Non-return valve and connection device for a non-return valve

Description

[0001] The invention relates to a check valve, in particular for a refrigeration or heating circuit, and a connection device for such a check valve.

[0002] A check valve is known from JP 2001 280521 A. This check valve comprises a multi-part housing, which includes a valve housing and a base housing. A valve closing member is provided in the valve housing, which, in an initial position, rests in the valve seat and closes a valve opening. A guide section is provided on the valve closing member and extends through the base housing. The valve housing has openings at an upper end opposite the valve seat, into which locking lugs on the base housing engage after the base housing has been positioned relative to the valve housing with the valve closing member interposed. The locking lugs engage firmly and positively with the undercut on the valve housing.In this check valve, the flow direction of the medium is in an axial longitudinal axis of the valve housing and the base body, along which the opening and closing movement of the valve closing element also takes place.

[0003] DE 10 2005 048 965 A1 discloses a multi-part backflow preventer comprising a housing cage and an upper part securely clipped to it. A valve body and a return spring are guided in the housing cage. The backflow preventer can be inserted, with some play, into a housing receptacle of a gas or liquid line. For this purpose, the backflow preventer has locking cams on an outer side of the housing cage that engage in a circumferential groove in the housing receptacle of the gas or liquid line.

[0004] DE 20 2016 104 461 U1 discloses a check valve with a two-part housing. An upper and lower part of the housing are firmly connected by a clip connection. This check valve is attached to an adapter plate of a heat exchanger by clipping.

[0005] A shut-off valve system for a master cylinder is known from DE 10 2007 041 163 A1. This shut-off valve system comprises an insert with a cylindrical valve housing and a cover element for closing an open side of the valve housing. The insert is inserted into a valve chamber of the shut-off valve system. After inserting the insert into the valve chamber, the insert is screwed into place with a nut that engages a female thread on the valve chamber, thereby clamping and securing the insert in the valve chamber.

[0006] A pressure valve is known from WO 00 / 01937 A2. This pressure valve comprises a valve housing with a bore which has an enlarged bore section. A valve body is inserted into the enlarged bore section. Before being installed in a housing, the valve body is held in the valve housing by a snap-in connection. Provision is made for an annular collar to be provided on the valve body which engages in a receiving annular groove in the wall of the through-bore in the valve housing. After the pressure valve has been inserted into a corresponding housing, the valve body is moved into its axial end position by a further component acting on the head piece of the valve body and held there. To seal the pressure valve to the housing, the components of the pressure valve are axially clamped by the further component acting on them.

[0007] A piston pump is known from EP 1 056 948 B1. This piston pump comprises a suction valve and a pressure valve, which has a valve closing body that is biased toward a valve seat by a preloading element. The pressure valve, including the associated preloading element, is attached to a separately operable component.

[0008] The invention is based on the object of proposing a check valve, in particular for a refrigeration or heating circuit, in which an easier installation in a connection point of a connection device is provided in order to control a flow rate of a medium.

[0009] This object is achieved by a check valve according to the features of claim 1. An interface is formed between the valve housing and the base housing by means of connecting elements, so that the interface between the valve housing and the base housing includes play in the axial direction of the check valve, by means of which the distance between the valve housing and the base housing can be varied. The interface can preferably be designed with locking connecting elements. This arrangement has the advantage that during installation of the check valve into a connection point of a connection device, a reduction in the axial direction is achieved due to tolerance compensation.The check valve preferably features a sealing arrangement between the valve housing and the connection point, as well as a sealing arrangement between the base housing and the connection point. In the axial direction, tolerances may occur in relation to the length and / or spacing of the connection sections or plug-in sections, respectively, between the connection section and the plug-in section, which respectively accommodate the valve housing and the base housing. These tolerances can be compensated for by designing the check valve, in which the valve closure element and the base body are adjustable with axial play over their overall length, at least to a small extent, due to the axial play.

