GB2177486A - Improved method and apparatus for servicing an air conditioning and refrigeration system - Google Patents

Abstract

An apparatus for charging and monitoring refrigeration systems and the like includes a manifold 105 having a passageway therein terminating in four ports, a single pressure gauge 101 or other measuring device in fluid communication with one of said ports, valve means 112, 113, 114 in fluid communication with each of the other ports, and flexible conduit means 80A, 80B, 80C for connecting each valve means 112, 113, 114 to a selected portion of the system or to a supply 25 of refrigerant. <IMAGE>

Description

SPECIFICATION Improved method and apparatus for servicing an air conditioning and refrigeration system Background of invention This invention relates to methods and a ppa ratus for transferring a flow of pressurized gas or liquid, and more particularly relatesto improved meansforcon trolling the inputofa refrigerant to an aircondition- ing system and the like.

Itiswell knownthatan air-conditioning system for a dwelling is usually composed of a section for heating the airwithin the dwelling, and a separate section for cooling the airwithin the dwelling, as well as suitable temperature sensors and controls for activating orde-activating one or both sections in order to maintainthetemperature ofthe airwithin a preselected range. In addition, atypical airconditioning system will usually include devices for establishing and maintaining other comfort parameters such as humidity, etc.

Insofar as the cooling section is concerned, most are basically designed to operate on the compression principle, wherein a refrigerant such as ammonia ora gaseousfiurocarbon is vaporized during passage through a coil assembly. Evaporation of the liquid refrigerantchillsthe coil assembly, and if airsoughtto be cooled is blown over the chilled coils, heatwill transfer out ofthe airand through the coils to the refrigerant flowing therethrough.

The refrigeration system is a hermetically sealed unit, however, and therefore the vapororized refrigerant which has absorbed heat while passing through the evaporatorcoil is transferred to a compressorwhich applies pressure to reducethevolume ofthe gaseous refrigerant. Thereafter, the heated vapor is transferred under pressure to another coil assembly which acts to convert the heated vapor to a liquid and which also removes the heat, whereby the liquid refrigerant is then recycied to the evaporator coil and again vaporized as hereinbefore described.

Itshould be noted that, a refrigeration system of this type is a closed unit wherein the refrigerant is continually re-cycled between a vapor state and a liquid statewhileflowing continuallythroughthe system under suitable pressures. Itwill therefore be apparent that the refrigerant is continually expanding and contracting,within the system, and this con tinually subjects the system to strains duetothe changes in temperature.

Most refrigeration systems include a tank or other reservoir for accomodating much of this expansion and contraction of the refrigerant, and forthereby re- lieving much of the strains to which the system would otherwise be subjected. Nevertheless, it is a fact that freon or another such refrigerant is capable of escaping (albeitslowly)through even avery minute fissure or discontinuity in the system, and therefore it is periodically necessary to replenish the supply of refrigerant within the system.

In principle, it is a relatively simple task to periodically introduce refrigerant and the like into the average refrigeration system to replace such loss. It should be noted, however,thatthis must be done ina manner consistent with maintaining the various pressures, which are necessary at different locations through the system, and which must be maintained to properly and effectively operatethe system. Furthermore, it may be necessary to re-establish such pressures atthe appropriate levels, before the system can be effectively operated. In fact, it is often desirabletocheckthevarious pressures through the system, in orderto confirm thatthe supply of re- frigerant within the system has become inadequate for the purposes of the system.Accordingly, special devices and apparatus have been devised to facilitate these tasks.

In the past, such testing and refrigerant addition has been accomplished by means of a manifold type of device, and such exemplary manifold devices are setforth, for example, in U.S. Patent Nos. 3,208,232; 3,243,969; 3,645,496; and 3,785,163. Such devices include both a high side pressure gauge and a low side pressure gauge, the purpose of which is to provide an indication of both pressures on the high and low sides of the compressor, respectively. However, the valves which control the flow to such gauges cannot be opened simultaneously, since otherwise the low sidegaugewill be damaged if the pressure onthe high side is greater than the retard margin ofthe low side gauge.

When charging an air conditioning system, care must also be exercised to avoid overcharging ofthe system and creating an internal pressure which exceeds the design limits ofthe system. This is difficult with the devices of the prior art because they employ thumb-screw orwater-faucettype valves, and such valves cannot be opened or closed with sufficient rapidity to achieve effective control over the system.

Another problem with the devices ofthe prior art is that when the system is being charged with re frigerant,thatthe low side gauge does notactually indicated the true pressurewithinthe "low pressure" side ofthe system. Instead, such a device merely reads the discharge pressure existing at the output of the tank containing the replacement freon. Thus, whenever the serviceman wishes to verify actual low pressure existing in the refrigeration system, he must first close the "low side" valve which, because of its faucet design, is slow and clumsy to accomplish.With further regard to the false "low side" pressure readings indicated on the low side gauge while the system is being charged, it is often necessary or at least desirableto first checkthe new supplytank shut-in pressure, within the replacement tank, because the replacement tank may actually be approaching evacuation unbeknownsttotheservice- man. In the priordevices,this cannot be doneeffectively, unless the low side hose isfirst disconnec- ted, and the low side nipple is then capped off, before low side valve is opened to connect the replacement tanktothe low side gauge.

In contrast to the devices exemplifying the prior art, the present invention seeks to overcome and correctsuch disadvantages, since only a single gauge is used to measure both negative pressures below zero, as well as positive uptothe same limits as the high side gauges, in the prior devices. There is also employed slide valves of novel design which permit instantaneous shut-offto eliminate or greatly reduce the chances of overcharging the system, which is especially important since the present device is designed to be held in one hand and therefore operation thereof is a function ofthe parallel alignment ofthe valves.Such slide valves render low side system checks convenientto make, because such low side system checks can be rapidly and easily achieved with no needto disconnectany hoses but merely by opening the low side slide valve. This is becausethe low side valve in the priorartdoes not open orclose the low side line, but instead connects or disconnects the replacementtankto from the low side ofthe refrigeration system and the low side gauge, whereas in the present invention, the low side slide valve closes or opens the low side of the system to or from the replacement tank as well as the low side gauge.

These disadvantages ofthe prior art are overcome with the present invention, and commercially acceptable embodiments of an air conditioning system monitoring and recharging manifold device are provided herein.

Summary ofinvention This invention relates to monitoring and control device having a manifold with a passageway therein terminating in at least four different ports, a single pressure gauge in fluid communication with one of said ports and being capable of measuring both the high side pressure and the low side pressure in the system being monitored, and a separate valve means interconnected with each ofthe other ports for controlling the flow of fluid between said passageway means and that port.

This invention relates to an air conditioning and refrigeration system monitoring and refrigerant recharging device having a manifold with passageway meansthereinterminating in at leastfour ports, a single pressure gauge in fluid communication with one of said ports and being capable of measuring both the high side pressure and the low side pressure in the air conditioning and refrigeration system being monitored, and valve means in fluid com munication with each ofthe other ports for controlling the flow of fluid to and from said passageway means.

This invention also relates to an air conditioning and refrigeration system monitoring and refrigerant recharging device having a manifold with passageway meanstherein terminating in atleastfourports, a single pressure gauge in fluid communication with one of said ports and being capable of measuring both the high sidefluid pressure and the low side fluid pressure in the air conditioning and refrigeration system being monitored, and slide valve means in fluid communication with each ofthe other three ports for controlling the flow offluid to and from said passageway means.

