Quick connect coupling having inverted guide and sealing zones

A coupling device including a tubular body defining a channel having a reception segment for receiving a pipe end, the reception segment being provided with a locking member for locking the pipe end in the reception segment, a sealing member for fitting tightly against an outside surface of the pipe end, a guide for guiding the pipe end in the reception segment, and an abutment for stopping the pipe end being pushed into the reception segment, wherein the sealing member is placed in a groove formed between the abutment and the guide, and the locking member is placed between the guide and an inlet to the reception segment.

BACKGROUND OF THE INVENTION

The present invention relates to a coupling device, more particularly of the quick-connect type, arranged to enable one end of a duct to be connected to an element of a fluid transport circuit, which element may be an element that emits or receives fluid, and in particular a pipe, a manifold, a member for regulating flow rate or pressure, an actuator, a tank, a pump, or the like.

Such a coupling device is shown inFIG. 6and generally comprises a tubular body1defining a channel2including a segment3for receiving a pipe end100(FIG. 3). In succession in a direction for inserting the pipe end100in the reception segment3, the reception segment comprises: a locking member4for locking the pipe end100in the reception segment3; a sealing member5for fitting tightly around an outside surface of the pipe end; a guide surface6for guiding the pipe end in the reception segment; and an abutment7for stopping the pipe end being pushed into the reception segment. By way of example, the locking member5is a clamp, as shown inFIG. 6, comprising a sleeve having one end subdivided into arms that are elastically deformable between a state for releasing the pipe end and a state for locking the pipe end. The clamp is movable axially in the reception segment between a pushed-in, release position in which the arms are in their release state, and a pulled-back locking position in which a surface of the body holds the arms in their state for locking the pipe end. The locking member4may also be a washer having an inside circumference subdivided into a plurality of teeth, the washer being deformable between a pipe-end passing state and a pipe-end locking state.

It is known that reversing of the pipe end as a result of traction being applied to the pipe end100, or as a result of the circuit being pressurized, gives rise to a space (zone A inFIG. 6) between the terminal face of the pipe end100and the abutment7. This space is larger with locking members of the clamp type than with those of the toothed washer type.

It is also known that the fluid tends to stagnate in this space, which constitutes a fluid retention zone. Such a retention zone is more particularly harmful when the fluid being transported is a perishable liquid that might deteriorate in the retention zone and pollute the liquid flowing in the circuit. Other pollutants, such as dirt, may also stagnate in the retention zone.

In order to remedy that drawback, proposals have been made for coupling devices in which the coupling is no longer sealed by the outside surface of the pipe end but via the terminal face thereof. In those coupling devices, the resilience of the sealing member compensates for the reversal of the pipe end, thereby preventing a retention zone being formed. Those coupling devices present the drawback that the abutment of the pipe end is not firm, such that an operator is not certain to have compressed the sealing member sufficiently to guarantee that the coupling remains sealed after reversal of the tube, or indeed that the coupling remains connected.

In fluid installations in which the quality of the fluid is monitored, provision is also made to clean the circuit regularly by causing a cleaning liquid to flow therein.

It is also known from document U.S. Pat. No. 4,643,466 a coupling device without any guiding surface for the pipe. In said coupling device, a ring is mounted in the channel in order to center the pipe in the device. Such a centering is different from a guiding which maintains a segment of the pipe along an axial direction of the channel.

SUMMARY OF THE INVENTION

The invention provides ways for limiting the risks of a transported fluid being polluted by pollutants present in retention zones of a coupling device.

The invention results from an approach that is different from that which has previously been favored. In this approach, that has been verified experimentally, the retention zone A that is usually taken into consideration, and that results from the pipe end reversing, is of dimensions that are large enough to allow fluid to flow even if the fluid flow rate therein is less than the flow rate close to the central axis of the coupling. The fact that such flow is possible enables a cleaning liquid to reach this zone, should that be necessary. In contrast, experiments have shown that the space existing between the outside surface of the pipe end and the guide surface of the body (zone B inFIG. 6) constitutes a retention zone that extends between the retention zone that is usually taken into consideration and the sealing member and that, because of its small dimensions, does not allow fluid to flow and thus cannot be washed by the cleaning fluid.