[0010] Preferably, the base housing and the valve housing are guided so as to be displaceable relative to one another along their longitudinal axes. This allows for a simple change in the overall length of the check valve within the scope of the axial play, thereby providing increased tolerance when installing the check valve in the connecting device.

[0011] Advantageously, the interface between the valve housing and the base housing is designed to be radially rotatable relative to each other. This has the advantage that a preferred orientation is not required when installing the check valve into the connection point. Rather, it can be inserted into the connection point of the connection device in any orientation.

[0012] A further advantageous embodiment of the check valve provides that the interface comprises connecting elements that form a detachable connection. This also allows a part of the check valve, such as the valve housing and / or the valve closing element, which are subject to wear, to be replaced.

[0013] The connecting elements of the check valve are advantageously formed from a circumferential groove and at least one, preferably several, locking hooks. It is preferably provided that the circumferential groove is provided in the base housing, and the at least one locking hook is formed on the valve housing. Interchangeability is also possible. To create the play, it is preferably provided that the locking hook, starting from the undercut to the front end of the locking hook, has a length that is smaller than the width of the circumferential groove. This makes it easy to determine and limit the axial play.

[0014] The connecting elements forming the interface preferably each have guide surfaces directed toward one another, with one guide surface on the base housing extending from the circumferential groove toward the valve housing, and the guide surface of the connecting element adjacent to the undercut extending within the groove. This allows the interface to be designed to withstand greater loads.

[0015] Furthermore, it is preferably provided that a circumferential guide flange is provided on the valve housing facing the base housing, which is preferably interrupted in the radial direction by the at least one connecting element, in particular by the at least one locking hook. As a result, the function of the locking hook is separated from the guide flange, wherein preferably both the connecting element and the guide flange can engage an inner peripheral wall of the base housing.

[0016] Preferably, the valve housing, with the guide flange opposite the valve seat, is guided axially displaceably and / or radially rotatably on the guide surface of the base housing. This enables secure positioning of the valve housing relative to the base housing. At the same time, it can also provide a secure seat for the valve closing element in the regulating chamber formed between the valve housing and the base housing.

[0017] The size of the play or the axial displaceability between the valve housing and the base body is preferably designed as follows. When the connecting elements are arranged in the interface with play relative to one another, a distance between a mounting surface or mounting section provided on the base housing and an end face of the valve housing opposite the base housing comprises an installation length A that is smaller than an installation dimension E in the connection point of the connection device. When the base housing is arranged in relation to the valve housing without play, i.e. when the valve housing is pulled apart from the base housing, the check valve has a size that is greater than the installation dimension E, starting from the mounting surface or mounting section of the base housing to the end face of the valve housing.

[0018] A further preferred embodiment of the check valve provides that the valve housing comprises the valve opening aligned along the longitudinal axis of the valve housing and, extending from this, comprises a radial wall section, at the end of which, opposite the valve opening, at least the valve element for the interface is provided. The valve housing is thus designed in a cage-like manner. Within the cage-like valve housing, the valve closing element is guided displaceably along the longitudinal axis of the valve housing.

[0019] Furthermore, it is preferably provided that openings are provided in the radial wall section of the valve housing, which openings are elongated and extend in the circumferential direction of the wall section, wherein webs are provided between the openings, which connect the valve seat to the at least one connecting element of the valve housing. This arrangement enables the check valve to deflect a flow of a medium by 90°, for example, by supplying the flow axially to the valve housing and discharging it radially through the opening in the valve housing.

[0020] Advantageously, a guide rod or guide section is provided on the valve closure member, which extends into the base housing and is guided longitudinally displaceably within the base housing. Advantageously, the reset element is provided between the base housing and the valve closure member. This allows the reset element to be easily positioned in a home or closed position.