This invention further relates to an air conditioning and refrigeration system monitoring and refrigerant recharging device having a four-way manifold member including fluid flow passageway means thereinforconducting refrigeranttoandfromtheair conditioning and refrigeration system, said passageway means terminating in at leastfourfluid flow ports, a single fluid flow pressure sensitive measuring gauge in fluid communication with one of said ports and being capable of determining both the high sidefluid pressure and the low side fluid pressure existing in the air conditioning and refrigeration system that is being monitored, and slidevalve means being in fluid communication with each ofthe otherthree of said ports for controlling the flow of refrigerant to and from said passagewaymeansfrom the airconditioning and refrigeration system that is being monitored and recharged.

In one particularly ideal embodiment of the present invention there is provided a valve having an elongated cylindrical body member with a first axially extending passageway therein open at one end and closed and terminating within the interior ofthe body cylinder at the other end, a second axially extending passageway in the cylinder body and being open at one end and closed and terminating within the interior of the body member at the other end, the passageways being separated one from the other at their closed ends, a first and a second radially extending port in said body memberwith one port being influid communication with the closed end of one of the passageways and the other port being in fluid communication with the closed end of the other passageway, an annular slide member in surrounding re lationship to a portion ofthe body member and having a single o-ring at one end and a pair of spaced o-rings at the other end, said slide member including a chambertherein between said single o-ring and said pair of spaced o-ri ngs, whereby when said slide member is in a first location on the body memberthe chamber provides fluid communication between the ports whereas when said slide member is in a second location on the body memberthe ports are isolated one from the other.

In a further particularly ideal embodiment ofthe present invention there is provided an air conditioning and refrigeration system monitoring and refrigerant recharging device having a four-way manifold member including fluid flow passageway means therein for conducting refrigerant to and from the air conditioning and refrigeration system, said passageway means terminating in at least four fluid flow ports, a single fluid flow pressure sensitive measuring gauge in fluid communication with one of said ports and being capable of determining both the high sidefluid pressure and the low side fluid pressure existing in the air conditioning and refrigeration system that is being monitored, slide valve means being in fluid communication with each ofthe other three of said ports for controlling theflow of refrigerantto and from said passageway means from the air conditioning and refrigeration system that is being monitored and recharged, the three slide valves being substantially aligned and parallel with one another and extending downwardly from said manifold on onesidethereofandwiththegauge being located on the other side of said manifold op posite the valves and extending upwardlytherefrom.

In another particularly ideal embodimentofthe presentinventionthere is provided an airconditioning and refrigeration system monitoring and re frigerant recharging device having a four-way manifold member including fluid flow passageway means therein for conducting refrigerantto and from the air conditioning and refrigeration system, said passageway means terminating in at leastfourfluid flow ports, a single fluid flow pressure sensitive measuring gauge case in fluid communication with one of said ports and being capable of determining both the high side fluid pressure and the low side fluid pressure existing in the air conditioning and refrigeration system that is being monitored, slide valve means being a fluid communication with each ofthe other three of said ports for controlling the flow of refrigerantto and from said passageway means from the air conditioning and refrigeration system that is being monitored and recharged, the three slide valves being substantially aligned and parallel with one another and extending downwardlyfrom said manifold on one side thereof and with the gauge being located on the other side of said manifold op posite the valves and extending upwardlytherefrom, and a hanger bracket connected at one end to the back of said gauge case and extending outwardly therefrom. the three slide valves being substantially aligned and parallel with one another and extending downwardly from said manifold on one side thereof and with the gauge being located on the other side of said manifold opposite the valves and extending upwardlytherefrom.

In another particularly ideal embodiment of the presentinventionthere is provided an airconditioning and refrigeration system monitoring and refrigerant recharging device having a four-way manifold member including fluid flow passageway means therein for conducting refrigeranttoandfromtheair conditioning and refrigeration system, said passageway means terminating in at leastfourfluidflow ports, a single fluid flow pressure sensitive measuring gauge case in fluid communication with one of said ports and being capable of determining both the high side fluid pressure and the lowsidefluid pres- sure existing in the air conditioning and refrigeration system that is being monitored, slide valve means being in fluid communication with each of the other three of said ports for controlling the flow of refrigerantto and from said passageway means from the air conditioning and refrigeration system that is being monitored and recharged, the three slide valves being substantially aligned and parallel with one another and extending downwardly from said manifold on one side thereof and with the gauge being located on the other side of said manifold op posite the valves and extending upwardly therefrom, and a hanger bracket connected at one end to the back of said gauge case and extending outwardly therefrom.

In a still further particularly ideal embodiment of the present invention there is provided an air conditioning and refrigeration system monitoring and refrigerant recharging device having a four-way manifold member including fluid flow passageway means therein for conducting refrigeranttoandfrom the air conditioning and refrigeration system, said passageway means terminating in at least fourflow ports, a single fluid flow pressure sensitive measuring gauge case in fluid communication with one of said ports and being capable of determining both the high side fluid pressure and the low side fluid pressure existing in the air conditioning and refrigeration system that is being monitored, slide valve means being in fluid communication with each ofthe other three of said ports for controlling the flow of refrigerantto and from said passageway means from the air conditioning and refrigeration system that is being monitored and recharged, the three slide valves being substantially aligned and parallel with one another and extending downwardlyfrom said manifold on onesidethereofand with the gauge being located on the other side of said manifold op posite the valves and extending upwardlytherefrom, and a hanger bracket connected at one endtothe back of said gauge case and extending outwardly therefrom, said hanger bracket including a substanti allyflat section arranged at substantially right angles to the rear ofthe gauge case and having a slidably mounted elongated shaft extending verticallytherethrough.

In yet another particularly ideal embodiment ofthe present invention there is provided an air conditioning and refrigeration system monitoring and refrigerant recharging device having a four-way manifold member including fluid flow passageway means therein for conducting refrigerant to and from the air conditioning and refrigeration system, said passageway means terminating in at leastfourfluid flow ports, a single fluid flow pressure sensitive measuring gauge case in fluid communication with one of said ports and being capable of determining both the high side fluid pressure and the low side fluid pressure existing in the air conditioning and refrigeration system that is being monitored, slide valve means being in fluid communication with each ofthe other three of said ports for controlling the flow of refrigerantto and from said passageway means from the air conditioning and refrigeration system that is being monitored and recharged, the three slide valves being substantially aligned and parallel with one another and extending downwardlyfrom said manifold on one sidethereof and with the gauge being located on the other side of said manifold opposite the valves and extending upwardly therefrom, a hanger bracket connected at one end to the back of said gauge case and extending outwardly therefrom, said hanger bracket including a substantially flat sec- tion arranged at substantially rightanglesto the rear ofthe gauge case and having a slidably mounted el ongated shaft extending vertically therethrough, a first stop member on the lower end of said shaftto limit the upward travel of the shaft and a second stop member adjacent the other upper end of said shaftto limit the downward travel ofthe shaft, and a hook formed in the upper end of the shaft above the second stop memberfor storing the device when it is not in use.

