GB2299385A - A Fluid Coupling - Google Patents

Abstract

A fluid coupling for coupling refrigeration apparatus to sources of cryogenic gas or liquid includes a coupler 10 and receptor portion 52 which can be locked together by a rotatable locking ring 40 having locking claws which engage keepers 50 provided on the receptor 52. The receptor 52 is provided with valves which can be actuated by handles 16. Locking ring 40 prevents movement of the valve handles 16 until the coupler 10 and receptor 52 are securely coupled together. The coupler 10 and receptor 52 can only be uncoupled when the valve handles 16 are in the position to close their respective valves. Electric heating elements can be provided in the coupler 10 to heat the mating surfaces of the coupler 10 and receptor 52.

Description

A FLUID COUPLING The present invention relates to a fluid coupling and relates particularly, but not exclusively, to a coupling suitable for coupling refrigeration apparatus to sources of cryogenic gas or liquid.

Presently, there exist a number of chilling units for use in association with frozen or chilled food stuffs. Some, for example, make use of what are known as 'eutectic tubes or plates' which, when pre-cooled, gradually adsorb the heat from their surroundings and act to maintain the food at the required temperature. The eutectic material is usually pre-chilled by exposing it to a flow of liquid cryogen such as, for example, liquid nitrogen or carbon dioxide.

-The liquid cryogen is generally supplied by a conventional arrangement of insulated pipes connected to the refrigeration apparatus by screw couplings.

Such couplings are difficult and slow to operate when frozen by the passage of cryogenic gas or liquid therethrough. Also, a comparatively large quantity of cryogen is lost during connection or removal of the hoses.

It is an object of the present invention to provide a fluid coupling which reduces and possibly eliminates the above mentioned problems.

Accordingly, the present invention provides a fluid coupling comprises two mating portions, each mating portion having a fluid port provided thereon for coupling to the fluid port on the other portion, characterised by a valve for inhibiting or allowing the flow of fluid between ports, locking means for locking said two mating portions together and a latch for preventing the valve being operated so as to allow fluid to flow between ports until the two mating portions are securely coupled together.

Preferably, the valve includes an operating handle and said latch comprises a portion of said locking means which prevents the handle being moved to open the valve until said two mating portions are securely locked together.

Advantageously, the coupling further includes ejector means for driving the mating portions apart upon unlocking of said portions.

Preferably, said ejector means comprises a rotatable member on a first mating portion having a cam surface thereon for engagement with a corresponding surface on a second mating portion in a manner which causes said second mating portion to be displaced axially from the first mating portion upon rotation of said ejector means.

Conveniently, said ejector means is coupled for rotation with the locking means.

Advantageously, the fluid coupling includes a heater for heating at least one of the engaging surfaces of said mating portions.

In a particularly convenient arrangement, the coupling further includes a clutch operable for connecting said handle to said valve only upon latching together of said mating portions.

The handle and valve may each include a flat sided shaft portion and said clutch may comprise a rotatable member having a slot therein in which said flat sided shaft portions are engaged for rotation upon latching together of said mating portions.

In a particularly useful arrangement, the clutch is mounted on a mating portion other than that upon which said valve is mounted.

Conveniently, said ports may comprise ports for the passage of liquid cryogen.

One or other of the mating portions may form part of a cryogenic refrigeration apparatus.

The ports may include vapour and liquid ports.

The present invention will now be more particularly described by way of example only with reference to the accompanying drawings, in which: Figure 1 is an isometric view of the present invention as seen from the receptacle side; Figure 2 is a view in the direction of arrow A in Figure 1; Figure 3 is a sectional view through the axis of the valve spindle shown in Figures 1 and 2; Figure 4 illustrates the coupler locked to the receptacle and illustrates the 'unlocked' position of the valve actuator; Figure 5 is a section through one of the ports taken in the direction of arrows B-B in Figure 1; Figures 6 and 7 are a view of a coupler incorporating two valves and illustrate the locked and unlocked positions of the coupler.

Figure 8 illustrates a further feature of the present invention.

Referring now to the drawings in general but particularly to Figure 1, a coupler 10 comprises an outer casing 12, typicaily of aluminium, with an insulated handle 14 and a valve handle 16. A bridge piece 18 is secured to the outer casing by screws 20 and provides a mounting within the outer casing for one or more valves 22 and for the pipe work (not shown) joining hose connections 24a, 24b with inlet/outlet ports 26, 28 and possibly further ports 30, 32.

