CN210398053U

CN210398053U - Stainless steel corrugated pipe with plug-in connector for connecting gas appliance

Info

Publication number: CN210398053U
Application number: CN201920425455.6U
Authority: CN
Inventors: 胡熙存; 张申正
Original assignee: Zhejiang Sanzee Pipes Industry Co ltd
Current assignee: Zhejiang Sanzee Pipes Industry Co ltd
Priority date: 2019-03-29
Filing date: 2019-03-29
Publication date: 2020-04-24
Anticipated expiration: 2029-03-29

Abstract

The utility model relates to a gas utensil connecting pipe technical field specifically, relates to a gas utensil is connected and is used nonrust corrugated steel pipe with bayonet interface, adopts the throat flange of metal material to hold tightly corrugated steel pipe's coating layer, and the field installation need not to be equipped with welding tool, reduces the field installation cost, has removed the safe risk that needs the welding operation when the field installation: the shrunk necking flange has high rigidity and cannot be distorted and deformed when the holding force is large, and the defect of tightness check of the elastic material reinforced ring in the traditional structure is overcome; increase the reinforcing snap ring in fixation nut, can exert outside pressure with the reinforcing snap ring when bayonet sealing boot is further compressed, the reinforcing snap ring receives the inboard toper conflict face of fixation nut to block the back and forms the shrink and block the green joint, reaches the effect of strengthening the green joint power of holding tightly for the green connects difficult not hard up, connects more stably.

Description

Stainless steel corrugated pipe with plug-in connector for connecting gas appliance

Technical Field

The utility model relates to a gas utensil connecting pipe technical field specifically relates to a gas utensil connects and uses nonrust corrugated steel pipe with bayonet interface.

Background

The stainless steel corrugated pipe is widely used in connection of a gas appliance and a gas pipeline, and generally comprises a corrugated pipe inner pipe, a rubber sleeve and a joint body, wherein the rubber sleeve is wrapped outside the corrugated pipe inner pipe and used for protecting the corrugated pipe inner pipe, and the joint body is arranged at the end part of the corrugated pipe inner pipe.

In the survival and manufacture of the stainless steel corrugated pipe, the installation of the joint body is the most critical, and the installation form of the joint body directly influences the sealing performance of the stainless steel corrugated pipe in a use state. The joint body usually comprises a rotating nut, a fixing nut and a sealing ring, wherein the rotating nut is sleeved at the end part of the stainless steel corrugated pipe in an inseparable mode, the fixing nut is in threaded connection with the rotating nut, the sealing ring is clamped between the rotating nut and the fixing nut, and when the gas pipeline or the gas appliance is connected, the sealing ring is pressed tightly through the rotating nut, so that the purpose of tightly holding the joint of the gas pipeline or the joint of the gas appliance is achieved. The inseparable connection between the swivel nut and the stainless steel corrugated pipe and the leakage problem from the tail hole of the swivel nut are particularly important.

The 'stainless steel corrugated hose joint assembly for gas delivery with leakage detection function' disclosed in the Chinese patent number 201020113219.X provides a technical scheme of a wave beating and strengthening ring, and discloses the following technical contents. When the gas transmission stainless steel corrugated hose is installed on site, a coating layer with a proper distance is peeled off from the end part of the gas transmission stainless steel corrugated hose, a joint nut is sleeved on the stainless steel corrugated hose, manual wave knocking (matched wave knocking tool) is carried out on the tail end of the stainless steel corrugated hose, a reinforcing ring is embedded into a wave trough of the stainless steel corrugated hose and is tightly attached to the stainless steel corrugated hose, the reinforcing ring is embedded into a joint groove, a joint component is provided with a sealing ring and a leakage detection hole, the leakage detection function of the joint is increased, and whether the gas transmission stainless steel corrugated hose leaks or not can be found in time; meanwhile, the tail hole of the joint nut in the joint assembly is enlarged, the coating layer does not need to be peeled off when the pipe sleeve joint nut is coated, the corrugated pipe is prevented from being exposed and leaked, the corrugated pipe is protected, and the product is more attractive. From the above technical solutions, no matter from which direction the reinforcement ring is assembled, the minimum diameter of the reinforcement ring is necessarily smaller than the flange rib formed after the cladding is called the outer diameter or the knocking, and the reinforcement ring is embedded into the wave trough. Therefore, it is reasonable to believe that the reinforcing ring disclosed in the technical scheme is not an elastic member, so that when the holding force is increased, a gap is generated between the reinforcing ring and the flange rib or between the reinforcing ring and the joint groove after the reinforcing ring is subjected to force and torque, and then gas is leaked towards the tail hole of the rotary nut of the joint nut, so that the annular groove is machined and formed at the tail hole accessory of the joint nut in the comparison document, and the sealing ring 2 is added for cover protection. However, we have found that it is disadvantageous that the sealing ring 2 is an elastic member and the coating is also an elastic member, and although the bottom of the sealing ring in fig. 1 of the patent document is opposite to the wave trough of the corrugated stainless steel pipe, i.e. the sealing ring 2 and the wave trough of the corrugated stainless steel pipe clamp the coating, it is unlikely that the position in the drawing is reached completely when installing in the field. That is, the bottom of the sealing ring 2 may be the valley position facing the stainless steel corrugated pipe, in this case, if gas leakage occurs, a large gas pressure may press the coating layer located at the valley position directly under the sealing ring 2 toward the valley direction, and further, a gap is formed to form gas leakage.

