US2435053A

US2435053A - Valve and air charger for pumpstorage systems

Info

Publication number: US2435053A
Application number: US548234A
Authority: US
Inventors: Jack E Piccardo; Lino D Piccardo
Original assignee: SHASTA PUMP Co
Current assignee: SHASTA PUMP Co
Priority date: 1944-08-05
Filing date: 1944-08-05
Publication date: 1948-01-27
Anticipated expiration: 1965-01-27

Description

J. E. PICCAR ET AL 9 VALVE AND AIR CHARGER FOR PUMP-STORAGE SYSTEMS Filed Aug. 5, 1944 1 s Sheets-Shet i INVENTORS (/ACK 5. 9601200 AA/O l/Na .D. p/ccneao ZWV J. E. PICCARDQ ET AL, 4 3,53

VALVE AND AIR CHARGER FOR PUMP-STORAGE SYSTEMS Filed Aug. 5, 1944 3 Sheets-Sheet. 2

Z IEI 3 5'4) .3/ WI 5 69 5/ j W 77 79 7 S 63 l 39 xi 1 7/ g j as 72 5a a TEIE 49 INVENTORS D 3 3 M W t 5 mm um w; h we M M0 V? A. w Nw 2 s 2pm vi. m a [.0 T 3 Km m m. L S d E A! G m w M Hi 1 0m D 5 R Am. m CH A mww ym n EC J m A m A E v M V Patented Jan. 27, 1948 VALVE AND AIR CHARGER FOR-PUMP:

STORAGE S'YSTEMS Jack E. Piccardo and Lino D. Piccardo, Oakland,

Calif., assignors to Shasta Pump Company, a corporation of California Application August 5, 1944, Serial No. 548,234

a Claims. (Cl, 103-6) The invention relates to pum and storage systems wherein water or other fluid is pumped from a well or reservoir into a storage tankwhere a supply of fluid is maintained under pressure for delivery to service lines. In deep well installations, acentrifugal or other type pump may be mounted at or near the surface of the well and the well fluid elevated to the pump by means of an elector pump mounted in the. bottom of the well and operatively connected to the discharge of the surface pump. Such a system depends in its operation on the maintenance of an appropriate back pressure in the discharge line of the. 5111'. face pump. Another requisite of the system is the provision of an air head or cushion in-the tank over the water level therein, so as to maintain an adequate tank discharge pressure during delivery of water therefrom. From time to time it is necessary to replenish the air in the tank, due to absorption and other loss. An object of the present invention is to provide a combination regulator valve and air charger aflording in a single operating unit both of the functions aforesaid, viz.: the maintenance of a requisite back pressure in the pump discharge line and the periodic replenishing of the air cushion in the tank with compressed air.

In a deep well pumping system, using a centrifu'gal or other type pump at. or near the surface of the well and an ejector at the bottom of the well as above mentioned, the required and most eflicient back pressure in thepump discharge line will vary for various Well depths and pump capacities. When determined for a particular installation, this back pressure should be held substantially constant during operation of the pump when the pump discharge pressure is normally under the influence of the variable pressure load in the tank. As another object of the present invention, the valve mechanism herein provided may be adjusted to produce a desired back pressure in the pump discharge passage for the particular installation in which it is used, and

when so adjusted will automatically maintain' such back pressure during operation of the'pump, regardless of the pressure in the tank.

Air chargers, particularly of the positive displacement types, which have been heretofore available, have relied in their operation solely upon the pump suction and were dependent on a substantial suction or negative pressure at the pump intake. In many installations such as where the water supply is relatively high with respect'to the pump intake or wherea booster pump is used,'the amount of pump suction or negative pressure at the pump intake may be substantially non-existent or, in fact, the intake pressure may be-positive. As a further object of the present invention, the air charger herein provided is operated by the pressure differential generated by the pump whereby a positive and constantly dependable source of energy is available to operate the air charger, regardless of and independent of the positive or negative nature ofthe pump intake Pressure.

The invention possesses other objects and features of advantage, some of which, with the fore-.

-' going, will beset forth in the following description of the preferred form of the invention which is illustrated in the drawings accompanying and forming part of the specification. It is to be understood, however, that variations in the showing made by the said drawings and description may be adopted within the scope of the invention as set forth in the claims. 1

Referring to said drawing: Figure l is a side elevation, somewhat diagrammatical, of a deep well pressure water pump and storage system incorporating the valve and air pump mechanism of the present invention, Figure 2 is a longitudinal sectional view of a valve and aircharger unit shown in the open position of the valve.