Attached to the outer surface of the bridge piece 1 8 are insulated facings 34 and a copper cover 36 which houses a plurality of electric heating elements 38 (Figure 5) connected to a source of electrical current via lines 39. A locking plate 40 is mounted on a spindle 42 which passes through the casing 1 2 and is connected at its otherwise free end to an ejector piece 44 mounted for rotation with the spindle and positioned proud of cover 36. The locking plate 40 is further provided with an operating handle 46 and locking claws 48 for engagement in keepers 50 provided on a receptor portion 52 of a component to which the coupler 10 is to be connected (see Figure 4).The locking plate 40 is provided with a blocking portion 54 which, in operation, prevents the locking plate being coupled to the receptor portion 52 unless the valve handle 1 6 is in its closed position. A more accurate picture of the blocking portion 54 valve handle 1 6 interaction can be obtained by referring to Figures 6 and 7 which illustrate the uncoupled and coupled positions respectively.

The receptor portion 52, again an aluminium casing, incorporates a recess 56, shown in section in Figure 1, to accommodate the ejector piece 44. The recess is provided with sloping sides 56a matching similar sloping surfaces 44a on ejector piece 44. On rotation of the locking plate and ejector. The sloping surfaces 44a climb the matching sides of the recess and in so doing push the coupler 10 away from the receptor portion 52 thus helping to free it from any ice which may have formed during the passage of refrigerant.

Valve 22 may be provided with a further safety feature in the form of, for example, a clutching arrangement as shown in Figures 1 and 3. The clutching arrangement comprises a clutch plate 58 which is freely rotatable on forked tongue 60 which forms a protrusion from receptor portion 52. The clutch plate 58 is provided with a slot 62 sized so as to correspond with flat portions 64, 66 provided on upper and lower valve spindles 68, 70, best seen in Figure 3.

The upper valve spindle 68 is mounted in a bearing 69 and coupled for rotation with the valve handle 1 6 whilst the lower valve spindle 70 is coupled for rotating the actuating portion of valve 22. A keyway 72 is provided on the coupler 10 for receiving the forked tongue and clutching arrangement as and when the coupler 10 is coupled to receptor portion 52. Once coupled, slot 62 surrounds confronting ends of upper and lower spindles 68, 70 and acts to couple them together,~such that operation of the valve handle will cause operation of the valve.

The above described coupler 10 may be used for coupling any one of a number of components together but lends itself particularly well to use as a coupling device for coupling cryogenic liquid feed hoses to a receptor portion of a chilling unit 70. The chilling unit 70 may, for example, comprise a plurality of eutectic tubes (not shown) which are pre-chilled by passing liquid cryogen therethrough and which act to chill any atmosphere drawn over their surface.

In such an arrangement, liquid cryogen, such as for example nitrogen, is taken in through port 24a and directed to port 26 via pipes (not shown) before it is passed to a corresponding inlet port on the receptor portion 52. Liquid cryogen may then be passed through the eutectic tubes so as to cool them in a manner well known in the art and therefore not described herein. Waste cryogen gas is expelled from the receptor portion and passed to outlet 28 from which it may be taken directly to exit hose 24b or directed for circulation to the interior of a container (not shown) in which the chilling unit is positioned.

If this latter option is employed then inlet and outlet ports 30, 32 respectively are employed for directing the gas back to the chilling unit 70, from which it may be circulated around the container, and for receiving waste chilling gas for exhausting via exit hose 24b.

A second valve arrangement 78, the handle of which is shown in Figures 6 and 7 may be employed for facilitating operation of the container pre-chilling mode of operation. The valving arrangement may be provided with a safety device including a further blocking portion 80 on the locking plate which prevents coupling unless the valve handle 82 of the second valve arrangement is in its closed position. Additionally, or alternatively, the second valve arrangement may include a clutching arrangement the same as that described above for use with valve 22 and therefore not described again herein.

