Can Tapper With Explosion Preventing Means

Abstract

An apparatus for transferring pressurized fluid from a first fluid container to a second fluid container with means for preventing explosion of the first container as a result of high pressure therein. The first container illustratively comprises a can of pressurized fluid and the transferring apparatus illustratively comprises a can tapper arranged to pierce a pierceable portion of the can, and having valve means for controlling the flow of the pressurized fluid from the pierced can to the second container. Means are associated with the can tapper for causing a cooling of the can by directing fluid against the can as an incident of the pressure of the fluid in the can rising above a preselected abnormally high level. The can tapper includes means for limiting the fluid pressure in the pierced can to a preselected maximum pressure at all times irrespective of the open or closed condition of the control valve.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to fluid transferring apparatus and in particular to can tappers.

2. Description of the Prior Art

In George E. Franck U.S. Letters Patent Nos. 2,893,603 and 3,092,291, owned by the assignee hereof, can tapping devices are illustrated for transferring fluid from a container of fluid under pressure to a receiver, such as another container, a piping system, etc. In one form of such device, the pressurized fluid container comprises a can of refrigerant fluid under pressure with the can tapping device being arranged to pierce the top of the refrigerant can and permit flow of the pressurized fluid into a refrigeration system such as for charging the system.

It has been found that, at times, the person transferring the fluid by means of such a can tapper has been seriously injured as by an explosion of the can while the user is handling it. Such explosions may occur, for example, where the user improperly heats the can in order to expedite the flow of the fluid therefrom. Alternatively, at times, the refrigerant system may have an abnormally high pressure condition therein which, when the valve is opened between the refrigerant system and the connected refrigerant can, causes an abnormally high condition to also then be present in the can which may resultingly explode. Illustratively, it is suggested by the refrigerant suppliers that the cans be heated only by heating them with warm water. However, at times, the user may use water heated to above the recommended temperature or even may direct a blowtorch, or the like, against the can so as to present a highly dangerous explosion-tending condition.

SUMMARY OF THE INVENTION

The present invention comprehends an improved can tapping device adapted to not only provide for controlled connection between a container of fluid under pressure and a receiver, but also to limit the fluid pressure in the container to effectively preclude injury to the user as by explosion or similar rupture of the container as may result from a high pressure condition therein. The invention comprehends such an apparatus for transferring pressurized fluid wherein the pressure limiting means not only limits the pressure of the fluid in the container when the valve is closed, but also functions to limit the pressure of fluid in the container when the valve is opened to protect the user against a high pressure condition which might arise in the container by a backflow of high pressure fluid from the system being charged, such as where the system has an abnormally high pressure condition therein.

Further, the invention comprehends providing means for automatically tending to cool the container as an incident of a high pressure condition existing therein so as to tend to lower the pressure in the container and thereby alleviate the dangerous condition. More specifically, the invention comprehends providing means in association with the fluid transferring apparatus which functions to direct fluid from the container against the outside of the container as an incident of a high pressure condition therein thereby tending to cool the container and resultingly lower the pressure therein. The fluid directing means may comprise means associated with the pressure relief means discussed above so that the pressure condition in the container may be alleviated both by discharging a portion of the fluid from the container to lower the pressure of the fluid therein and to cause a cooling of the container to further lower the pressure therein.

The apparatus may include a manually operable control valve which may selectively carry the pressure relief means or which may extend through the flow passage of the transferring apparatus to be independent of the flow path of the pressure relief means. The apparatus is arranged so that the pressure relief means is in communication with the container at all times whether the valve is opened or closed and, thus, provides pressure relief of the container immediately upon connection of the fluid transferring apparatus such as by piercing the container where the fluid transferring apparatus comprises a conventional can tapping piercing means .