[0021] Advantageously, the check valve can consist of only four components: the base housing, the valve housing, the valve closing element, and the return element. Preferably, two or three sealing elements, in particular sealing rings, are sufficient, one provided on the valve housing and one on the base housing to seal the respective connection points at the connection point, and optionally a sealing element on the valve closing element.

[0022] The valve closure member preferably has guide lamellas opposite the closing surface adjacent to the valve closure member, which extend parallel to the longitudinal axis of the valve closure member. These guide lamellas, in addition to the guide element, which is slidably accommodated in the base housing, enable guidance of the valve closure member. Particularly with an axial flow feed and a radial deflection, this can prevent an eccentric alignment of the valve closure member relative to the longitudinal axis or the opening of the valve housing.

[0023] Advantageously, the guide lamellas have a radially outward-facing end face whose axial length is greater than the width of the openings. As a result, the guide lamellas extend beyond the openings in the radial wall section in an initial position of the valve closure member. This ensures secure guidance of the valve closure member within the valve housing, independent of the opening movement. Furthermore, the height of the guide lamella on the valve closure member can limit the opening movement of the valve closure member within the valve housing by ensuring that the guide lamella rests against the base body.

[0024] A further preferred embodiment of the check valve provides that the valve seat of the valve housing has a support surface facing the valve opening, against which the valve closing member rests in a closed position, and a sealing surface against which a sealing element of the valve closing member rests, wherein the support surface and the sealing surface are formed separately from one another. Advantageously, the support surface and the sealing surface can be directly adjacent to one another. This arrangement has the advantage that the closing movement of the valve closing member and the closed position are limited by the support surface. The sealing element of the valve closing member can rest against the sealing surface with a sealing effect without the entire closing force of the valve closing member acting on the sealing element. In this way, leakage or premature wear of the sealing element can be counteracted by inserting the material of the sealing element.

[0025] Furthermore, it is preferably provided that the support surface of the valve seat is oriented at an angle of 10° to 90° to the longitudinal axis of the valve housing. The sealing surface is preferably formed at an angle of 90° to the longitudinal axis of the valve housing or less. The sealing surface is preferably oriented at an angle that is smaller or larger than the angle of the support surface in order to form the valve seat.

[0026] If the angle of the sealing surface is smaller than that of the support surface, a radial seal of the valve seat can be achieved. If the angle of the sealing surface is larger than the support surface, an axially acting seal can also be achieved.

[0027] Preferably, the contact pressure of the sealing element of the valve closure member can be adjusted by adjusting the axial distance between the sealing surface and the contact surface on the valve seat. This allows for a sealing position of the sealing element on the valve closure member and also prevents excessive contact force acting on the sealing element in the closed position of the valve closure member in the valve seat, thus preventing the sealing element from flowing or settling.

[0028] A sealing element can be clamped, inserted, or pressed onto the valve closing member. In the case of a radial seal, the seal can preferably be inserted or inserted into a circumferential groove, for example as a sealing ring. Alternatively, the sealing element can also be vulcanized onto the valve closing member. Likewise, the valve closing member can be designed as a two-component component, on which a sealing element made of an elastomer is produced integrally with the valve closing member made of a thermoplastic material. In such a two-component component, a seal acting in the axial direction can be formed, in particular. Furthermore, the sealing element can be adhesively bonded to the valve closing member and / or held by a positive fit.

[0029] The valve housing and the valve closure member are preferably made of plastic. The base housing can also be made of plastic or a metallic material, in particular light metal or the like. Aluminum or an aluminum alloy or the like can preferably be used.