Instil another particularly ideal embodimentof the present invention there is provided an air conditioning and refrigeration system monitoring and refrigerant recharging device having a four-way manifold member including fluid flow passageway means therein for conducting refrigerant to and from the air conditioning and refrigeration system, said passageway means terminating in at leastfourfluid flow ports, a single fluid flow pressure sensitive measuring gauge case in fluid communication with one of said ports and being capable of determining both the high side fluid pressure and the low side fluid pressure existing in the air conditioning and refrigeration system that is being monitored, slide valve means being in fluid communication with each oftheotherthreeofsaid portsforcontrollingtheflow of refrigerant to and from said passageway means from the air conditioning and refrigeration system that is being monitored and recharged, the three slide valves being substantially aligned and parallel with one another and extending downwardly from said manifold on one side thereof and with the gauge being located on the other side of said manifold op positethe valves and extending upwardlytherefrom, a hanger bracket connected at one end to the back of said gauge case and extending outwardly therefrom, said hanger bracket including a substantiallyflat sec tion arranged atsubstantially rightanglesto the rear ofthe gauge case and having a slidably mounted elongated shaft extending vertically there through, a first stop member on the lower end of said shaftto limit the upward travel of the shaft and a second stop member adjacent the other upper end of said shaft to limit the downward travel ofthe shaft, a hook formed in the upper end of the shaft above the second stop memberfor storing the device when it is not in use, and a plurality of downwardly extending threaded male fittings arranged on the flat section of the bracket forthe storage of hose sections employed in servicing air conditioning and refrigeration systems.

Accordingly, it is a feature, object and advantage of the herein described and depicted present invention to provide a lighterweightand more compact single gauge air conditioning system monitoring andre- charging manifold device.

It is anotherfeature, object and advantage ofthe herein described and depicted presentinventionto provide an air-conditioning system monitoring and recharging manifold device wherein a third slide valve provides the new supply tank pressure readings when the other two slide valves are both closed.

It is also a feature, object and advantage ofthe herein described and depicted present invention to provide an air conditioning system monitoring and recharging manifold device which includes a hanger bracket provided with threaded male fittings to attach hoses when such hoses are not in use or connected to the air conditioning system.

It is also another feature, object and advantage of the herein described and depicted present invention to provide an air conditioning system monitoring and recharging manifold device which includes a slidable hook which renders the device compact when not in use.

It is a particular object ofthe present invention to provide apparatus for charging and monitoring low and high pressures in a temperature control system and the like, comprising measuring means responsive to low and high pressures, firstvalve means for selectively interconnecting and isolating said measuring means to and from said low pressures in said system, and second valve meansforselectively interconnecting and isolating said measuring means to and from said high pressure in said system.

It is also a particular object of the present invention to provide a subcombination apparatus, comprising a length offlexible conduit having provision atone end for interconnecting with a pressured supply of refrigerant and the like, and valve means inter connected atthe other end of said conduit and in- cluding a cylindrical body member having a first longitudinal passageway communicating with said con dust and extending to a first portatthesurface, and a second longitudinal passageway extending from the other end of said body member to a second port spaced at the surface from said first port therein, and a shutoff member slidably disposed on said body member and having an interior annular cavity spann- ing said first and second ports in the exterior ofthe body member.

These and otherfeatures, objects and advantages ofthe present invention will become apparentfrom the followed detailed description, wherein reference is made to the figures in the accompanying drawings.

In the drawings Figure lisa simplified functional representation of a conventional refrigeration system including a monitoring and recharging device ofthetype exemplary ofthe prior Figure2 is a similarfunctional representation of a refrigeration system including a monitoring and recharging device exemplifying the present invention.

Figure 3 is a simplified pictorial representation, partly in cross section, ofthe refrigeration system monitoring and refrigerant recharging device of Figure 2.

Figure4isasimplified pictorialsideviewrepre- sentation partly in cross section and partly in phantom of the air conditioning and refrigeration system monitoring and refrigerant recharging device of Figure 3.

Figures a simplified pictorial representation of a portion of the device of Figure 4 and taken along section line 5-5.

Figure 6is a simplified pictorial representation of one of the slide valves in Figure 3 shown in cross section and with the valve being illustrated in the closed position.

Figure 7is a simplified pictorial representation of the valve in Figure 6 and withthevalve being iliustra- ted in the open position.

Figure 8 is a view similarto Figure 6 but showing a modified form ofthe valve of the present invention.

Figure 9 is a top view of Figure 8 andtaken gener allyalongthesection line 9-9.

Figure 10 is a simplified pictorial representation of a heat pump installation, which embodies the concept ofthe present invention, and which is depicted in the cooling mode of operation.

Figure 11 is a simplified pictorial representation of the apparatus depicted in Figure 10, wherein the system is in the heating mode of operation.

Detailed description Referring now to Figure 1,there may be seen a simplified functional representation of the principal components of a typical compressor-type refrigeration system. More particularly, such a system will conventionally include a tank or other suitable reservoir 15 for holding a quantity of liquified refrigerant under a pressure, an exit conduit or line 90E for delivering an output flow of liquid refrigerant into the system, a pressure regulatororvalve30 and line 90Ffordelivering the refrigerant to the input of an evaporator unit 40 at a reduced pressure.

The evaporator unit 40, which may conventionally include or be composed ofatubular "coil" formed of a thermally conductive metal, preferably arranged to permit the in-coming refrigerant to vaporize as it passes through the evaporator unit 40. The effect of such vaporization, in turn, is to withdraw heat from air which flows over the exterior surfaces of the coil or unit 40. More particularly, a fan (not depicted) may be conveniently used to continually pass a stream of air across the exterior surfaces ofthe coil in the evaporator unit 40, whereby the ambient temperature of the interiorofthe dwelling will be reduced and maintained at a preselected temperature level.

Referring again to Figure lit will be apparent that the operating cycle ofthe system requires the vaporized refrigerantto be re-liquified after it leaves the evaporator unit 40. Accordingly, the vapor is prefer- ably conducted art a "low" pressure through line 90B to the input side of a suitable compressor unit 10, wherebythe pressure on the vapor is increased asit is discharged through line 90C, at a correspondingly highertemperature, to a suitable condenser unit 20 bywayofline90D.

Thefunction ofthe condenser unit 20 is to reliquify the hot refrigerant vapor being received from the compressor 10, and then to return this liquified refrigerantto the reservoir 15 by way of line 90A. Accordingly,the condenser unit 20may be ofanysuitable design, such as a coil of metallic tubing and the like, which is either immersed in a bath of a liquid coolant, orwhich may be subjected to a cooling flow of air blown across its exterior surfaces by means of a fan (not depicted) or other suitable means.Irrespective ofthe means selected, however, it will be apparent that the liquified refrigerant will bedischarged from the condenser unit 20, art a much lowertem perature from that which it had when it entered the condenser unit 20, but at substantially the same "high" pressure as that being maintained within the reservoir 15.

As herein before noted, it is inevitable that refrigerantwill tend to leak out of any system overa greater or lesser period oftime, and that the supply in the reservoir 15 must therefore be replenished or replaced at various intervals. On the other hand, it should also be noted that the system cannot operate effectively ifthere is any moisture within its component parts, and that before refrigerant can be introdu ced or reintroduced into the system, it must first be evacuated to remove all accumulated moisture.