BRIEF DESCRIPTION OF THE DRAWING

Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein:

FIG. 1 is a vertical section of a fluid transferring apparatus embodying the invention as installed on a pressurized fluid container;

FIG. 2 is an enlarged fragmentary transverse section taken substantially along the line 2--2 of FIG. 1;

FIG. 3 is a transverse section taken substantially along the line 3--3 of FIG. 1;

FIG. 4 is an end view of the fluid transferring apparatus positioned for connection to the fluid receiver;

FIG. 5 is a vertical section of a modified form of fluid transferring apparatus embodying the invention; and

FIG. 6 is a transverse section taken substantially along the line 6--6 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the exemplary embodiment of the invention as shown in FIGS. 1-4 of the drawing, a fluid transferring apparatus generally designated 10 illustratively comprises a can tapper for use in transferring a pressurized fluid, such as Freon refrigerant fluid, from a can 11 of conventional construction. Thus, the can 11 includes a pierceable top, or cover, 12 adapted to be pierced by a piercing needle 13 carried by the body 14 of the can tapper. The can tapper includes a gripping portion 15 adapted to engage an upper flange 16 of the can 11. The body 14 and gripper 15 define cooperating threads 17 permitting the piercing element 13 to be forced through the pierceable cover 12 as an incident of turning of the can tapper body 14 on the gripper 15 until the piercing element pierces the cover and is sealed thereto by a suitable annular seal 18 carried by the body surrounding the piercing element 13.

The can tapper body further defines a flow passage generally designated 19 having a first portion 29 communicating through the tubular piercing element 13 with the interior of the can 11 upon piercing of the cover 12 as discussed above. The body 14 further defines a connector portion 21 having a suitable external thread 22 and internally defining an outlet flow passage 23 for fluid transfer connection to a suitable receiver such as a refrigerant system schematically shown at 24.

Flow of fluid from container 11 to receiver 24 is controlled in the can tapper 10 by means of a suitable valve generally designated 25 having a movable valve element 26 movably disposed in a third flow passage portion 27 extending between flow passage portions 20 and 23, respectively.

Movable valve element 26 selectively engages a valve seat 28 at the inner end of outlet flow passage portion 23 for closing the flow passage 19 thereat when desired while leaving the flow passage 19 open to a relief chamber 29 in a relief valve portion 30 of body 14. The valve member 26 is movably positioned by the mounting thereof on a valve stem 31 having a threaded inner portion 32 threadedly engaging an internal thread 33 in body 14. The valve stem 31 is rotated by a suitable handle 34 secured to the outer end thereof with the valve stem being rotatably sealed to the valve body 14 by a seal ring 35 and cup-shaped cap 36 threaded to an outer thread 37 on the valve body concentrically of the internal thread 33.

Valve stem 31 is undercut at 38 to provide the desired communication between relief valve chamber 29 and flow passage portion 20 at all times. A pressure relief valve 39 is mounted in a tubular housing 40 having a lower threaded end 41 threaded into an internal threaded portion 42 of relief valve portion 30 at the outer end of chamber 29. Valve mechanism 39 functions to discharge pressurized fluid outwardly through an outer end 43 of the housing 40 when the pressure reaches a preselected maximum. A cover 44 is secured to the body portion 30 by suitable means such as screws 45 to prevent the discharged high pressure fluid from flowing directly outwardly from the relief valve mechanism, and turns the fluid back downwardly to flow out through the lower open end 46 of the cover. The cover end 46 opens toward the valve body 14 and container 11 so as to direct the relief high pressure fluid downwardly thereagainst and as a result of the flow of this fluid thereagainst, tends to cause a cooling thereof. The cooling of the container 11 effects a lowering of the fluid pressure therein and, thus, the discharge of the high pressure fluid through the relief valve structure generally designated 47 causes a lowering of the pressure in container 11 not only by virtue of the release of some of the pressurized fluid, but also by the cooling effect on the container.

As indicated above, at times the connection of the container 11 of the receiver 24 may present a hazardous condition as where the fluid in chamber 24 is at abnormally high pressure, such as may cause rupture of the container 11. To prevent this pressure from being applied to the container 11, a ball check 48 is provided in outlet flow passage 23 to seat on a frustoconical seat 49 at the inner end of the flow passage 23 when the pressure acting inwardly on the ball is greater than the pressure acting outwardly thereon. The ball may be retained in the flow passage 23 by suitable pin 50 extending across the outer end of the flow passage. As the frustoconical seat 49 and ball 48 may not have perfect sealed engagement, some fluid pressure may leak from the flow passage 23 into the flow passage portion 27. However, should the fluid pressure thus delivered to passage portion 27 exceed that of the pressure relief mechanism seating the fluid is immediately discharged through the relief valve 47, thereby preventing undesirable application of the high pressure to the container 11.