Figure .3 is a cross-sectional view of the unit taken substantially on the plane of line 3-4 on Figure 2.

' Figure 4 is a longitudinal sectional view, similar to Figure 2 but taken at right-angles thereto and shown with the valve in closed position.

Figure 5 is" a longitudinal sectional view ofa modified form of the unit embodying the air charger only,

Figure 6 is .a cross-sectional view taken substantially on a plane of line 6-6 of Figure 5, but with the diaphragm in a reverse position.

' Figure '7 is a longitudinal cross-sectional view of a further modified form of the invention,

wherein the air charger unit is mounted directly on the storage tank.

The valve and air charger unit 5 of the present invention is adaptedvfor use with a water pressure system such as illustrated in Figure 1 of the drawing. This system includes a cenat the bottom of the intake column Ii is an ejector pump 20, including a Venturi chamber or tube I8 at the lower end of the column H which enacts with an upturned nozzle ii) for forcing the well fluid to an operating level with respect to the centrifugal pump 1. The nozzle i9 is connected to the lower end oi a pressure delivery pipe 2|, extending into the well from the discharge passage ll of the centrifugal pum 1.

Connected to the chamber l8 for admitting well fluid is a foot or check valve 22 which opens to admit well fluid when the pump 1 is in operation (and a reduced pressure is thereby created in the chamber l8) and closes to seal oil the pump lines II and 2| and the chamber I! from the well fluid on discontinuance of pump operation. A pressure responsive electric switch mechanism 23, having a pressure connection 24 to the tank and an electrical connection 29 to the electric motor 9 and source of electric power, is constructed and operates in the usual manner to cause the motor to be energized when the water level and air pressure in the tank fall to a predetermined minimum level 21 (commonly set at about 20 lbs. per sq. inch), and to'shut oil! the power connection to the motor when the .water level and pressure in the tank'have been raised to a predetermined maximum level 28 (commonly set at about 40 lbs. per sq. inch). If desired, a usual air vent valve 29 may be provided on the tank at the maximum water level so as to vent of! excess air which may accumulate in the tank.

The valve and air charger unit' 8, as illustrated in Figures 2 to 4, comprises briefly the combination of a valve part 3|, operatively positioned in the passage between the pump 1 and the tank I6 and movable to positions opening and closing such passage, a pressure responsive actuator 32 hydraulically connected to the pump I and motivated by the pressure difierential generated thereby to displace the valve part into its open and closed positions, and an air pump means 33 operatively connected to the valve part and pressure responsive actuator and. displaced thereby for pumping air under pressure into the tank.

Preferably, the several operating elements of the unit 8 are unitarily assembled in a single housing or casing 34, here composed of a generally hollow center section 36 and end sections or covers 31 and 38. Secured peripherally to the opposite ends of the center section 38 at the covers or

end walls

31 and 38 are flexible diaphragms which here provide the pressure responsive and

pump elements

32 and 33, and define with the

end walls

31 and 39,

end chambers

39 and 4| 'of variable volume depending upon the relative endwise position of the diaphragms. An intermediate wall 42 is provided across the interior of the casing between the

diaphragms

32 and 33, to provide therewith a pair of

interior chambers

43 and 44 adapted for connection by

fittings

41 and 46 provided by' the casing section 38, to the tank i6 and the discharge passage l2 of the pump 1. respectively. The end chamber 4i, separated from the high pressure chamber 44 by diaphragm 32, is adapted for connection to a relatively reduced pressure point at the pump 1. For this purpose, a passage 43 is provided in the casing in communication with the chamber 4|, and is adapted for connection, as by means of conduit 49, to the intake or suction pipe ll of the pump.

4 Where a multistage centrifugal pump is used. the conduit 49 may be connected to an intermediate stage rather than the pump intake. In either event, the function of the connection is to utilize a pressure diflerential generated by the pump when in operation to operatively displace the pressure responsive element 32 by applying the pressure differential to the opposite sides thereof in chambers 4| and 44. Thus, when the pump is in operation, the pressure differential generated thereby will displace diaphragm 32 toward the end chamber 4|. Mounted in the end chamber 4| 'between the end wall 38 and the diaphragm 32 is a helical spring 5|, which is compressed upon movement of the diaphragm 32 into the chamber 4| during operation of the pump, and which returns the diaphragm 32 to its opposite displaced position into chamber 54 upon stopping of operation of the pump when the pressures in chambers 4| and 44 equalize.

