switch 18 is normally open, and that the switch 18 closes in response to a decrease in pressure beyond a predetermined value, whereas the switch 23 closes in response to an increase in pressure beyond another predetermined value. Thus, the switch 23 closes after the electric pump 14 has become energized and has become primed, causing the liquid under pressure to flow to the booster pump 16 and to produce an increase in pressure at its outlet conduit 25 which is of a value above that required to close the switch 23. The switch 23 has its fluid pressure responsive means connected to the outlet conduit 25 of the booster pump 16 by a conduit 26, whereby the pressure in the conduit 25 is transmitted to the switch 23, causing the switch to close and to energize the boosterpump 16. This assures the prim 3 ing of the main pump 14 after said pump has become energized.

The liquid is pumped into the supply conduit 12 and flows therefrom to the main l3, and into the overhead tank 11. After the liquid has reached a predetermined level in the overhead tank 11, the liquid pressure resulting therefrom is transmitted to the switches 13 and 23, and when employed, to the switch 18'. As will be presently described, these switches are arranged to respond to predetermined upper pressure limits to open the switches 18, 18 and 23, when the upper predetermined limit of pressure has been reached.

As shown in dotted view in Figure 6, the booster pump control switch. 23 may be connected to the conduit 27 between the main pump 14 and the booster pump 16, as by the conduit shown in dotted view at 26, instead of to the outlet conduit of the booster pump, so that the switch 23 will respond to the liquid pressure at the outlet of the main pump 14 instead of the pressure of liquid forced through the booster pump 16.

Referring now to Figures 1 to 4, the fluid pressure responsive switch 18 comprises a bottom chamber 34 having the top wall 31 to which is connected the conduit 19 leading to the source of variable pressure, for example, to the water supply conduit 12. The chamber contains a quantity of suitable fluid, such as mercury or the like. Any other suitable liquid or gas may be employed. The chamber 39 is formed with a depending axial reduced portion 32 containing the needle valve 33, said needle valve having a threaded body 34 threadedly engaged in an axial threaded bore in the reduced portion 32 and having the stem 35 projecting through a gland 36 provided in the bottom end of the portion 32. Designated at 37 is a second chamber of substantial height secured on the top wall 31 of the first chamber, said second chamber having a bottom wall 33 to which is connected a depending vertical tube 39 in the bottom end of which the needle valve 33 is received. Secured in the bottom end of the tube 39 is the annular valve collar 49 which has a downwardly flaring bore cooperating with the upwardly tapering conical tip of the needle valve 33 to define an annular restriction between the main chamber 30 and the auxiliary upstanding chamber 37.

it will be understood that the mercury in the main chamber 30 will be forced upwardly into the chamber 37 by the pressure applied to the main chamber from the conduit 19, and that the mercury in the auxiliary chamber 37 will rise to a level corresponding to the applied pressure.

The top Wall 31 of the main chamber 36 is provided with a suitable vent valve 43 to allow air to be discharged from the main chamber 30.

The auxiliary chamber 37 is provided with the top wall 41 to which is secured the rectangular control housing 42. Centrally secured to the top wall 41 and in communication with the auxiliary chamber 37 is the expansible bellows 44 which is arranged to change its volume in response to the change in pressure applied to the main chamber 30 by the fluid in conduit 19, inasmuch as the mercury in the auxiliary chamber 37 will exert pressure on the air thereabove in chamber 37 and in the bellows 44 and will expand said bellows in response to an increase in fluid pressure, as will be apparent from Figure 1.

Pivoted at 45 in the control housing 42 is a bell crank lever 46 having a substantially horizontally extending lower arm 47 engaging the top end of the bellows 44 and having a'substantially vertically extending arm 48 which is connected by a coiled spring 49 to the end of a screw 50. The screw 50 is threadedly engaged in a rotatable adjusting sleeve 51 mounted in the vertical end wall 52 of the housing 42, the sleeve 51 being provided with the external adjusting knob '53 having thereon a-suitable scale which may be rotated with respect to a stationary index member 54 provided on the wall 52, the seale on the knob 53 being calibrated in terms of water levels in tank '11,

and the position of the scale with respect to the index member 54 corresponding to the maximum water level desired in the tank. It will be understood that by rotating the member 51, the screw 50 is adjusted inwardly or outwardly, to increase or decrease the tension of the spring -559, and to thus increase or decrease the normal bias exerted by said spring on the bell crank lever 46, and therefore to increase or decrease the normal downward force exerted by the arm 57 on the top end of the bellows 44.