Referring again to Figure 1, there may be seen a recharging device 50 which is interconnected to permit both evacuation and recharging ofthe system hereinbefore described, and which is depicted in U.S. Patent No.3,302,421. More particularly, there- charging device 50 may be interconnected by line 80B and a suitable shut-off valve 250 to accept and deliver refrigerantfrom a tank 25 into the system.

Referring specificallyto the recharging device 50 depicted in Figure 1, it may be noted that this device is composed of a body member having a longitudinal interior passageway, a pair of gauges 70A and 70B interconnected therewith, and three ports interconnected said passageway with lines 80A, 80B and 80C, respectively. In addition, the body member of this recharging device 50 will conventionally include a pairoffaucet-Iikevalves60Aand608.

When it is sought to evacuate the system depicted in Figure 1 ,the compressor 10 is first de-activated and thereafter whatever refrigerant then within the system is permitted to escape through suitable shutoff means (not depicted). The system is then reclosed, gauge 25A is closed, and both faucets 60A and 60B are opened whereby lines 80A, 80B, and 80C are all interconnected by means ofthe passageway within the body member of the device 50. Thereafter a suitable vacuum pump with micron gauge 25C may be activated to evacuate the system through line 80A-B and line 80C, and evacuation may be assumed to be complete when the reading exhibited on the micron gauge 25C reaches a preselected level.

After such evacuation, the refrigerant may be replenished in the system by de-activating the vacuum pump with micron gauge 25C, and also sealing off the vacuum pump from line 80D by suitable shut-off means not specifically depicted herein. Thereafter, valve 25A may be opened whereby refrigerant will flowfrom tank 25 through line 80B and the passageway in the device 50to lines 80Aand 800 within the system. It is conventional to permit the refrigerant to flow into and throughout the system until the pressure within the system, as indicated by the readings exhibited by gauges 70A and 70B, has equalized with respect to the pressu re within the new su pply tank 25.When this condition is achieved, it is further conventional to energize the compressor 10 and to close faucets 60A and 60B. Thereafter, the system will begin normal operation according to "true pressures" therein as indicated by the "high" pressure reading exhibited on gauge 70A and the "low" pressure reading exhibited on gauge 708.

If an additional amount of refrigerant is required forthe system, it will be apparent from the readings exhibited on gauges 70A and 70B, and the condition is easily corrected by opening valves 25A and 60B whereby refrigerant will flow into the system. When the gauges 70A and 70B exhibit the proper readings, however, valve 25A may be closed, and the pres sures within the system may be confirmed, as here- inbefore explained.

If both gauges 70A and 70B continue to indicate the proper high and low pressures for effectively operat- ing the system, the recharging device 50 may be removed from the system by means of suitable shutoff valves (not depicted) which may preferably be located at the junction of lines 90B and 90G, and also at thejunction oflines90C and 90B. If the reading on either or both gauges 70A and 708 tends to vary, however, this indicates a malfunction in the system which must be corrected before the system can be operated with confidence.

if the reading on the gauge 70B decreases while the reading on gauge 70A increases, this suggests that there is an obstruction in the low-pressure section of the system. To determine the location and thus the cause of such obstruction, it is necessary to disconnect line 80Afrom the output side of the evapora tor unit40, and then to reconnect line 80Ato line 90F.

Ifthe reading on the low pressure gauge 70B now rises, this suggests that the obstruction is located in or adjacent the evaporator unit 40. If the reading does not rise, however, then line 80C may be disconnected from the outputofthe compressor 10, and should be reconnected to line 90A. If the reading on the high pressure gauge 70A drops to any substantial extent, this indicatesthatthe obstruction is located in or adiacentthe condenser 20.

Itwill be apparent that this procedure may be used to locate defects in the system depicted in Figure 1.

However, it will also be apparent that it is timeconsuming and inconvenient to connect and disconnect these lines, and that it is accordingly timeconsuming and inconvenient to locate defects in this manner.

Figure 2 shows a system similarto that depicted in Figure 1 except that the system depicted in Figure 2 employs a monitoring and recharging device 100 embodying the present invention. More particularly, device 100 will be seen to include a single pressure gauge 101, and three slide valves 112-114. The particulars ofthe device 100 can be seen in more detail in Figures 3-5, but in all other respects, it will be noted thatthe system illustrated in Figure 2 is the same as the system depicted in Figure 1.

In Figure 3, the refrigeration system recharging device 100 will be seen to include a four-way manifold member 105, and a pair of elbow elements 106 and 107 establishingfourports 108,109,110, and 111.

Slide valves 112,113, and 114, are removably attached to manifold 105 and communicate respectivelywith each ofthe ports 109,110, and 111.

Into port 108 is connected, in detachable and removable fashion, a single pressure gauge 101 having a dial 103 and needle 104 as will hereinafter be explained in detail.

Referring again to Figure 3, itwill be seen that device 100 further includes a vertical shaft 115 is provided having a hook 116 at one end thereofforthe purpose of hanging the device 100 when not in use.

Thus, in Figures 4 and 5 there will be seen a hanger bracket 119 having a back section 121 attached to the rear of gauge case 102 buy a pair of connectors 122. A flat section 120 of bracket 119 houses a sleeve 123 through which shaft 115 is vertically movable as indicated by the arrow and by the section of shaft 115 shown in phantom. Flat section 120 also carries on its undersurface a plurality of threaded male fittings 124, 125, and 126, which fittings are used during storage ofthe device 100 as hose ends 80A, 80C, and 80D, are received thereon. Stop members 117 and 118 limit the upward and downward travel of the vertical shaft 115 in the annularsleeve 123.

Slide valves 112,113, and 1 14, are shown in detail in Figures 6 and 7, with Figure 6 illustrating the valve 1 14for example in its closed position whereas Figure 7 valve body member 127 threaded at both ends 142 and 143, and removably attached to port section 111 of elbow 107. An annular valve slide body member 135 is received on cylinder 127 and is movable be tween the lower stop ring 138 and an upperstopsurface 137 provided by a portion of port section 111.

Slide body 135 has a single o-ring seal 134therein below chamber 136 and a pair of o-ring seals 132 and 133 above the chamber 136. The valve cylinder body 127 includes a pair of elongated interiorflow passageways 128 and 129 spaced from and out of communication with one another. A port 130 extends radiallyfrom passage 128 whereas a port 131 extends radially from passage 129. As seen in Figure 6, port 130 is isolated from port 131 by during seals 132 and 133, whereas in Figure 7, ports 130 and 131 are in open flow relationship with respect to one another via chamber 136. Thus, the movement ofthe valve slide member 135 downwardly as seen in Figure6 closes the valve whereas movement of the valve slide member 135 upwardly as seen in Figure 7 opens the valve.

The embodiment of the valve shown in Figures 8-9 is substantially identical to that seen in Figure 6-7 and like numerals have been used to indicate like parts.

Figures 8-9 differfrom Figures 6-7 in that a separate upperstop ring 139 is provided instead of relying upon surface 137 of portsection 111. Further, each of ports 130 and 131 isprovidedwithanannularflow groove 140 and 141 respectively. Otherwise the construction and operation of the slide valves of Figures 6-9 is identical.

Referring again to Figure 1, it should be noted that the device 50 includes both a high side pressure gauge 70A and a lowsidepressuregauge70B,the purpose of which is to read the pressure on the high and low sides of the compressor 10 respectively.