, Fluid flow through the unit from the pump to the storage tank is eflected through a passage 52 provided through the intermediate wall 42, at substantially right-angles to the longitudinal axis of the unit.- Provided substantially axially through the wall 42,- in intersecting relation to the passage 52, is a valve opening 53, which is here of substantially cylindrical form adapted to slideably receive the valve member 3|, here of cylindrical shape to lit the opening 53. Thus fluid flow through the passage 52 is normally prevented by the' positioning of the valve part therein. Formed in the valve part adjacent one end thereof, is an opening 54, which upon appropriate longitudlnal displacement of the valve member, may be brought into registration with the passage 52 to permit fluid flow therethrough. The pump side ofthe passage is ported by opening 55 into the high pressure chamber 44, so that at all times during the operation Of the pump the discharge pressure of the pump is communicated into chamber 44.

The variable end chamber 39 here provides the air pump chamber for the unit and is provided with an air intake passage 51, formed in the end cover 31, and adapted for connection to the atmosphere. An air intake check valve 58 (hereof the type used in automobile tire tubes) is mounted in the passage 51 and functions to admit air upon expansion of the chamber 39 and to close upon filling the chamber and during contraction there of. Also formed in the and cover 31 is an air discharge passage 59, which communicates the air pump chamber 39 with the tank side of passage 52. An air discharge check valve 6| is mounted in this passage 59 and automatically opens due to the pressure differential acting thereon during the contraction of the air pump chamber 39, and closes due to the reserve pressure differential at the end of the contraction and during subsequent expansion of the chamber, If desired and as here shown, a drain plug 62 may be provided in the end cover 31 for draining out of chamber .39 water which may pass the check valve 6|.

Connection of the valve part 3| to the diaphragm 33 mayfbe eflected in any suitable manner so as to maintain thereat the seal between the chambers39 and 43. As here shown,

reenforcing plates

63 and 64 are mounted on opposite sides of the diaphragm and are secured with the diaphragm to the adjacent end face of the valve part 3| by means or a machine screw 66. Connection of the opposite end of valve part 31 to the diaphragm 32 is effected in a similarmanner, by means of reenforcing plates 61 and 68 and a hollow screw 69 having a center bore 1| which registers with a longitudinal recess or chamber 12 provided in the adjacent end of the valve member 3|. Mounted in the chamber 72 is a helical spring 13, which is normally compressed between the inner end 74 of the chamber and a spring seat 16 supported against the inner end of the screw 69. A stem 11, secured to and extending axially from the end cover 38 in alignment with the bores H and I2, is adapted to enter the bore upon movement of the diaphragm 32 into the chamber 4|, to engage and displace the spring seat 16 against the resilient resistance of the spring 13. As an important feature of the present construction, the stem 11 is adjustable 1ongitudinally so as to control the resilient resistance to the full opening of the valve passage 52. As hereshown, the stem 11 is threaded through the end cover 38 and is engageable at its outer end I8 for turning to effect its. longitudinal adjustment. A cap 19 is preferably detachably secured to the end cover in enveloping relation to the stem end 18, to prevent undesirable tampering with the adjustment.

As an important feature of the present construction, the pump suction pressure is communicated to chamber 43 as well as to chamber 4|. It

will be noted from Figure 4 that passage 48 connects both of these chambers. It will further be noted that, in both the open and closed positions of the valve 3|, the tank pressure is confined to passage 52 and does not influence the pressures in any of the chamber except the high pressure chamber 44. The connection of the pump suction to chamber 43 assists in the opening of the valve member 3| against the resistance of sp ng If desired, a priming opening 8|, normally closed by threaded plug 82, may be provided in the casing at the pump chamber 44 to permit initial priming of the pump.

Operation phragm 32 and connected valve part 3| and diaphragm 33 are displaced by the spring 5| to the closed position of the valve member. In this position of the parts, chambers 4| and 43 are relatively expanded and

chambers

44 and 39 are relatively contracted.