In accordance with the invention, there is thus proposed a coupling device comprising a tubular body defining a channel having a reception segment for receiving a pipe end, the reception segment being provided with a locking member for locking the pipe end in the reception segment, a sealing member for fitting tightly against an outside surface of the pipe end, guide means for guiding the pipe end in the reception segment, and an abutment for stopping the pipe end being pushed into the reception segment, wherein the sealing member is placed in a groove formed between the abutment and the guide means, and the locking member is placed between the guide means and an inlet to the reception segment. Thus, the position of the gasket makes it possible to prevent fluid reaching the pipe end guide zone, and as a result it cannot constitute a retention zone.

In a particular embodiment, the guide means comprise a bushing fitted in the reception segment and, preferably, the bushing includes a polygonal inside surface defining a passage of section smaller than the outside section of the pipe end, such as a hexagonal polygonal surface. This makes it possible to limit the ability of the pipe end to deform, e.g. towards ovalizing its section, since that might lead to poor contact and thus to leakage between the sealing member and the outside surface of the pipe end.

The bushing may possess a first axial dimension and a second axial dimension respectively in the vicinity of an inside outline and of an outside outline of the bushing, the first axial dimension being longer than the second axial dimension. This makes it possible to improve guidance of the pipe end in the body of the coupling device and to limit any risk of leakage resulting from the pipe end deforming.

The bushing also may include a flank of frustoconical shape beside the locking member, and said locking member is a clamp deformable between a locking state and a release state for the pipe end, and is movable axially between a pushed-in position in which the frustoconically-shaped flank holds the clamp in its release state, and a pulled-back position in which the clamp is held in its locking state by a surface of the body. In addition to its guidance function, the bushing then performs an additional function of assisting insertion and extraction of the pipe end by facilitating deformation of the clamp towards, and indeed beyond, its release state.

Advantageously, the sealing member occupies substantially all of the groove and, for example, the sealing member is of a shape that is complementary to the shape of the groove. The reversal of the pipe end then gives rise to a negligible space being released that does not include a portion remote from the central axis of the coupling such that fluid flow is facilitated therein.

The groove may have diverging flanks. The pressure of the fluid in the circuit then contributes to reinforced sealing by pressing the sealing member against the elements that surround it.

The present invention, accordingly, comprises the construction, combination of elements, and/or arrangement of parts and steps which are exemplified in the detailed disclosure to follow.

The drawings will be described further in connection with the following Detailed Description of the Invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the figures, the invention relates to a coupling device comprising a body1having a first section that is arranged to receive a pipe end100and a second section that is arranged to be connected to a channel of a fluid transport circuit element, which element may be an element for emitting or receiving fluid and in particular a pipe, a manifold, a flow rate or pressure regulator member, an actuator, a tank, a pump, or the like. The second section is itself known and comprises, for example, a threaded portion for engaging in a tapped segment of the channel. The second section does not form part of the subject matter of the invention and is not described in greater detail herein.

With reference more particularly toFIG. 1, the body1defines a channel2that is terminated beside the first section of the body1by a segment3for receiving the pipe end100.

The segment3is provided with a locking member4for locking the pipe end100in the segment3, a sealing member5for fitting tightly against an outside surface of the pipe end100, means given overall reference6for guiding the pipe end100in the segment3, and an abutment7for stopping the pipe end being pushed into the segment3.

The guide means6in this example are formed by a collar11projecting into the segment3and having an inside surface, here a cylindrical surface, that serves to guide the pipe end100.

The locking member4is received between the collar11of the guide means6and the inlet orifice of the segment3and is itself known. The locking member4in this example comprises a clamp formed by a sleeve having an end portion that is subdivided by axial slots into a plurality of arms, and an opposite end portion that projects outside the body1. The arms have respective free ends, each provided with a tooth projecting towards the central axis of the sleeve, and the arms are deformable between a locking plate in which the teeth define a through diameter that is smaller than the outside diameter of the pipe end100, and a release state in which the teeth define a through diameter equal to the outside diameter of the pipe end100. The free ends of the arms are also provided with respective outwardly-directed bulges for co-operating with a frustoconical wall portion of the segment3(this wall portion is generally referred to as a clamping cone), and the locking member4is movable:(i) between a pushed-in release position (close to the collar11) in which the arms are free to deform between their two states; and(ii) a pulled-back locking position (close to the inlet orifice) in which said frustoconical wall portion holds the arms in their locking position.