However, valves 60A and 60B which control the flow to gauges 70A and 70B cannot be opened simultaneously otherwise the low side gauge 70B will be damaged when the pressure on the high side 80C is greaterthantheretard margin of the low side gauge 70B.

It should be noted that, whenever it is soughtto charge or recharge a system, it is essential thatthe system not be overcharged with refrigerant whereby there is insufficient space to permit vaporization.

Thus, the operator must continually monitor his gauge readings to interrupt refrigerant flow into the system at precisely the proper instant.

Whenever it is sought two use device 50 forthis purpose, however, it is extremely difficultto achieve such interruption within effective limits because of the nature of device 50 itself. More particularly, a faucet-type valve such as valves 60A and 60B are designed to achieve progressive ratherthan sharp cutoff, and especially when device 50 is being held and manipulated in one hand only.

Another limitation on the usefulness of a recharging device 50, is that whenever the operator is recharging the system from tank25 orthe like, the readings exhibited by gauge 70B will notbethetrue low pressure within the system, but instead will cor respond to the discharge pressure between valve 25A and the device 50. Accordingly, whenever it is necessary or desirable for the operatorto verify the true or actual low pressure within the system, the operator must first rotate the faucet valve 60B until it is fully closed, before he can determine the pressure from the reading on gauge70B.

Similarly,iftheoperatorwishesto readthepres- sure within tank 25, h e m u he mustfirstdisconnect hose or line 80Afrom the body memberofthe device 5, and he mustthen close the correspond portwith a cap or plug (not depicted) before reopening faucet valve 60B to connecttank 25to the low pressure gauge 70B.

Referring again to Figure 2, it will be noted that only a single pressure gauge 101 is provided with the recharging device 100. However, it should also be noted that gauge 101 is selected to measure negative pressures below zero, as well as positive pressures upto the same limit as gauge 70A in Figure 1.

Accordingly, there is no need with device 100 to be concerned about exposing the "low" pressure gauge to the "high" pressure side of the system . In Figure2 there is also employed slide-type valves 112-114, which provide for instantaneous shut off to eliminate or greatly reduce the chances of overcharging the system. Furthermore device 100 in Figure 2 is designed and intended to be held and operated with one hand only, duetothe parallel alignmentofthevalves 112-1 as seen more clearly in Figure 3, for example.

Such valves render low side system checks easier and quickerto make, and such low side system checks can be achieved without the need to disconnect any of the hoses 80A-80C, because the operatop can merely close the low side slide valve 112 with a quickflip of his thumb. In this regard it should further be noted that valve 60B in Figure 1 does not open or close line 80A, but merely connects or disconnects tank 25 from the low side 90B and 90G of the system, and also from gauge 70B. In Figure 2, however, slide valve 112 opens or closes the low side 80A of the system, to or from tank 25, as well as from gauge 101, provided valve 113 is also open at the same time.

Whenever a leak occurs in the system depicted in Figures 1 and 2, and wheneverthe system is being initially installed and/orchargedforthefirsttime, it is required to evacuate the system to remove moisture and atmospheric gases as hereinbefore explained. If device 50 is used forthis purpose, the line 80B has to be disconnected and then connected to a vacuum pump, the vacuum pump must then be turned on, and valves 60A and 60B are both then opened. However, neither of gauges 70A and 70B is accu rate to indicate when the correct vacuum is reached, and this is why such reading must be taken from a sep arate micron gauge.On the other hand, it is only requires to close slide valve 112 and evacuate through slide valve 1 14for an interval, whenever device 100 is employedforthis purpose. Slide valves 113 and 114 are then both closed and slide valve 112 is opened. If gauge 101 changes its reading, it can only be because a stoppage has isolated the low side 80A ofthe system from the pump during evacuation and only the high side 80C of the system has been actually pumped out. This cannot be done in Figure 1 because gauges 70A and 70B are calibrated differently and will read different from each other.

Referring now to Figure 10, there may be seen a simplified pictorial representation of a heat pump installation, which also employs the concept ofthe present invention, and which may conveniently include a reservoirortank 150 for accumulating and retaining liquid refrigerant 151 which would otherwise flow into the compressor 170. Accordingly, the liquid refrigerant 151 preferably vaporizes to exit the tank 150 byway of an outlet line 171 leading to a service valve 172 inthecompressor170.

The compressor 170, in turn, discharges hotgaseous refrigerant from its other service valve 174, through line 173 to the reversing valve 154 when, if its slide 155 is positioned as illustrated in Figure 10, will routethevaporized refrigerantthrough line 175 to the coil 181 which, in this mode, acts as a con- densor. Accordingly, refrigerant exiting the coil 171 will depart in liquid form to and through the check valve 185.

Referring again to Figure 10, it will be noted that the output side of the coil 181 is also connected to one side of a thermostatic expansion valve 187 which, in turn, is controlled by an appropriate signal received through conductor 188 from a temperature sensor 186 mounted on line 175 atthe inlet side ofthe coil 181.

When the system is in the cooling mode, as illustrated in Figure 10,thevalve 187 may be eitherclosed or partially open. However, the refrigerant exiting the coil 181 will tend tofollowthe line of least resistance by passing through the check valve 185. On the other hand, any refrigerant which does leakthrough the ex pansion valve 187, and through line 182 and the filteri drier 183, will be comingled with refrigerantflowing fromthecheckvalve 185through lines 168 and 166, to line 165 and anotherfilter/drier 161.

It will be noted that refrigerant passing into line 166 is preferably liquid in form, and this may be confirmed with asuitablevisual indicator 167 mostconveniently located at the junction between lines 166 and 168. Inasmuch asthecheckvalve 159 is arranged to refusepassageto refrigerantwithin line 165 all re frigerantflowing through line 166 will flow into and through thefilter1drier 161 and line 160 to another thermostatic expansion valve 163 interconnected to a temperature sensor 162 by a suitable conductor 164.

In this mode, the expansion valve 163 is open to pass liquid refrigerant (which was cooled during its travel through the coil 181) into and through the coil 157, to line 156 leading into the reversing valve 154.

However, the refrigerant absorbs heat from air flow ing overthe exterior surfaces ofthe coil 157 atatem- perature sufficiently high enough to cause the sensor 162 to generate a sig nal appropriate to keep the ex- pansion valve 163 in its open state.In this regard, it should be noted that the expansion valve 163 opens or closes to an extentdependentuponthetem- perature of the refrigerant in line 156. lfthetem- perature ofthe air passing over the coil 157 is not great enough to supply adequate heat to the re frigerantinthe coil 157, the valve 163 will close to an extent sufficient to restrict and retard the refrigerant to a flow rate which will permitthe refrigerantto ob- tain a sufficient amount of heatfrom the air.

When the reversing valve 154 is in the condition illustrated in Figure 10, refrigerantwillflowfromthe reversing valve 154,to and through thefilter/drier 153 and line 152, backto the reservoirtank 150. Once in the tank 150, however, the cycle is then repeated as herein before described.

Referring again to Figure 10, it should be noted that a recharging device 176 ofthe same design as the device 100 depicted in Figures 2 and 3, may be included for the purpose of evacuating and recharging this system with refrigerant obtained from a resupply tank 180. In this arrangement, the tank 180 and recharging device 176 are interconnected by line 179, the "low" pressure side of the device 176 is connected by line 178 with the service valve 172 in the compressor 170, and the "high" pressure side of the device 176 is coupled through line 177 to the otherservice valve 174 in the compressor 170.