Thus, once the apparatus 10 is attached to can 11 and element 13 is caused to pierce the can portion 12, the pressure in can 11 is prevented from exceeding a preselected maximum by relief mechanism 47 while controlled flow of fluid from container 11 to fluid receiver 24 is permitted by the selective positioning of the valve member 26. Excessive fluid pressure from the receiver 24 is prevented from presenting a hazardous condition in container 11 by the check valve 48 and maintained communication of the relief mechanism 47 with the flow passage 19 at all times.

Referring now to the embodiment of FIGS. 5 and 6, a modified form of fluid transferring apparatus 110 is shown to comprise an apparatus generally similar to apparatus 10 but having a modified arrangement of the pressure relief mechanism 47 and control valve 25. Thus, in apparatus 110, the tubular housing 140 further defines at its inner end the movable valve member 126 which seats on the annular valve seat 128 in body 114 at the inner end of the flow passage portion 120. The flow passage portion is maintained in communication with the relief valve mechanism at all times through a passage 151 in the lower end of the housing 140 communicating with the relief valve chamber 129 within the housing 140. When the valve member 126 is spaced from seat 128, communication is provided between flow passage portion 120 and flow passage portion 127 to permit flow of fluid from container 111 outwardly therethrough to outlet passage portion 123. However, at all times, whether the valve is open or closed, fluid may flow upwardly through flow passage portion 151 to the relief valve mechanism 139 to permit control of the fluid pressure in the container 111 by the pressure regulator 147. High pressure fluid discharging upwardly from the upper end 143 of housing 140 is directed back downwardly by downturned ports 152 in the handle 134 secured to the upper end of the tubular housing 140. Thus, the discharged pressurized fluid is directed back downwardly onto the body 114 and container 111 in the same manner as in apparatus 10. However, in apparatus 110, the handle 134 replaces the relief valve cover 44 of apparatus 10 to define the means for redirecting the discharged high pressure fluid to effect the desired cooling of the container 111 and, thus, lowering of the pressure therein. In all other respects, fluid transferring apparatus 110 is similar to apparatus 10 and elements of apparatus 110 corresponding to elements of apparatus 10 are identified by similar reference numerals, except 100 higher.

As discussed briefly above, the fluid transferring apparatus is illustrated in the form of a can tapper where the container 11 comprises a can of refrigerant fluid under pressure. Illustratively, conventional cans of Freon 12 refrigerant fluid are designed to hold the fluid at a pressure of 180 p.s.i. at a maximum temperature of 130.degree. F. If an abnormal higher temperature condition occurs, such as by leaving the can in a heated compartment such as the trunk of a car under hot summer conditions, the temperature can very easily rise to 160.degree. F. whereat the pressure of the fluid would be 280 p.s.i. and would present a serious hazard as a potentially explosive element. Freon 22 is normally maintained at a pressure of below 310 p.s.i. at a maximum temperature of 125.degree. F. and such a can would develop approximately 450 p.s.i. at the elevated 160.degree. F. temperature. Thus, it can be seen that abnormal high temperatures may readily be present in the cans of refrigerant fluid making it highly desirable to utilize the pressure reducing and relieving means of the present invention to alleviate such conditions. As indicated above, at times plumbers may use their torches to cause faster flow of the refrigerant fluid from the can 11 such as where the flowing refrigerant causes condensation in the flow passages substantially throttling the flow. Obviously, such abnormal heating may cause a serious hazard to arise in the absence of the use of the pressure reducing and relieving means of the present invention. Thus, as soon as the apparatus 10 or apparatus 110 is attached with the cover pierced by the piercing element of the fluid tranferring apparatus, the protective functioning of the apparatus is brought into play thereby increasing the safety of the use of the pressurized fluid cans. It is preferable that no throttling of the flow be effected during the transfer and, thus, the check valves 48 and 148 are preferably not spring biased.