In operation, the coupler 10 is offered up to the receptor portion 52 with the valve or valve handle 16, 82 in their 'closed' positions thereby to allow the locking plate 40 to be rotated such that locking claws 48 engage in keepers 50 on the receptor and lock the coupler in position with all the inlets/outlets and the ejector piece 44 lining up with corresponding portions on the receptor portion 52. During locking, blocking portions 54 and 80 (when provided) effectively act to prevent the valve handles being inadvertently moved from their 'closed' positions. Once coupled, the blocking portions 54, 80 can no longer prevent the valve/valves 22, 78 being operated and hence a flow of liquid cryogen can be commenced as soon as desired. Liquid cryogen flows through inlet 26 and acts to chill the eutectic elements before being vented in the form of a gas via outlet 28.If desired, valve 78 may be operated and waste gas directed to cool the interior of any container in which the chilling unit is positioned. Eventually, waste gas is vented via outlet pipe 24b. Whilst liquid cryogen is being supplied through the coupler 10, it may be desirable to heat the mating faces by passing an electrical current through heater elements 38. Such heating will help prevent the build up of frost or ice on the surfaces thereby helping prevent them freezing together. In the open position, the valve handles 16, 82 effectively act to prevent the locking plate 40 rotating and thus prevent inadvertent de-coupling whilst liquid cryogen is still flowing. Once the chilling operation is completed, the coupler may be removed by returning the handle or handles 16, 82 to their 'closed' positions and rotating locking plate 40 so as to remove locking claws 48 from keepers 50.

From Figure 8, it will be appreciated that a further flow control valve 100 may be incorporated as an additional safety feature whenever containers are to be transported by vehicles incorporating standard operator actuated twist locks 102 for securing the container to the vehicle (shown in part at 104). The twist locks 102 are fairly conventional and act to secure the container to the vehicle 104 upon operation of lever 106 which turns locking member 108 such that it engages with a complimentary portion (not shown) on the container itself. The further flow control valve 100 may be directly coupled to the twist lock 102 such that, in operation, liquid cryogen is prevented from passing through the valve unless the container is securely locked onto the vehicle. Once the valve is opened, liquid cryogen is permitted to flow to the fluid coupling of Figures 1 to 7 via supply pipe 24. Such a feature may be used to connect a small reservoir of liquid nitrogen provided on the vehicle so as to facilitate partial replenishment of the chilling capability should it have been lost during an earlier handling or loading operation.

Claims (11)

1. A fluid coupling comprises two mating portions, each mating portion having a fluid port provided thereon for coupling to the fluid port on the other portion, characterised by a valve for inhibiting or allowing the flow of fluid between ports, locking means for locking said two mating portions together and a latch for preventing the valve being operated so as to allow fluid to flow between ports until the two mating portions are securely coupled together.

2. A fluid coupling as claimed in Claim 1 in which said valve includes an operating handle and said latch comprises a portion of said locking means which prevents the handle being moved to open the valve until said two mating portions are securely locked together.

3. A fluid coupling as claimed in Claim 1 or Claim 2 in which the coupling further includes ejector means for driving the mating portions apart upon unlocking of said portions.

4. A fluid coupling as claimed in Claim 3 in which said ejector means comprises a rotatable member on a first mating portion having a cam surface thereon for engagement with a corresponding surface on a second mating portion in a manner which causes said second mating portion to be displaced axially from the first mating portion upon rotation of said ejector means.

5. A fluid coupling as claimed in claim 3 or Claim 4 in which said ejector means is coupled for rotation with the locking means.

6. A fluid coupling as claimed in any one of claims 1 to 5 including a heater for heating at least one of the engaging surfaces of said mating portions.

7. A fluid coupling as claimed in any one of claims 1 to 6 including a clutch operable for connecting said handle to said valve only upon latching together of said mating portions.

8. A fluid coupling as claimed in Claim 7 in which said handle and valve each include a flat sided shaft portion and said clutch comprises a rotatable member having a slot therein in which said flat sided shaft portions are engaged for rotation upon latching together of said mating portions.

9. A fluid coupling as claimed in Claim 7 or 8 in which said clutch is mounted on a mating portion other than that upon which said valve is mounted.

10. A fluid coupling as claimed in any one of Claims 1 to 9 in which said ports comprise ports for the passage of liquid cryogen.

11. A fluid coupling as claimed in any one of Claims 1 to 10 in which one or other of said mating portions forms part of a cryogenic refrigeration apparatus.

1 2. A fluid coupling as claimed in any one of Claims 1 to 11 including vapour and fluid ports.

1 3. A fluid coupling substantially as herein described by reference to Figures 1 to 5 of the accompanying drawings.