Whenever it is sought to transfer refrigerant from the resupplytank 180, all three slide valves on the recharging device may be opened, if the compressor 170 is not in operation, until the pressure reading on the gauge ofthe recharging device 176 stabilizes at a preselected level. To confirm that this reading corresponds to the true system pressure, the operator will close the slide valves interconnected with lines 177 and 178. Alternatively, to confirm thatthe readingonthegaugecorrespondstothetrue"high" pressure in the system, the operator will close the slide valve connected with line 178 and open the slide valve connected with line 177. Stoppages within the system may, ofcourse, be confirmed and located in a similar manner.

Referring now to Figure 11, there may be seen the same system depicted in Figure 10 butwhereinthe reversing valve 154 has been repositioned to putthe system into its "heating mode". In particular,the slide 155 in the reversing valve 154 now routes hot refrigerantvaporfrom the compressor 173 through line 156to the coil 157 in orderto supply heatto air flowing over the exterior ofthe coil 157. It should be noted, however, that although the refrigeranttends to flow in an "opposite" direction through the system, the recharging device 176 is interconnected with the compressor 170 in the same manner as before.

Referring again tothe structures depicted gener- ally in Figures 10 and 11, it should be particularly noted that it is not always practical to effect an interconnection of the recharging device 176, with the compressor 170, in the manner as indicated. This is because, in many forms ofthe compressor 170, the service valves 172 and 174 are housed or enclosed in a manner whereby access cannot be achieved without substantially disassembling the equipment.

It should further be noted, however, that even in those heat pump systems wherein access to the in terior of the compressor 170 is impractical or incon- venient, the functional results may be achieved by interconnecting the "high pressure" side of therecharging device 176 between line 156 and the reversing valve 154, when the system is in the cooling mode, andthe "low pressure" side ofthe recharging device 176 is then connected with or between line 175 and the reversing valve 154.

It will be apparent that, when the slide 155 in the reversing valve 154 is shifted to change the system to the heating mode, the so-called "low pressure" side ofthe recharging device 176 now becomes the "high pressure" side and the so-called "high pressure" side of the recharging device 176 becomes its "low pressure" side. If the prior art recharging device 50 is incorporated in the depicted heat pump system, in place ofthe recharging device 176 now illustrated in Figures 10 and 11, this will shift high pressure in the system to the low pressure gauge 70B and low system pressure onto the high pressure gauge 70A.

In some arrangements,thecompressor170 is not only inaccessible to service personnel, a substantial portion ofthe heat pump system including the reversing valve 154, line 175, and the entire coil 181,as well as the compressor 170, may all be enclosed in a housing which cannot easily or conveniently be opened. In such a circumstance, one "side" of the recharging device 176 may still be interconnected in or between line 156 and the coil 157, and the other "side" may be connected at some suitable location along line 184, without departing from or sacrifice of any of the advantages of the present invention.

As previously explained with regard to Figure 2, the recharging device 176 depicted in Figures 10 and 11 employs only one gauge or registration means which is capable of providing pressure indications over the entire gamut of operating parameters for a heat pump system ofthis type. Under these circumstances, it is immaterial to the operation of the sub- ject recharging device 176 whether the depicted heat pump system isin a heating ora cooling modeforthe purposes of the present invention.

Referring again to Figures 6-9, it should be noted thatsuch a valve is notonly particularlysuitable as a component in the recharging devices 100 and 176 depicted in Figures 2-5 and 10-11 herein, this type of valve is also especially useful for interconnecting components such as lines 80A-D to the system illustrated in Figure 2. In particular, a slide valve ofthis design may suitably be installed at points such as the junction between lines 90B and 90G, whereby line 80A may be provided in the form of a flexible hose or the like which is removably connectable between the valve and the "low pressure" valve 112 depicted in Figure 2. Alternatively, the valve may be interconnected as an integral part of hose or line 80A and suitable connector means (not depicted) may be installed in the system for releasably mating with the valve.

Referring again to the slide-type valve depicted in Figures 6-9, itshould be noted that a particular advantage ofthis type of component is the fact that, in contractwith the faucet-type valves 60A-B in Figure 1, such a valve achieves a relatively instantaneous cut-off with only a minimum of exertion on the part ofthe operator of this equipment. However, this advantage is dependent upon easy movementofthe slide body 135 relative to the valve body member 127.

Accordingly, itis desirableto provide an oil film or other suitable lubricant between the abutting sur faces ofthe slide body 135 and the body member 127.

ltshould be noted, however, that when a valve of this design is installed to control theflowofa re- frigerant and the like, there is a tendencyforthe refrigerantto dissolve or flush outthe lubricant from these surfaces and this is especially true where the valve is located where it remains in either an "open" or a "closed" state for any significant period oftime.

Wheneverthissituation exists or occurs,the slide body 135 then becomes extremely difficultto move in eitherdirection along the valve body member 127.

The situation can be alleviated bysnappingthesldie body 135 back and forth several times, whereby the o-rings 132-134will tend to smear or otherwise redistribute the remaining lubricant along the affected surfaces of the slide body 135 and the valve body member 127, and this may be practical insofarasthe valves 112-114are concerned which are components ofthe recharging device 100 depicted in Figure 2 herein. As to those valves which are sought to be used in other locations within the system, however, it may not be convenient ordesirableto movetheslide body 135 except as determined by the operating requirements ofthe system.

This disadvantage may be effectively reduced or eliminated by providing means for relubricating the affected portion or surface ofthe body member 137 whereby no special effort is required to "start" the slide body 135 regardless of how long this component has been immobilized. More particularly, one or more ring-like components which are formed of a suitably absorbent material, and which are impregnated with a lubricant, may conveniently be provided within respective recesses in the slide body 135 at appropriate locations adjacent the o-ring 132-134, to achieve this benefit without adversely affecting or otherwise sacrificing any ofthe other advantages of the present invention.

The preferred single gauge unit ofthe present invention is Model No.19792 manufactured by MAR SHALLTOWN INSTRUMENT COMPANY, Marshalltown, Pennsylvania, and having a range of thirty inches of vacuum to five hundred pounds per square inch, although other equivalent gauges may be employed if desired. It is contemplated to also employ an electronic gauge as an alternative and including preferably a transducer, logic circuit, and LCD display. A digital read-out device may be employed in place ofthe pressure gauge and in such an instance it has been contemplated to employ a digital computer ofthe type manufactured by WALLACE AND TI ER- MAN, a division of PEN NWALT CORP., Belleville, N.J., and a digital pressure gauge SERIES 66-100 having a 4-20 milliamp output.

As herein before noted, the registration means, which may be employed in the recharging device 176, may be a gauge 101 such as that depicted in Figures 3 and 4 herein, or it may be an electronic LCDtype unit as hereinbefore described. In eitherarrangement, it should be particularly notedthatthe recharging device 176 is particularly useful as a trouble analyzer to detect and locate stoppages in the refrigeration or heat pump systems illustrated in Figures 1-2 and 10-11 herein.