[0030] The object underlying the invention is further achieved by a connection device for a check valve, according to one of the previously described embodiments, in which the connection point in the base body of the connection device comprises a supply opening and an outlet opening, wherein a first plug-in section is provided between the supply opening and the outlet opening, in which the valve housing of the check valve can be positioned, and a second plug-in section is provided between the supply opening and a connection opening of the connection point, in which the base housing of the check valve can be fixed, wherein the base body of the check valve is fixed in the second plug-in section in the axial direction to the connection point by means of a releasable fastening means, and the valve housing is positioned in the first plug-in section so as to be displaceable in the axial direction.The check valve, in which the valve housing and the base housing are arranged to be displaceable relative to one another with axial play, particularly at the interface between the base housing and the valve housing, enables simple and secure installation at such a connection point. Tolerances between the first and second plug-in sections in the connection point of the connection device and / or in the installation dimension of the check valve can be compensated, particularly in the axial direction.

[0031] In the connection device, it is preferably provided that the check valve is fixed in the second plug-in section by a releasable fastening element. The base housing rests with a stop surface on a shoulder of the second plug-in section, and the base housing is held fixed to this shoulder by the releasable fastening element, which engages a mounting section of the base housing opposite the stop surface. For simple assembly, the base housing can be arranged in the second plug-in section with little play. This enables simple fixing of the check valve in the connection point. In particular, the design of the releasable fastening element as a retaining ring can ensure rapid assembly and securing of the check valve in the connection point. This releasable fastening element can be designed, for example, as a retaining ring or spring ring.This allows for easy installation. Furthermore, a mounting flange with a thread, a twist / lock connection, a bayonet lock, or similar can be provided as a detachable fastening element.

[0032] Furthermore, it is preferably provided that a sealing element is provided between the base housing and the second plug-in section, as well as between the valve housing and the first plug-in section. This sealing element is preferably aligned radially on the base housing and the valve housing. This enables a secure seal between the regulating chamber and the outlet opening on the one hand, and the supply opening and the regulating chamber on the other hand, of the check valve. Furthermore, easy insertion into the connection point can be enabled.

[0033] The invention, as well as further advantageous embodiments and developments thereof, are described and explained in more detail below with reference to the examples shown in the drawings. The features shown in the description and the drawings can be used individually or in any combination according to the invention. They show: Figure 1 a perspective view of a check valve, Figure 2 an exploded view of the check valve, Figure 3 a perspective view of a valve closing member, Figure 4 a schematic sectional view of the check valve in a closed position, Figure 5 a schematic sectional view of the check valve in an open position, Figure 6 a schematic partial view of an alternative design of the valve closing element in the valve housing, Figure 7a schematic sectional view of the check valve in a connection point of a connection device in a closed position, and Figure 8 a schematic sectional view of the check valve in the connection point of the connection device in a working position.

[0034] In Figure 1 A check valve 11 is shown in a perspective view. This check valve 11 comprises a base housing 12 and a valve housing 14. The valve housing 14 is connected to the base housing 12 via an interface 16.

[0035] In Figure 2 is an exploded view of the check valve 11 according to Figure 1 This exploded view shows the individual components of the check valve 11 and its structure.

[0036] The valve housing 14 is advantageously formed in one piece. This valve housing 14 preferably has a cage-like structure. On an end face 21 of the valve housing 14, which is opposite the base housing 12, a valve opening 22 is provided, which is surrounded by a valve seat 23. A valve closing member 25 is provided in the valve housing 14, which opens and closes the valve opening 22. The valve closing member 25 has a closing surface 26. A sealing element 27 is provided adjacent to this closing surface 26. This sealing element 27 is preferably provided in a radially circumferential groove of the valve closing member 25.

[0037] The valve closure member 25 further comprises a guide section 29, which is guided in a guide bore 31 in the base housing 12. A return element 33 is provided between the valve closure member 25 and the base housing 12. This return element 33 is preferably guided through the guide section 29 and held between the valve closure member 25 and the base housing 12.