The reinforcing ring made of elastic material has the condition of distortion and further leakage caused by holding force. As the technical improvement, a metal reinforcing ring is adopted, the metal reinforcing ring, usually stainless steel, is sleeved on the exposed stainless steel corrugated pipe part, then the residual corrugations are punched to be flatly propped against the metal reinforcing ring, and a flange rib formed after punching is welded with the reinforcing ring into a whole by a ring welding method. The disadvantages of this method are: the technical requirement of girth welding is high, and leakage can be formed when the girth welding does not meet the standard; and a welding tool needs to be carried during field installation, so that the potential safety hazard of field installation is increased, and the installation cost is increased.

In addition, the traditional interface structure mostly adopts a direct-insertion type structure, the Green joint is kept locked by the friction force between insertion type sealing sleeves after being inserted, once the stainless steel corrugated pipe is impacted by external force, tensile force along the axis of the interface is generated, and the looseness and even separation between the Green joint and the stainless steel corrugated pipe interface are easily caused, so that gas leakage is caused.

SUMMERY OF THE UTILITY MODEL

To the not enough of prior art, the utility model provides a gas apparatus connects uses stainless steel corrugated pipe with bayonet interface.

The utility model discloses a stainless steel corrugated pipe with a plug-in interface for connecting gas appliances, the stainless steel corrugated pipe, a coating layer coated outside the stainless steel corrugated pipe, a rotating nut, a fixed nut and a plug-in sealing sleeve, the rotating nut is sleeved on the end part of the stainless steel corrugated pipe, the fixed nut is in threaded connection with the rotating nut, the plug-in sealing sleeve is arranged in the fixed nut, one end of the plug-in sealing sleeve is propped against the inner end part of the fixed nut, the other end of the plug-in sealing sleeve is propped against the end part of the stainless steel corrugated pipe, the end part of the stainless steel corrugated pipe is provided with at least one complete wave trough exposed outside the coating layer, the exposed part of the stainless steel corrugated pipe is sleeved with a necking flange tightly sleeved with the coating layer, the necking flange is made of metal material, the outer side of one end of the necking flange far away from the coating layer is provided with an outwardly protruding flange edge, the inner, the end part of one side of the necking flange, which is provided with the flange edge, is provided with an annular groove, and the stainless steel corrugated pipe exposed outside the necking flange is pressed in the annular groove after being flattened.

Preferably, the exposed part of the stainless steel corrugated pipe comprises at least two complete wave crests, two ends of the exposed part respectively comprise half wave troughs, and the inner snap ring is embedded into one complete wave trough which is closest to the coating layer on the exposed part of the stainless steel corrugated pipe.

Preferably, the thickness of the stainless steel corrugated pipe exposed outside the necking flange after being flattened is larger than the depth of the annular groove.

Preferably, the inner diameter of the plug-in sealing sleeve is larger than that of the stainless steel corrugated pipe, and the outer diameter of the plug-in sealing sleeve is larger than that of the annular groove.

Preferably, a reinforcing clamping ring 7 for locking the Green joint under the action of axial extrusion force is arranged between the plug-in sealing sleeve and the fixing nut, and the reinforcing clamping ring is made of plastic.