It should be noted that the prior art recharging de vice 50, which is depicted in Figure 1, can be em plowed to determine the existence of a stoppage in the system in the same manner. It should also be noted, however, that it is far more difficult and incon venientto use the recharging device 50to actually locate the obstruction which has caused the stoppage, than to use the subject recharging device 176forthis purpose. More particularly, the ideal pro cedureto use in finding the obstruction, is to first re move line 80Afrom line 90D, and to reconnect line 80A to line 90F. If the reading exhibited remains the same, then it can be assumed thatthere is no ob struction in or at the coil 40.

Referring again to Figure 2, the presence of a stoppage in the system may be immediately detec ted by merely closing valves 112 and 114, and also closing valve 113, while at the same time energizing the compressor 10. If the low pressure reading on the gauge 101 declines when the low pressure valve 112 is thereafter opened, this clearly indicates a stoppage in the system. When valve 112 is closed, and valve 114 is opened, the pressure reading exhibited on gauge 101 will rise above the normal system operat ing level to clearly indicate the existence of a stoppage in the system.

If the obstruction has not been located by this first step, then line80Cshould be disconnected from line 90D, and be reconnected to line 90E to isolate valve 30. if same low reading continuesto beexhibited, then it is apparent that the obstruction must line up stream in the system. Accordingly, line 80C should be removed and reconnected to line 90A, to isolate the reservoirtank 15 from the system. If the same low reading continues to exist, the obstruction obviously lies in eitherthe condenser 20 or in line 90A.

It will be apparent that it is burdensomely time con- suming,to be required to cut into a metallic line merely to perform the foregoing diagnosis of the system. This is why it is extremely desirable to provide slide valves as designed in Figures 5-9 at each of these particular locations in the system,together with appropriate connector means (not depicted).

However, it will alsobe apparent from the foregoing explanation, that it is even more desirable to provide lines 80A-80C andthe like, in aformcomposed ofa flexible hose with a valve of this type coupled at one end thereof.

Although the recharging devices and their associated component can be arranged and adapted to be only temporarily described, it should be understood that parts or all of such apparatus can also be advan tageously made a permanent part of these types of systems. In particular, if these components are per manently installed, they can obviously be located in a mannerto make them moreaccessibletotheoper- ator, and thus more convenientto use forth purposes herein before described.

For example, if the recharging device 100 in Figure 2, is properly built into the system, it may be permissable to completely dispense with the auxiliary valve 25A, or it may be acceptableto instead employ the shutoff valve (not depicted) which is usually found on top ofthetank 25. In anotherpossiblearran- gement, the recharging device 100 and lines 80A-D may be mounted on top of and made a parts a port able version of the tank 25, ratherthan making these components into either a separate assembly or an integral partofthesystem.

Itwill be apparentfrom theforegoing that many other variations and modifications may be made in the structures and methods described herein without departing substantially from the essential concept of the present invention. Accordingly, it should be clearly understood that the forms of the invention described herein and depicted in the accompanying drawings, are exemplary only, and are not intended as limitations on the scope ofthe present invention.

Claims (29)

1. Apparatusforcharging and monitoring low and high pressure in a temperature control system and the like, comprising measuring means responsive to low and high pressures, first valve means for selectively interconnecting and isolating said measuring means to and from said low pressures in said system, and second valve means for selectively interconnect- ing and isolating said measuring means to and from said high pressures in said system.

2. The apparatus described in claim 1, wherein said first valve means further selectively inter connects and isolates said second valve means to and from said low pressures in said system.

3. The apparatus described in claim 2, wherein said second valve means further selectively interconnects and isolates said first valve means to and from said high pressures in said system.

4. The apparatus described in claim 3,further comprising third valve means interconnected with said measuring means and selectively openable outwardly of said system.

5. The apparatus described in claim 4, wherein saidthirdvalvemeansisfurtherinterconnectable with a supply of pressurized refrigerant and the like.

6. The apparatus described in claim 5, wherein said valve means are each comprised of a cylindrical body member having a first long itudinal passageway extending partially therethrough from one end, a second longitudinal pas sagewayextending partiallytherethroughfromthe other end, a first radial passageway extending from the exteriorsurfaceto said first longitudinal passageway therein, and a second radial passageway exten ding from the exterior surface to said second long itudinal passagewaytherein and spaced from said first radial passageway, and a cylindrical shutoff member slidably disposed on said bodymemberand having an annular interior cavity portion for extending across said first and second radial passageways, and stop means located adjacent said one end of said bodymemberforlimiting slidabletravel of said shutoff member toward said one end thereof.

7. The valve means described in claim 6, wherein said shutoff member is further adapted to block com- munication between said radial passagewayswhen said shutoff member slidably moves to said stop means.

8. The valve means described in claim 7, wherein said shutoff member is also adapted to open communication between said radial passageways in said body memberwhen said shutoff member slidably moves from said stop means to the other end of said body member.

9. The valve means described in claim 8, wherein said annular interior cavity is located within and to ward the end of said shutoff member adjacent said stop member.

10. The valve means described in claim 9, further comprising means for distributing lubricant between abutting surfaces of said body member and said shutoff member.

11. In a subcombination, apparatus comprising a length offlexible conduit having provision atone end for interconnecting with a pressured supply of refrigerant and the like, and valve means interconnected at the other end of said conduit and including a cylindrical body member having a first longitudinal passageway communicating with said conduit and extending to a first port atthe surface, and a second longitudinal passageway extending from the other end of said body member to a second port spaced at the surface from said first port therein, and a shutoff member slidably disposed on said body member and having an interiorannularcavityspanning said first and second ports in the exterior of said body member.

12. Thesubcombination described in claim 11, wherein said body memberfurther includes prov isionforlimitingtravel ofsaidshutoffmemberinone direction along said body member.

13. The subcombination described in claim 12, wherein said annular cavity is located proximate one end of said shutoff member.

14. Thesubcombination described in claim 13, wherein said shutoff member is further adapted to open communication between said ports in said body memberwhen said shutoffmember is positioned at one location along said body member and to block communication between said ports when said shutoff member is positioned at anotherdif- ferent location along said body member.

15. Thesubcombination described in claim 14, further comprising means for distributing lubricant between abutting surfaces of said body member and shutoff member.

16. An air conditioning and refrigeration system monitoring and refrigerant recharging device comprising a manifold having passageway means therein terminating in at leastfour ports, a single pressure gauge in fluid communication with one of said ports and being capable of measuring both the high side pressure and the low side pressure in the air conditioning and refrigeration system being monitored, and valve means in fluid communication with each ofthe other ports for controlling the flow offluid to and from said passageway means.

17. An air conditioning and refrigeration system monitoring and refrigerant recharging device comprising a four-way manifold having passageway means therein terminating in at least four ports, a single pressure gauge in fluid communication with one of said ports and being capable of measuring both the high side fluid pressure and the low side fluid pressure in the air conditioning and refrigeration system being monitored, and slide valve means in fluid communication with each ofthe otherthree portsforcontrolling the flow of fluid to and from said passageway means.