[0038] The base housing 12 comprises an externally circumferential groove 35, which is provided for receiving a sealing element 36. Adjacent to this groove 35 and facing the valve housing 14, a stop surface 37 is provided on the base housing 12. Opposite this stop surface, a mounting surface or mounting section 38 is arranged on the base housing 12. The base housing 12 is, for example, cylindrical. On an outer end face 39, for example, a surface can be provided which serves for the arrangement, reception or introduction of information, such as a code, an order number, test number or the like. The outer end face 39 can be aligned flush with the mounting surface 38 or can be provided on a cylindrical housing section 40, which preferably rises above the mounting surface 38.The cylindrical housing section 40 on the base housing 12 preferably has a diameter of 20% to 80% of the size of a diameter of an opening 77 in a connection point 76 of a connection device 71 (. Figure 7 ) on.

[0039] The interface 16 formed between the base housing 12 and the valve housing 14 comprises connecting elements 41, 42. One of the connecting elements 41 is formed by one, preferably several, locking hooks, which are provided on the valve housing 14. One of the connecting elements 42 of the interface 16 is formed by an internally circumferential groove 42 on the base housing 12, as shown in Figure 4 This allows the valve housing 14 to be inserted into the base housing 12, and the locking hooks 41 engage in the groove 42. Advantageously, the interface 16 can be designed as a detachable connection.

[0040] For the central positioning of the valve housing 14 relative to the base housing 12, a guide flange 44 is provided opposite an end face 21 of the valve housing 14. This guide flange 44 is formed in sections in the radial direction. The locking hooks 41 are advantageously provided between the radially extending guide surfaces of the guide flange 44.

[0041] Between the guide surfaces 44 and the end face 21 of the valve housing 14, openings 46 extending preferably in the radial direction are provided. Between the openings 46, webs 47 extend, which position the guide section 44 and the valve seat 23 at a distance.

[0042] This valve housing 14 allows a medium to flow in axially through the valve opening 22 and subsequently flow out laterally radially through the openings 46. The valve housing 14 with the previously described components is preferably formed as a single-piece injection-molded part. The base housing 12 is preferably also formed as a single-piece part. This can be made of plastic or a metal, in particular light metal.

[0043] In Figure 3The valve closing member 25 is shown in perspective. Guide lamellas 51 are provided on a side opposite the closing surface 26. For example, three guide lamellas 51 are provided on the valve closing member 25 - preferably evenly distributed over the circumference. The guide lamellas 51 have radially outwardly facing end faces 52. These end faces 52 rest against an inner side of the valve housing 14 and guide the valve closing member 25 during an opening and closing movement. The length of the end faces 52 comprises a height which extends at least as wide as the opening 46 in the axial direction. As a result, starting from a closed position 54 ( Figure 4 ) of the valve closing member 25 up to an opening movement, an axial guidance of the valve closing member 25 can take place without hooking in the openings 46.

[0044] In Figure 4is a schematic sectional view of the check valve 11 according to Figure 1 shown in an assembled arrangement. The valve closing member 25 is provided in a closed position 54. The Figure 5 shows a schematic sectional view of the check valve 11, in which the valve closing member 55 is shown in an open position 55. A regulating chamber 24 is formed between the base housing 12 and the valve housing 14. Within the regulating chamber 24, the valve closing member 25 can be controlled between a closed position 54 and an open position 55. The maximum open position 55 of the valve closing member 25 can be limited by the length of the guide blades 51 and / or the guide section 29.

[0045] The return element 33 is preferably received and guided by a bore section 32 that is larger than the guide bore 31 in the base housing 12. The depth of the bore section 32 can be configured to determine a preload of the return element 33.

[0046] The sectional view according to the Figures 4 and 5 shows the interface 16, which is preferably detachable.

[0047] The first and second connecting elements 41, 42 of the interface 16 are aligned with each other with axial play. For this purpose, the locking hook 41 has a distance between a front side 58 of the locking hook 41 and an undercut 59 of the locking hook 41 that is smaller than the width of the circumferential groove 42. As a result, the valve housing 14 is arranged with axial play relative to the base housing 12.