A U-shaped stop bracket 46 is secured to a side Wall of; housing 42 having arms extending on opposite sides of tr e lever arm 48 to limit rotation of said lever arm, as shown in Figure 1.

Rigidly secured to the arm 47 of the bell crank lever 46 is the substantially horizontally extending arm 55 which is connected by a link bar 56 to a disc member 5? on which is mounted the mercury switch 58. The disc member 57 is provided with the oppositely extending axial pivot pins 59, 59 which are rotatably received in pivot cups 60, 60 carried on the pivot bracket 61 which is secured to the end wall 62 of the control housing 42. One arm of the pivot bracket 6i is provided with the parallel fingers 63, 63 which carry the opposing stop screws 64, 64 disposed on opposite sides of a stop projection 65 secured on the disc 57 to limit rotation of the disc between predetermined limits, namely, to limit rotation of the disc to a relatively small angle, of the order of 30 or less.

When the disc 57 rotates clockwise past its intermediate position, as viewed in Figure l, the mercury switch 58 closes and remains closed until the disc 57 has been retated counterclockwise past its intermediate position, as by the expansion of the bellows 44. The disc 57 is yieldingly retained in its intermediate position by a spring biased detent element 65 which engages in a V-shaped notch 66 formed in the periphery of the disc 57. The detent element 65 is secured to the lower end of a coiled spring 67 which is retained in a guide sleeve 63 secured in a vertical position surrounding the spring 67 and having the top bracket portion 69 secured to the top wall 70 of the switch housing 42. Secured to the top end of the spring 67 is an abutment element 71 which is engaged by the head 72 of a plunger 73 slidably supported in a guide sleeve 74 extending through the housing top wall 7% and being integrally formed on a bracket plate 75 secured to the bottom wall of an auxiliary housing 76 secured on the top wall 70 of the main control housing 42. The plate 75 is formed with a pair of upstanding lugs 77 bctwen which is pivoted the lever 78 having the bottom arm '79 which overlies the top end of the plunger 73, as shown in Figure 3. Secured to the top end of the arm 79 is an abutment pin 80.

Secured in the front wall 81 of the auxiliary housing 76 is a guide sleeve 82 in which is rotatably mounted a shaft 83 having secured to its inner end a wedge-shaped disc member 84 and having secured to its outer end an adjusting knob 85. The wedge-shaped disc 84 has its inclined surface in engagement with the abutment pin 30, the pin being biased into engagement with the inclined surface of the wedge-shaped disc 84 by the force of the spring 67, transmitted through plunger 73 to the bottom arm 79 of the lever 78. It will be readily apparent that by adjusting the knob 85, the lever 78 may be rotated about its pivots 86 to a desired position, whereby the downward force exerted on the spring 67 by the plunger 73 may be regulated within a reasonable range. This provides a means of varying the force exerted by the detent element 65 on the notch 66, and hence provides a means of varying the amount of extra force required to rotate the disc member 57 from its intermediate position after the detent element 65 has entered the notch 66.

The front Wall 81 of the auxiliary housing 76 is provided with a suitable scale 88, calibrated in feet and inches, and the knob has a pointer 89 which, when adjusted along the scale 88, provides a desired level differential in the tank 11 between the level at which the switch 53 closes and the upper level at which the mercury switch 58 is caused to open. The maximum height of liquid in the tank is of course established by the adjustment of the control knob 53, which controls the tension of the spring 49.

The mercury switch 58 is connected by suitable wiring in the energizing circuit of the electric pump, in the manner above explained, so as to energize the pump when the liquid pressure drops below a predetermined level, corresponding to a predetermined altitude of liquid in the tank 11. A manually operated switch 91 is provided in the control housing 42 which is connected across the mercury switch 58, and enables the operator to manually close the energizing circuit for the electric pump, whenever desired. The switch 91 is normally open, namely, at times when automatic control of the tank level is desired.