18. An air conditioning and refrigeration system monitoring and refrigerant recharging device comprising a four-way manifold member including fluid flow passageway means therein for conducting refrigerantto and from the air conditioning and refrigeration system, said passageway means ter minating in at least fourfluid flow ports, a singlefluid flow pressure sensitive measuring gauge in fluid communication with one of said ports and being capable of determining both the high side fluid pressure and the low side fluid pressure existing in the air conditioning and refrigeration system that is being monitored, and slide valve means being in fluid communication with each of the otherthree of said ports forcontrolling theflow ofrefrigerantto and from said passageway means from the air conditioning and refrigeration system that is being monitored and recharged

19. Avalvecomprising an elongated cylindrical body member having a first axially extending pas sagewaytherein open at one end and closed and terminating within the interior ofthe body cylinder at the other end, a second axially extending passageway in the cylinder body and being open at one end and closed and terminating within the interior ofthe body member at the other end, the passageways being separated one from the other at their closed ends, a first and a second radially extending port in said body member with one port being in fluid com munication with the closed end of one ofthe passageways and the other port being in fluid com munication with the closed end ofthe other passageway, an annularslide member in surrounding re lationship to a portion ofthe body member and hav ing a single o-ring at one end and a pair of spaced o-rings at the other end, said slide member including a chambertherein between said single o-ring and said pair of spaced o-rings,wherebywhen said slide member is in a first location on the body memberthe chamber provides fluid communication between the ports whereas when said slide member is in a second location on the body memberthe ports are isolated one from the other.

20. Avalve in accordance with claim 4 and includ ing at least one stop member on said body cylinder adjacent one end thereof.

21. Avalveinaccordancewithclaim 5and includ ing a second stop member on said body member adjacent the other end thereof, said slide member being received on the body member between the stop members.

22. A valve in accordance with claim 6 and wherein the body member cylinder includes a pair of annular grooves in its outer surface, each port being in communication with one of said grooves.

23. An airconditioning and refrigeration system monitoring and refrigerant recharging device com prising a four-way manifold member including fluid flow passageway means therein for conducting refrigerantto and from the air conditioning and refrigeration system, said passageway meansterminating in at leastfourfluidflow ports, a singlefluid flow pressure sensitive measuring gauge in fluid communication with one of said ports and being capable of determining both the high side fluid pressure and the low side fluid pressure existing in the air conditioning and refrigeration system that is being monitored, slide valve means being in fluid communication with each of the otherthree of said ports for con trolling the flow of refrigerantto and from said pas- sagewaymeansfromthe airconditioning and re- frigeration system that is being monitored and recharged, the three slide valves being substantially aligned and parallel with one another and extending downwardly from said manifold on one side thereof and with the gauge being located on the other side of said manifold oppositethevalvesand extending upwardlytherefrom.

24. An air conditioning and refrigeration system monitoring and refrigerant recharging device comprising a four-way manifold member including fluid flow passageway means therein for conducting refrigerantto and from the air conditioning and refrigeration system, said passageway meansterminating in at least fourfluid flow ports, a singlefluid flow pressure sensitive measuring gauge case in fluid communication with one of said ports and being capable of determining both the high side fluid pressure and the low side fluid pressure existing in the air conditioning and refrigeration system that is being monitored, and slide valve means being in fluid communication with each of the otherthree of said ports for controlling theflow of refrigerantto and from said passageway means from the air conditioning and refrigeration system that is being monitored and recharged, the three slide valves being substantially aligned and parallel with one another and extending downwardly from said manifold on one side thereof and with the gauge being located on the other side of said manifold opposite the valves and extending upwardlytherefrom, and a hanger bracket connected at one end to the back of said gauge case and extending outwardly therefrom.

25. An air conditioning and refrigeration system monitoring and refrigerant recharging device comprising afour-waymanifold member including fluid flow passageway means therein for conducting re frigeranttoandfromtheairconditioning and refrigeration system, said passageway means terminating in at leastfourfluid flow ports, a singlefluid flow pressure sensitive measuring gauge case in fluid communication with one of said ports and being capable of determining both the high side fluid pressure and the low side fluid pressure existing in the air conditioning and refrigeration system that is being monitored, and slide valve means being in fluid communication with each ofthe otherthree of said ports for controlling the flow of refrigerant to and from said passageway means from the air conditioning and refrigeration system that is being monitored and recharged, the three slide valves being substantially aligned and parallel with one another and extending downwardly from said manifold on one side thereof and with the gauge being located on the other side of said manifold opposite the valves and extending upwardlytherefrom, a hanger bracket connected at one end to the back of said gauge case and extending outwardly therefrom, said hanger bracket including a substantially flat section arran- ged at substantially right angles to the rear of the gauge case and having a slidably mounted elongated shaft extending vertically therethrough.

26. An air conditioning and refrigeration system monitoring and refrigerant recharging device comprising a four-way manifold member including fluid flow passageway means therein for conducting re frigeranttoandfromtheairconditioningand re- frigeration system, said passageway meansterminating in at leastfourfluid flow ports, a singlefluid flow pressure sensitive measuring gauge case in fluid communication with one of said ports and being capable of determining both the high sidefluid pressure and the low side fluid pressure existing in the air conditioning and refrigeration system that is being monitored, slidevalve means being in fluid communication with each ofthe other three ofsaid ports for controlling the flow of refrigerant to and from said passageway means from the air conditioning and refrigeration system that is being monitored and recharged, the three slide valves being substantiallyaligned and parallel with one another and extending downwardlyfrom said manifold on one side thereof and with the gauge being located on the other side of said manifold opposite the valves and extending upwardlytherefrom, a hanger bracket connected at one end to the back of said gauge case and extending outwardly therefrom, said hanger bracket including a substantially flat section arran- ged at substa ntially right a ng les to the rear of the gauge case and having a slidably mounted elongated shaft extending vertically therethrough, a first stop member on the lower end of said shaftto limitthe upward travel ofthe shaft and a second stop member adjacentthe upper end of said shaftto limitthe downward travel of the shaft, and a hook formed in the upper end of the shaft above the second stop member for storing the device when it is not in use.

27. An air conditioning and refrigeration system monitoring and refrigerant recharging device comprising afour-waymanifold member including fluid flow passageway means therein for conducting refrigerantto and from the air conditioning and refrigeration system, said passageway meanster minating in at least fourfluid flow ports, a single fluid flow pressure sensitive measuring gauge case in fluid communication with one of said ports and being capable of determining both the high sidefluid pressure and the low side fluid pressure existing in the air conditioning and refrigeration system that is being monitored, slide valve means being in fluid communication with each of the otherthree of said portsfor controlling the flowof refrigerantto and from said passageway means from the air conditioning and refrigeration system that is being monitored and recharged, the three slide valves being substantiallyalignedand parallel with one anotherand extending downwardly from said manifold on one side thereof and with the gauge being located on the other side of said manifold opposite the valves and extending upwardly therefrom, a hanger bracket connected atone end tothe backofsaidgaugecase and extending outwardly therefrom, said hanger bracket including a substantially fl at section arranged at substantially right angles to the rear of the gauge case and having a slidably mounted elongated shaft extending verticallytherethrough, a first stop member on the lower end of said shaft to limitthe upward travel ofthe shaft and a second stop member adjacentthe upper end of said shaft to limitthe downward travel of the shaft, a hook formed in the upper end of the shaft above the second stop member for storing the device when it is not in use, and a plurality of downwardly extending threaded malefittingsarrangedontheflatsection ofthe bracketforthe storage of hose sections employed in servicing air conditioning and refrigeration systems.

28. A system substantially as herein described with reference to any of Figures 2 to 9 of the accompanying drawings.

29. An installation substantially as herein described with reference to Figures 10 and 11 of the accompanying drawings.