[0048] The valve housing 14 has a valve seat 23 comprising a support surface 61 and a sealing surface 62. The closing surface 26 of the valve closing member 25 rests against the support surface 61 in the closed position 54. Adjacent to the support surface 61, or following the support surface 61 in the flow direction, is the sealing surface 62, against which the sealing element 27 of the valve closing member 25 rests in the closed position 54. The support surface 61 and sealing surface 62 are formed separately from one another. They preferably adjoin one another. Due to the support surface 61, the valve closing member 25 assumes a defined closed position 54. Due to the axial alignment of the sealing surface 62 to the support surface 61, the sealing element 27 can bear against the sealing surface 62 with a predetermined contact pressure. This contact pressure is less than the contact force of the valve closing member 25 in the support surface 61.Overstressing or settling of the sealing element 27 is thereby avoided.

[0049] In the embodiment according to Figure 5 It is provided that the support surface 61 is aligned at an angle α to the longitudinal axis 64 of the valve housing 14 or base housing 12, which, for example, lies in a range of 10° to 90°. The sealing surface 62 is aligned at an angle β to the longitudinal axis 64 of the valve housing 14, which is smaller than the angle α. With such an arrangement, the sealing element 27 can have a sealing effect in the radial direction.

[0050] In Figure 6A schematic sectional view of an alternative embodiment of the valve closing member 25 relative to the valve seat 23 is shown. In this embodiment, the sealing surface 62 is formed at an angle β that is greater than the angle α of the support surface 61 relative to the longitudinal axis 64 of the valve housing 14. Preferably, the sealing surface 62 is oriented perpendicular to the longitudinal axis 64 of the valve housing 14. The sealing element 27 engages a circumferential shoulder on the valve closing member 25, thereby providing an axial seal.

[0051] In this embodiment of the valve closure member 25 and the valve seat 23, the sealing element 27 can be formed on the valve closure member 25 as a two-component injection-molded part. The sealing element 27 can also be glued or fixed thereto by means of a form fit.

[0052] In Figure 7the check valve 11 is arranged in a connection device 71. This connection device 71 can have at least one supply opening 72 and at least one discharge opening 74. Between the supply opening 72 and the discharge opening 74, a connection point 76 is provided, through which a medium is passed. The check valve 11 can be inserted into the connection point 76 via an opening 77 and can be fixed to the connection point 76. The connection point 76 preferably has a first plug-in section 78, in which the valve housing 14 is positioned. Furthermore, the connection point 76 comprises a second plug-in section 79, in which the base housing 12 is positioned. When the check valve 11 is inserted into the connection point 76, the stop surface 37 of the base housing 12 preferably rests against or on a shoulder 81 of the second plug-in section 79. Subsequently, a releasable fastening means 82 is introduced into the connection point 86.This releasable fastening means 82 engages the mounting surface 38 of the base housing 12 and fixes the check valve 11 in the connection point 76. The releasable fastening element 82 can, for example, be designed as a retaining ring which can be fastened in a circumferential groove 83.

[0053] The check valve 11 preferably includes an installation dimension E, which is determined by a distance from the mounting surface 38 of the base housing 12 to the end face 21 of the valve housing 14. Furthermore, an axial clearance B exists between the first and second connecting elements 41, 42 at the interface 16. The installation length A can be increased or lengthened by the length of the axial clearance B.

[0054] An installation dimension E is provided for the connection point 76, which includes the first and second plug-in sections 78, 79. The installation length A of the check valve 11 is smaller than the installation dimension E when the valve housing 14 is positioned with clearance B relative to the base housing 12. This simplifies the assembly of the check valve 11 at the connection point 76. As soon as pressure from the medium acts on the check valve 11, this valve housing 14 can be displaced axially relative to the base housing 12 due to the clearance B. It can be provided that the end face 21 of the valve housing 11 rests against the front end of the first plug-in section 78, but the first and second connecting elements 41, 42 are still positioned with slight clearance relative to one another or are positioned without clearance relative to one another. This makes it possible to compensate for tolerances of the first plug-in section 78 on the one hand and further tolerances in the positioning relative to the second plug-in section 79.