Further, as the flow passage portion communication with the piercing element is open to the pressure relief valve in both embodiments at all times, it is not necessary, as indicated above, that the check valves 48 and 148 be positive in their operation. As will be obvious to those skilled in the art, the check valves could be replaced by restrictors which would prevent a backflow from the receiver 24 sufficiently fast to cause a buildup in the pressure in container 11, or 111, before the pressure is relieved by the relief valve mechanism. However, as it is desirable to maintain the outflow from the can 11 as free as possible, it has been found that the use of the check valve permitting relatively unimpeded flow outwardly through flow passage portion 23, or 123, is preferred to the use of the flow restrictor.

The foregoing disclosure of specific embodiments is illustrative of the broad inventive concepts comprehended by the invention.

Claims

We claim:

1. Apparatus for transferring pressurized fluid from a fluid container to a fluid receiver wherein the fluid pressure is lower than that in said first container, comprising: means defining a flow passage; means for connecting a first portion of the flow passage to said container and a second portion of the flow passage to said fluid receiver for fluid flow therebetween; pressure relief means connecting with said flow passage at a third portion intermediate said first and second portions for limiting the fluid pressure therein to a preselected maximum pressure; means for limiting reverse flow of fluid from said fluid receiver through said flow passage to permit said pressure relief means to the pressure of reverse-flowing fluid in said flow passage to said preselected maximum pressure; and valve means for selectively closing said flow passage between said second and third portions, said third portion being in connection with said first portion at all times for permitting said pressure means to effectively limit the fluid pressure in said container to said preselected maximum.

2. The fluid transferring apparatus of claim 1 wherein said valve means for selectively closing said flow passage extends through said third portion of said flow passage.

3. The fluid transferring apparatus of claim 1 wherein said container comprises a can of pressurized fluid.

4. The fluid transferring apparatus of claim 1 wherein said container comprises a can of pressurized fluid and said means for connecting said first portion of the flow passage thereto comprises means for piercing a portion of said can.

5. The fluid transferring apparatus of claim 1 wherein said pressure relief valve includes a cover for precluding direct outflow of the high pressure fluid from the pressure relief means, including means for turning the flow.

6. The fluid transferring apparatus of claim 1 wherein said pressure relief means is carried by said valve means.

7. The fluid transferring apparatus of claim 1 wherein said pressure relief means is provided with means arranged to direct relieved fluid toward said first container to cool the same.

8. The fluid transferring apparatus of claim 1 wherein said means for limiting reverse flow comprises a check valve provided in said second portion of the flow passage for substantially preventing flow of fluid under pressure from said fluid receiver.

9. Apparatus for transferring pressurized fluid from a fluid container, comprising: means defining a flow passage; means for connecting the flow passage to said container for flow of said fluid therefrom; valve means for controlling the flow of said fluid through said passage; and means communicating with said flow passage for directing fluid from said passage against said container as an incident of the pressure of the fluid in said container rising above a preselected abnormally high level so as to tend to cool the container and thereby cause a lowering of the fluid pressure therein.

10. The fluid transferring apparatus of claim 9 wherein said means for directing fluid against said container further defines means for discharging fluid from said container to tend to cause a lowering of the fluid pressure therein.

11. The fluid transferring apparatus of claim 9 further including means for discharging fluid from said container as an incident of the pressure of the fluid in said container rising above a preselected abnormally high level so as to tend to cool and thereby cause a lowering of the fluid pressure therein.

12. The fluid transferring apparatus of claim 9 wherein said connecting means includes means for piercing the fluid container to provide the connection between said container and flow passage.

13. The fluid transferring apparatus of claim 1 wherein said means for limiting reverse flow comprises means resisting reverse flow from the fluid receiver while permitting substantially unimpeded flow to the fluid receiver through said flow passage second portion.