' As water is used from the tank and the water level and pressure are reduced to the predetermined minimum, the pressure responsive electric switch 23 closes to cause energizing of the electric motor 9 and operation of the pump 1. The pressure difierential generated by the pump and applied to

chambers

44 and 4| displaces the diaphragm 32 against the resistance of spring 5| to register the open portion 54 of the valve member with the passage 52, thereby opening the passage 52 for delivery of water from the pump to the tank. This position of the parts is illustrated in Figure 2. It will be noted that as the open portion 54 of the valve member approaches the passage 52, the-stem 11 moves into engagement with the spring seat 16, to limit the Opening of the valve as a function of the pressure diiferential generated by the pump and to thereby mainto position illustrated in Figure 2, the air chamber 39 is expanded and air admitted thereto through the inlet check valve 58, the air discharge passage 59 being closed during such expansion by the check valve 6| mounted therein.

As the water level and pressure in the tank are raised to a predetermined maximum, the pressure responsive switch 23 opens and operation of the pump 1 stops. With the stopping of the pump, foot valve 22 closes, the pressures in chambers 4|, 43 and 44 equalize, and the spring 5| displaces the diaphragm 32, thereby moving the valve member to a closed position in the passage 52 and compressing the air pump chamber to its contracted position, as shown in Figure 4. On contraction of the chamber 39, air is pumped through the discharge check valve 6| into the passage 52 for delivery to the tank.

In shallow well pump installations, the ejector ump 20 may be eliminated, or in an event the back pressure in the discharge line reduced to a minimum. In such an installation, the stem 11 is preferably backed away, from the diaphragm 32, or the stem and associated spring seat 16 and spring 13 may be removed, to permit a maximum opening of the passage 52. Thus, generally, the stem 1'! is advanced or retracted in proportion to the depth of the well, being advanced for deep wells and retracted for shallow wells, and usually only needs be set at time of installation.

A modified form of the invention is illustrated in Figures 5 and 6, for use in shallow Well or other installations notrequiring the maintenance of a back pressure in the pump discharge passage or Where such back pressure, if needed, is otherwise provided by separate means. In this embodiment of the invention, the regulator valve is deleted, so that the unit consists solely of our improved air charger. This unit follows closely the construction of the main embodiment, including companion parts herein identified by the same numerals as used for the parts of the main embodiment but with a '-sign attached. In this form of the invention, the pump discharge and tank connections are both made to the chamber 44', and the pump suction is connected as in the first embodiment to chambers 43' and 4|, so as to provide actuation of diaphragm 32' against the resilient action of spring 5|. The air chamber diaphragm 33' is connected to diaphragm 32' for joint movement therewith by a stem 3| projecting through the intermediate wall 42"; During operation of the pump, the pressure differential generated thereby displaces diaphragm 32 to the An imp rtant, adaptation of the air charger illustrated in Figures and G is shown in Figure I, where the air charger is mounted directly on the tank 18" with the high pressure actuator chamber 44" in communication with the tank through passage 62". In this embodiment of the invention, the unit 6" is mounted adjacent the upper waterlevel to be maintained in the tank and iunctions toadd compressed air to the tank only when the water in the tank is above this level. This function is accomplished by the design of the air discharge check valve 8|". As will be noted from the drawing, the valve chamber Bla is somewhat larger than the ball valve 8!", and the latter normally rests on the bottom of the chamber in spaced relation to its seat 81b provided at the entrance of the air passage 59" to the chamber. So lon as the water level in the tank is below the unit 6". the valve chamber will be fllled with airwhich may pass freely by the valve 8!" into and out o! the air pump chamber 38''. As a result, upon expansion of pump chamber 39", air is withdrawn from the tank instead of the atmosphere, and on contraction of the chamber the same charge of air is restored to the tank without enacting a net change in the amount of air in the air cushion. When the water in the tank rises to the unit and enters the valve chamber Bla, the ball valve Si" is carried to its seat by the water, and thereafter, and so long as in the presence of water, the valve will perform its usual check valve action as hereinabove described, via: to coact with the other elements of the air charger to pump air into the tank. It will be noted that in this embodiment no connection is made between the unit 6" and the discharge passage of the pump. The pressure diflerential used to motivatethe diaphragm 32" is provided by the tank pressure communicated with chamber 44" and the pump intake or' other partial pump pressure connected to chambers M" and 43" by conduit 49".