Preferably, the outer wall that reinforcing snap ring and fixation nut offseted one end is the toper face, and the one end that reinforcing snap ring and bayonet seal cover offseted all has to distribute along its circumference has a plurality of incision, and all incisions all extend to the other end of reinforcing snap ring, and fixation nut medial extremity is equipped with the toper conflict face of contact with the toper face of reinforcing snap ring.

Preferably, the included angle between the conical abutting surface and the axis of the fixing nut is larger than the included angle between the conical surface and the axis of the reinforced clamping ring.

Preferably, the depth of the notch and the height of the conical surface are both greater than half of the height of the reinforced snap ring.

Preferably, the outer diameter of the reinforced clamping ring is smaller than that of the insertion type sealing sleeve, and the inner diameter of the reinforced clamping ring is larger than that of the insertion type sealing sleeve.

Has the advantages that: the utility model discloses a tight stainless steel corrugated pipe's coating layer is embraced to the throat flange of metal material, and the interior snap ring of the throat flange after the throat is embedded into the stainless steel corrugated pipe's that exposes trough, through in impressing the ring channel of throat flange front end behind the flattening with remaining exposed stainless steel corrugated pipe, realize the sealed between throat flange and the stainless steel corrugated pipe through the mode that compresses tightly bayonet seal cover after fixation nut and the rotatory locking of swivel nut. The defects of high technical difficulty and high air leakage risk of end girth welding reinforced rings in the traditional process are overcome; the field installation need not to be equipped with welding tool, reduces the field installation cost, has removed the safety risk that needs welding operation when the field installation: the shrunk necking flange has high rigidity and cannot be distorted and deformed when the holding force is large, and the defect of tightness check of the elastic material reinforced ring in the traditional structure is overcome; need not to add the sealing washer near the tail-hole of swivel nut, the use of accessory has been reduced, reduce comprehensive cost and improved production efficiency, increase the reinforcing snap ring in fixation nut, can exert outside pressure with the reinforcing snap ring when bayonet sealed cover is further compressed, the reinforcing snap ring receives behind the blockking of the inboard toper conflict face of fixation nut to form the shrink and block the Green and connect, reach the effect of strengthening the power of holding tightly to the Green joint, make the Green connect difficult not hard up, connect more stably.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

fig. 1 is a schematic sectional structure view of a middle necking flange of the present invention;

FIG. 2 is a schematic view of a process flow for installing a reducing flange;

FIG. 3 is a schematic cross-sectional view of a first embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view of a second embodiment of the present invention;

FIG. 5 is a cross-sectional view of a reinforced clamp ring according to a second embodiment of the present invention;

fig. 6 is a schematic perspective view of a reinforced snap ring according to a second embodiment of the present invention;

description of reference numerals: the corrugated stainless steel pipe comprises a corrugated stainless steel pipe 1, a coating layer 2, a rotating nut 3, a fixing nut 4, an inserting type sealing sleeve 5, a necking flange 6, an inner clamping ring 6a, an annular groove 6b, a reinforcing clamping ring 7, a conical surface 7a and a notch 7 b.

Detailed Description

In the following description, numerous implementation details are set forth in order to provide a more thorough understanding of the present invention. It should be understood, however, that these implementation details should not be used to limit the invention. That is, in some embodiments of the invention, details of these implementations are not necessary. In addition, some conventional structures and components are shown in simplified schematic form in the drawings.

In addition, the descriptions related to "first", "second", etc. in the present invention are only for description purposes, not specifically referring to the order or sequence, and are not intended to limit the present invention, but only to distinguish the components or operations described in the same technical terms, and are not to be construed as indicating or implying any relative importance or implicit indication of the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

Fig. 1 shows the utility model discloses well throat flange 6's cross-sectional view, this throat flange 6 adopt the metal material that extensibility can be good, can not produce the phenomenon of fracture when the compression, and rigidity after the compression can reach the assurance. As shown in fig. 1, the left end of the throat flange 6 is extended with a flange edge, an inner snap ring 6a is provided at a position corresponding to the flange edge inside the throat flange 6, and an annular groove 6b is provided at an end portion of the throat flange 6 on the side having the flange edge. The left side of the necking flange 6 is of a tubular structure, and the tubular structure is used for tightly holding the coating layer 2 on the outer side of the stainless steel corrugated pipe 1 at a compression port.