The sealing member5is located in a groove8formed between the abutment7and the collar11of the guide means6. In this example the sealing member5is made of an elasticall: compressible material in the form of an O-ring having an inside diameter that is smaller than the outside diameter of the pipe end. The groove8flares away from its maxim: circumference and possesses a frustoconical flank9connecting with the remainder of the channel2.

In the vicinity of its connection with the channel2, the frustoconical flank9possesses an annular portion of inside diameter smaller than the outside diameter of the pipe end100, thereby forming the abutment7.

It can be understood that when the pipe end100is inserted in the segment3, the pipe end100pushes the locking member4towards its release position and then passes through it. The pipe end100then passes into the collar11of the guide means6and into the sealing member5prior to touching the abutment7.

When the circuit is pressurized, the pipe end100reverses, thereby entraining the sealing member against the collar11of the guide means6and the locking member4towards its locking position in such a manner that the arms of the locking member4are deformed into their locking state where they clamp onto the pipe end100.

An operator can disconnect the pipe end100by pushing the locking member4into its release position while pulling on the pipe end100.

Elements identical or analogous to those described above are given the same numerical references in the embodiments described below with reference toFIGS. 2 and 5.

In the second embodiment shown inFIGS. 2 to 4, the guide means6are formed by a bushing21fitted in the segment3. By way of example, the bushing21is pushed into the segment3by force. The bushing21may also be crimped, adhesively bonded, blocked in position, or fastened by any other means suitable for preventing the bushing21from moving inside the segment3. The bushing21has a polygonal inside surface defining a passage of section that is smaller than an outside section of the pipe end100. The inside surface of the bushing21in this example has six flats within which there is inscribed a circle of diameter that is slightly smaller than the diameter of the pipe end100.

The abutment7is here formed by a radial surface portion of annular shape that extends from the flank9of the groove8.

The sealing member5is of a shape that is complementary to that of the groove8so as to fill it completely. Here the sealing member S has a cylindrical inside surface provided with an annular internal projection for locally exerting greater pressure on the pipe end100, thereby locally reinforcing contact and thus sealing between the sealing member and the pipe end100without excessively increasing resistance to the pipe end being pushed into the sealing member.

As above, the pipe end100is coupled by being pushed into the segment3until it comes into contact with the abutment7(FIG. 3).

Pressurizing the circuit causes the pipe end100to reverse together with the locking member4until the locking member reaches its locking position. Reversing through a distance L leaves a space of the same length L between the abutment7and the terminal face of the pipe end100(FIG. 4). This space is shallow (because of the presence of the sealing member5) and is easily washed during a cleaning operation that consists in causing a cleaning liquid to flow in the transport circuit.

In the third embodiment shown inFIG. 5, only the shape of the bushing of the guide means6is changed. The bushing31presents a first axial dimension and a second axial dimension respectively in the vicinity of an inner outline and of an outer outline of the bushing31, the first axial dimension being longer than the second axial dimension in order to improve the guidance of the pipe end100without increasing the size of the bushing31in the vicinity of the wall of the body1. The bushing31has two flanks32and33of frustoconical shape. The flank32is close to the free ends of the arms of the locking member4. The free ends of the arms of the locking member4have inside surfaces of a shape that is complementary to the shape of the flank32such that the flank32maintains the locking member in its release state when the locking member4is pushed into its release position. This makes it easier for the operator to disconnect the pipe end.

Naturally, the invention is not limited to the embodiments described, but covers any variant coming within the field of the invention as defined by the claims.

In particular, the locking member may be a clamp, a deformable toothed washer, a latch that is movable radially, or any other system for retaining the pipe end in the reception segment, such as a split ring, for example.

In a variant, the second section of the body1may be identical to the first section such that the coupling device enables two pipe ends to be united with each other.

The invention is usable in any type of fluid transport circuit, and in particular for transporting food fluids or paints.

In a variant, the groove8possesses diverging flanks.

As it is anticipated that certain changes may be made in the present invention without departing from the precepts herein involved, it is intended that all matter contained in the foregoing description shall be interpreted in as illustrative rather than in a limiting sense. All references including any priority documents cited herein are expressly incorporated by reference.