We claim:

1. In combination with a pump and storage tank therefor; a regulating valve and air charger comprising, a, casing having a valve passage adapted for connection to the discharge side of said pump and to said tank, a valve member movable to positions opening and closing said passage. a plurality of diaphragm mounted in said casing and connected to said valve member for joint movement therewith between the open and closed positions thereof, said casing and diaphragms providing expansible and contractible chambers on the opposite sides of said diaphragms, the chamber on one side of each of said diaphragms being adapted for connection to the intakeside of said pump, the chamber at the opposite sideof one of said diaphragms being adapted for connection to the discharge side of said pump whereby the pressure differential generated by said pump when in operation will displace said last named diaphragm to the open position of said valve member, spring means urging said last named diaphragm and said valve member to the latters closed position upon discontinuance of pump operation, the chamber at the opposite side of said other diaphragm being formed with passages adapted for connection to the atmmphere and to Said tank, and check valves mounted in said last named passages and coacting with the expansion and contraction of said last named chamber to pump air into said tank.

2. In combination with a pump and a tank for storing under pressure water pumped thereby; a

regulating valve and air charger comprising, valve means adapted for connection between said pump and tank for controlling the now therebetwecn, fluid motor means connected to said valve means and adapted for fluid connection to the intake anddischarge sides of said pump and responsive to the pressure differential generated by said pump when in operation to displace said valve means to open position permitting flow from said pump to said tank, spring means operable to displace said motor means and said valve means to a closed position of the latter upon discontinuance of pump operation, fluid displacement means connected to and motivated by said motor means and said spring means and including a reciprocating element movable between fluid chambers, one of said chambers being adapted for connection to the intake side of said pump, the other of said chambers being adapted for connection to the atmosphere and said tank for pumping air into said tank upon reciprocation of said element.

3. In combination with a pump and tank for storing underpressure water pumped thereby; a regulating valve and air charger comprising, a casing, a plurality of diaphragms mounted therein and defining therewith on opposite sides of said diaphragms a plurality of variable sized chambers, an interior wall in said casing between said diaphragms dividing the space between said diaphragms into a pair of interior chambers, a passage extending through said .wali adapted for connection at its opposite ends to the discharge side of said pump and to said tank, a valve member .mounted for reciprocation in said wall at substantially right angles to and intersecting said passage and being connected at its opposite ends to said diaphragms for joint movement therewith to positions opening and closing said passage, one of said interior chambers being adapted for connection to the discharge side of said pump, the chamber at the opposite side of the diaphragm defining said last named interior chamber and the other interior chamber being adapted for connection to the intake side of said pump whereby the pressure (inferential generated by said pump when in operation will displace said last mentioned diaphragm to an open position of said valve member, spring means urging said last mentioned diaphragm and said valve member to a closed position of the latter upon discontinuance of pump operation, the chamber at the opposite side of the diaphragm defining said other interior chamber having air passages adapted for connection to the atmosphere and said tank, and air pump check valves mounted in said last named passages and coacting with the expansion and contraction of said chamber connected thereto to pump air into said tank.

4. In combination with a pump and a tank for storing under pressure fluid pumped thereby; an air charger for said tank comprising, a housing, a pressure responsive reciprocating element mounted in said housing, said housing having fluid chambers at opposite sides of and communicating with said element and adapted for connection to discharge and intake passages of said pump for applying a pressure diiferential to the opposite sides of said element when said pump is in operation to displace said element in the direction of the lower pressure,-spring means connected to' said element for returning the same in an opposite direction upon discontinuance of pump operation, areciprocating air pump element mounted in said housing and connected to and motivated by said first element, said housing providing fluid chambers at opposite sides or said air pump element, one of said last named chambers being adapted for connection to said pump intake passage, passage means connecting the other of said last named chambers to the atmosphere-and to said tank, and valve means coacting with the displacement of said second element to force air into said tank.

5. In combination with a pump and storage tank; an air charger comprising, a casing, a pinrality of diaphragms mounted in said casing and defining therewith a plurality of expansible and contractible chambers on the opposite sides of said diaphragms, means connecting said diaphragms for joint movement, the chamber on one side of each of said diaphragms being adapted for connection to the intake side of said pump, the chamber at the opposite side of one of said diaphragms being adapted for connection to the discharge side of said pump whereby pressure differential generated by said pump when in operation will displace said last named diaphragm toward the chamber of reduced pressure, spring means displacing said diaphragm in an opposite direction upon discontinuance of pump operation,

the chamber at the opposite side of the other of said diaphragms being formed with intake and discharge passages adapted for connection to the atmosphere and to said tank respectively, and check valves in said last named passages coacting with the expansion and contraction of said last named chamber to pump air into said tank.