[0055] From the Figures 7 and 8 It can be seen that both the base housing 12 and the valve housing 14 are each arranged to seal off the first and second connection sections 78, 79 by a sealing element 36. This results in flow through the check valve 11 from the supply opening 72 in the regulating chamber 24 of the valve housing 14 after the valve closing member 25 has been moved from the closed position 54 to the open position 55. The medium then flows through the openings 46 in the valve housing 14 into an annular channel 84 in the connection point 76 and from there via the discharge opening 74.

Claims

1. Check valve, in particular for a refrigeration or heating circuit, which is insertable in a connection point (76) of a connection device (71) which has a feed opening (72) for the feed of a medium and an outlet opening (74) for the discharge of the medium, - with a multi-part housing (12, 14), which comprises a valve housing (14) and a base housing (12), which is connectable to one another via an interface (16) by means of connecting elements (41, 42), - with a regulating chamber (24) formed between the base housing (12) and the valve housing (14), in which a valve closing member (25) is provided, which in a closed position (54) bears against a valve seat (23) of the valve housing (14) and closes an opening (22) in the valve housing (14) and is transferrable into a working position (55) against an actuating force of a resetting element (33) and releases the valve opening (22), wherein the valve housing (14) and the valve closing member (25) arranged displaceably in the regulating chamber (24) lie in a common longitudinal axis (64), characterized in - that the interface (16) between the valve housing (14) and the base housing (12) comprises an axial play (B), by means of which the distance between the valve housing (14) and the base housing (12) is varyable, and - that a distance between a mounting section (38) provided on the base housing (12), by means of which the base housing (12) is fixable to the connection point (76) by a releasable fastening element (82), and an end face (21) on the valve housing (14) opposite the base housing (12) has an installation length (A) when the base housing (12) is arranged with respect to the valve housing (14) with play (B), which is smaller than an installation dimension (E) in the connection point (76) and, when the base housing (12) is arranged relative to the valve housing (14) without play (B), the base housing (12) and the valve housing (14) have a length which is equal to or greater than the installation dimension (E) of the connection point (76).

2. . Check valve according to claim 1, characterized in that the base housing (12) and the valve housing (14) are guided so as to be displaceable relative to one another along the longitudinal axis (64) by the axial play of the interface (16) and are preferably guided so as to be rotatable radially relative to one another.

3. . Check valve according to one of the preceding claims, characterized in that the interface (16) comprises connecting elements (41, 42) which form a detachable connection between the base housing (14) and the valve housing (12).

4. Check valve according to claim 3, characterized in that the first connecting element (42), which forms the interface (16), is designed as a circumferential groove, and the second connecting element (41) consists of at least one, preferably several, latching hooks, which engages in the first connecting element (42), and preferably wherein the latching hook formed as the second connecting element (41), starting from an undercut (59) on the latching hook up to the end face end (58) of the latching hook, comprises a length which is smaller than the width of the circumferential groove (42).

5. Check valve according to one of claims 3 or 4, characterized in that the connecting elements (41, 42) each have guide surfaces directed towards one another, wherein a guide surface on the base housing (12) extends from the groove (42) in the axial direction onto the valve housing (14) and the guide surface arranged on the undercut (59) of the latching hook (41) extends in the groove (42).

6. Check valve according to one of the preceding claims, characterized in that a circumferential guide flange (44) is provided on the valve housing (14) pointing towards the base housing (12), and preferably the valve housing (14) is guided with the guide flange on the guide surface (44) of the base housing (12) so as to be axially displaceable and / or radially rotatable, and preferably the guide flange (44) is interrupted by at least one connecting element (41) designed as a latching hook.