It will be understood that operation of the switch devices 18 and 18' is substantially the same, namely, when the fluid pressure drops below a predetermined value, determined by the setting of the limit control knob 53 and the diiferential control knob 85, the decrease in pressure in the auxiliary chamber 37 allows the bellows 44 to contract and allows the spring 49 to rotate the bell crank lever 46 clockwise, as viewed in Figure 1. This rotation is transmitted by the link 56 to the disc member 57, and when the force applied by the spring 49 is suflicient, the disc 57 is rotated clockwise, as viewed in Figure 1 moving the disc away from its normal intermediate position and causing the mercury switch 58 to close. This energizes the pump 14, and, as will be presently explained, the booster pump 16, causing liquid to be pumped through the conduit 12 to the main 13 and into the tank 11. As the level of liquid in the tank 11 rises, the pressure transmitted through the conduit 19 to the lower chamber 30 of the switch is increased, causing the mercury to move upwardly in the auxiliary chamber 37, and thus causes the bellows 44 to expand. When the liquid level in the tank has reached a height suflicient to overcome the combined effects of the springs 49 and 67, the disc member 57 is rotated counterclockwise past the intermediate position of the disc, causing the mercury switch 58 to open, and causing the electric pump to become deenergized. As the level of liquid subsequently drops in the tank, the bellows 44 will contract, allowing the disc 57 to rotate to a position wherein the detent element 65 enters the notch 66, but as long as the liquid level remains above a predetermined low limit, the mercury switch 58 remains open. When the level of liquid in the tank drops below said low limit, the mercury switch 58 closes, by the process above described.

The needle valve 33 is adjusted to provide an annular restriction between the main chamber 30 and the auxiliary chamber 37, whereby the flow of mercury from the main chamber 30 to the auxiliary chamber 37 and return flow of said liquid is retarded, thus preventing response of the system to momentary pulsations of pressure or other short term pressure disturbances. The degree of retardation may be regulated by adjusting the needle valve 33 to provide a desired restriction between the chambers 30 and 37.

The booster control switch 23 is similar in construction to the control switch 18 except that it is arranged to close on an increase in fluid pressure in the conduit 25 or conduit 27, above a predetermined value and to open when said pressure drops below a lower predetermined value. Thus, the booster pump 16 will remain in operation from the time that the main pump 14 becomes primed until the main pump 14 is deenergized by the opening of its control switch 18. As shown in Figure 6, a check valve 16' is employed between the conduit 12 and its control valve 15 and the outlet conduit of the booster pump 16 to prevent the switch 23 from being affected by changes in pressure in the conduit 12.

While a specific embodiment of an improved fluid distribution system and fiuid pressure responsive switch means forming a part thereof have been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

1. In a fluid pressure-responsive switch, a first chamber adapted to be connected to a fluid conduit subject to changes in pressure, a second chamber, conduit means extending through the first chamber and connecting said chambers, a restriction in said conduit means to provide a time delay between a change in fluid pressure in the first chamber and a corresponding change in pressure in the second chamber, an expansible flexible chamber connected to and communicating with said second chamber, a pair of contacts, and means engaging said expansible chamber and being formed and arranged to open and close said contacts in response to changes in volume of said expansible flexible chamber, said last-named means comprising a support mounted on said second chamber, a rotary member mounted on said support, a mercury switch secured to said rotary member, adjustable detent means frictionally engaging said rotary member, a lever pivoted to said support and engaging said expansible flexible chamber, link means connecting said lever to said rotary member, and adjustable spring means biasing said lever toward engagement with said flexible chamber, whereby the force required to rotate said rotary member may be adjusted.

2. In a fluid pressure-responsive switch, a first chamber adapted to be connected to a fluid conduit subject to changes in pressure, a second chamber, conduit means extending through the first chamber and connecting said chambers, a restriction in said conduit means to provide a time delay between a change in fluid pressure in the first chamber and a corresponding change in pressure in the second chamber, an expansible flexible member connected to and communicating with said second chamber, a pair of contacts, and means engaging said expansible chamber and being formed and arranged to open and close said contacts in response to changes in volume of said expansible flexible chamber, said last-named means comprising a support mounted on said second chamber, a rotary member having an arcuate periphery provided with a detent notch, said rotary member being rotatably mounted on said support, a mercury switch secured to said rotary member, an adjustable spring detent mounted on said support and yieldably engaging in said notch, a lever pivoted to said support and engaging said expansible flexible chamber, link means connecting said lever to said rotary member, a spring connecting said lever to said support and opposing the expansion of said expansible chamber, and means adjusting the tension of said spring, whereby the force required to rotate said rotary member may be adjusted.

References Cited in the file of this patent UNITED STATES PATENTS 1,293,547 Reese Feb. 4, 1919 1,461,470 Ackley July 10, 1923 1,734,233 Shannon et a1. Nov. 5, 1929 1,762,219 Faber June 10, 1930 1,980,095 Rowley Nov. 6, 1934 2,043,579 Edrington et a1. June 9, 1936 2,274,558 Murray Feb. 24, 1942 2,440,981 Smith May 4, 1948 FOREIGN PATENTS 353,225 Great Britain July 23, 1931 528,580 Great Britain Nov. 1, 1940 931,059 France Sept. 15, 1947

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