6. In combination with a pump and tank for storing under pressure water pumped thereby; an air charger for said tank comprising, a casing adapted for mounting on said tank and having a passage adapted for connection therewith .at substantially the predetermined maximum water level in said tank, a diaphragm mounted in said casing and having one side thereof in communication with said passage, the opposite side of said diaphragm defining with said casing a chamber adapted for connection to the intake passage of said pump whereby the pressure diiierential acting on said diaphragm during operation of said pump will displace said diaphragm in the direction of said chamber, spring means for returning said diaphragm upon stopping of operation of said pump, a second diaphragm mounted in said casing and defining therewith an air pump chamber and being connected to said first mentioned diaphragm for joint movement therewith, passage and check valve means connecting said air pump chamber to the atmosphere, an air discharge passage connecting said air pump chamber to said first named tank connecting passage, and check valve means mounted in said air discharge passage and including a valve part responsive to the flow of water in said discharge passage and being non-responsive to the flow of air in said discharge passage whereby said check valve will close in the presence of water and remain open in the presence of air.

'I. A regulating valve and air charger for a pump and storage tank comprising, a casing having intake and discharge passages connected by a valve passage and having a relatively low plessure passage connection, a valve movably mounted in said valve passage for controlling the flow therethrough, a pressure differential responsive actuator in said casing including a pair of chambers and a fluid displacement member therebetween, one of said chambers being connected to said intake passage, the other of said chambers being connected to said low pressure passage connection, and an air pump including a second pair otchambers and a second fluid displacement member therebetween. means conhaving intake and discharge passages connected by a valve passage and being further provided with a relatively low pressure passage connection, a valve movably mounted in said valve passage for controlling the fluid flow therethrough, sp means urging said valve toward passage clos position, said casing being provided with relatively high and low pressure chambers connected to said intake passage and said low pressure connection respectively, a fluid actuated clement mounted between said chambers and being con nected to said valve for moving said valve toward its passage opening position against the resistance oi said spring means, said casing being provided with a second pair of chambers and a fluid displacing element therebetween connected to said valve for ioint movement with said first named element for joint movement, one of said second pair of chambers being connected to said low pressure connection. and air intake and discharge means for the other of said second pair of chambers. said air discharge means being con nected to said discharge passage.

9. An air charger for a pump and storage ta comprising, a casingprovided with intake and discharge passages anda low pressure passage connection, a pressure diiierential actuator in said casing including relatively high and low pressure chambers connected to said intake passage and said low pressure connection respec= tively and a fluid displacement element mounted for movement between said chambers and displaceable by the pressure diderential therein, and an air pump including a second pair oi chambers and a fluid displacement member mounted for movement therebetween and connected to said element for displacement thereby, one of said second pair of chambers being connected to said low pressure connection, and air intake and discharge means for the other of said second pair of chambers. said air discharge means being connected to said discharge passage.

10. An air charger for a pump and storage tank comprising, a casing having intake and discharge passages and a relatively low pressure passage connection, said casing being provided with relatively high and low pressure chambers connection to said intake passage and said low pressure connection respectively. a fluid actuated element mounted for movement between said chambers and being displaceable toward said low pressure chamber by the pressure differential in said chambers, spring means normally urging said element in a reverse direction, said casing being provided with a second pair of chambers and a fluid displacing element 'therebetween, means connecting said first and second named elements for joint movement, one of said second pair of chambers being connected to said low pressure connection, air intake means for the other of said second pair of chambers, and air discharge eans for said second pair of chambers, and air a 1 2,435,058 11 discharge means for said last namedchamber connected to said casing discharge passage.

warren sums m'rmn'rs JACK E. PICCARDO. Number Name LINO PICCARDO- 5 2,286,613 Fuller June 16, 1942 2,288,437 Conery et a1. June 30, 1942 REFERENCES CITED 2,303,627 Fuller Dec. 1, 1942 The following references are of record in the 1,995,611 Hapgood Mar. 26, 1985 file of this patent: 2,285,163 Knott at 8-1. June 2, 194:2