7. Check valve according to one of claims 1 to 6, characterized in that the valve housing (14) comprises the valve opening (22) aligned in the longitudinal axis (64) to the valve housing (14), and this valve opening (22) is adjoined by a radial wall section, at the end of which opposite the valve opening (22) the at least one connecting element (41) of the interface (16) is provided and preferably openings (46) are provided in the radial wall section of the valve housing (14), which are elongate and extend in the circumferential direction and preferably webs (47) extend between the openings (46), which webs connect the valve seat (23) of the valve housing (14) surrounding the valve opening (22) to the connecting elements (41, 42).

8. Check valve according to one of the preceding claims, characterized in that a guide section (29) is provided on a valve closing member (25), which extends into the base housing (12) and is guided longitudinally displaceably therein and preferably the resetting element (33) is provided between the valve closing member (25) and the base housing (12) under a prestressing force and / or in that the valve closing member (25) has at least one guide blade (51) opposite the closing surface (26), which extends parallel to the longitudinal axis (64) of the valve housing (14) and preferably the guide plate (51) has a radially outwardly facing end face (52), the axial length of which is greater than the width of the aperture (46) in the radial wall section.

9. Check valve according to one of the preceding claims, characterized in that the valve seat (23) of the valve housing (14) has a bearing surface (61) on which the valve closing member (25) rests in its closed position (54) and has a sealing surface (62), against which a sealing element (27) of the valve closing member (25) bears, the bearing surface (61) and sealing surface (62) being formed separately from one another and preferably adjoining one another and, in particular, the sealing element (27) being stretched on, clamped on, vulcanized onto and / or glued onto the valve closing member (25).

10. Check valve according to claim 9, characterized in that the bearing surface (61) is aligned at an angle α between 10° and 90° to the longitudinal axis (64) of the valve housing (14) and preferably the sealing surface (62) is aligned at an angle β of 90° or less to the longitudinal axis (64).

11. Check valve according to one of claims 9 or 10, characterized in that a contact pressure of the sealing element (27) of the valve closing member (25) in the closing position (54) is adjustable by an axial distance of the sealing surface (62) to the contact surface (61) on the valve seat (23).

12. Check valve according to one of the preceding claims, characterized in that the valve housing (14) and / or the valve closing member (25) is made of plastic and the base housing (12) is made of plastic or of a metallic material, in particular a light-metal material.

13. A system comprising a check valve (11) according to any one of the preceding claims and a connection device (71) for said check valve (11), wherein the connection device (71) comprises: - a connection point (76) into which the check valve (11) is insertable from the outside via a connection opening (77) of the connection point (76), - a base body (73), in which a feed channel with a feed opening (72) is provided, which opens into the connection point (76) in the base body (73), - an outlet opening (74), which connects the connection point (76) to an outlet channel, - a first plug-in section (78) in the connection point (76), which is provided between the feed opening (72) and the outlet opening (74), in which the valve housing (14) is positionable, and - a second plug-in section (79) in the connection point (76), which is provided between the feed opening (72) and the connection opening (74), in which the base housing (12) of the check valve (11) is fixed, wherein the base housing (12) is fixed with a releasable fastening element (82) in the second plug-in section (79) in the axial direction to the connection point (76) and the valve housing (14) is positioned in the first plug-in section (78) of the connection point (76) so as to be displaceable in the axial direction.

14. System according to claim 13, characterized in that the check valve (11) is fixed in the second plug-in section (79) by a releasable fastening element (82), in which the base housing (12) rests with the stop face (37) on a shoulder (81) of the second plug-in section (79) and the releasable fastening element (82) on an assembly section (38) of the base housing (12), - which is opposite the stop surface (37), and fixes the basic housing (12) in the second plug-in section (79) and / or in that a sealing element (36), preferably a sealing element (36) acting in the radial direction, is provided between the basic housing (12) and the second plug-in section (79) and between the valve housing (14) and the first plug-in section (78).