As shown in fig. 2, the installation of the necking flange 6 comprises the following four steps:

step 1, peeling off the coating layer 2 with proper length, wherein three complete wave troughs are exposed after peeling off.

Step 2, sleeving the necking flange 6, so that the inner snap ring 6a of the necking flange 6 is opposite to the nearest complete wave trough of the coating layer 2.

The size requirement of the necking flange 6 is as follows: the single edge between the inner diameter of the inner snap ring 6a and the outer diameter of the stainless steel corrugated pipe 1 is left 0.05^-A 0.1mm gap. So as to ensure that the necking flange 6 can be smoothly sleeved outside the coating layer 2 before compression and the inner snap ring 6a can not be blocked by the wave trough of the stainless steel corrugated pipe 1, and in addition, the inner snap ring 6a can be ensured to be embedded into the wave trough after the necking flange 6 is compressed.Because the necking flange 6 is made of metal, the size reduction amount after compression is smaller.

And 3, compressing the outline dimension of the necking flange 6 by adopting a necking die or a necking tool. After compression, the tubular part of the reducing flange 6 is held tightly with the coating 2, while the bottom of the inner ring is embedded in the wave trough of the corrugated stainless steel pipe 1. The necking flange 6 is made of metal with good extensibility, so that cracking cannot occur during compression, and the rigidity after compression can be guaranteed.

And 4, flattening the stainless steel corrugated pipe 1 remained outside the necking flange 6, and pressing the flattened part of the stainless steel corrugated pipe 1 into the annular groove 6b of the necking flange 6. The depth of the annular groove 6b is at least smaller than the thickness of the two complete wave peaks, so that the thickness of the two wave peaks after being leveled is higher than that of the annular groove 6b, and further, after the fixing nut 4 and the rotating nut 3 are locked, the inserted sealing sleeve 5 can compress the leveling part.

Referring to fig. 3, a stainless steel corrugated pipe for connecting a gas appliance with an insertion type interface, a stainless steel corrugated pipe 1, a coating layer 2 coated outside the stainless steel corrugated pipe 1, a rotating nut 3, a fixing nut 4 and an insertion type sealing sleeve 5, wherein the rotating nut 3 is sleeved at the end part of the stainless steel corrugated pipe, the fixing nut 4 is in threaded connection with the rotating nut 3, the insertion type sealing sleeve 5 is arranged in the fixing nut 4, one end of the insertion type sealing sleeve 5 is abutted against the inner side end part of the fixing nut 4, the other end of the insertion type sealing sleeve 5 is abutted against the end part of the stainless steel corrugated pipe 1, the end part of the stainless steel corrugated pipe 1 is at least provided with a complete wave trough exposed outside the coating layer 2, the exposed part of the stainless steel corrugated pipe 1 is sleeved with a necking flange 6 tightly sleeved with the coating layer 2, the necking flange 6 is made of metal, an outwardly protruding flange edge, the inner side of the necking flange 6 is provided with an inner clamping ring 6a embedded into a wave trough of the stainless steel corrugated pipe 1 at a position corresponding to the flange edge, the end part of one side of the necking flange 6 with the flange edge is provided with an annular groove 6b, and the stainless steel corrugated pipe 1 exposed outside the necking flange 6 is pressed in the annular groove 6b after being punched.

The exposed part of the stainless steel corrugated pipe 1 comprises at least two complete wave crests, two ends of the exposed part respectively comprise half wave troughs, and the inner snap ring 6a is embedded into one complete wave trough which is closest to the coating layer 2 on the exposed part of the stainless steel corrugated pipe 1.

The thickness of the stainless steel corrugated pipe 1 exposed outside the necking flange 6 after being flattened is larger than the depth of the annular groove 6 b.

The inner diameter of the plug-in sealing sleeve 5 is larger than that of the stainless steel corrugated pipe 1, and the outer diameter of the plug-in sealing sleeve 5 is larger than that of the annular groove 6 b.

Referring to fig. 4-6, a reinforced snap ring 7 for locking the joint under the action of axial extrusion force is arranged between the plug-in seal sleeve 5 and the fixing nut 4, and the reinforced snap ring (7) is made of plastic material.

The reinforced snap ring 7 is made of high-strength plastic, such as POM, PE, PA, etc.

The outer wall that reinforcing snap ring 7 and fixation nut 4 offseted one end is conical surface 7a, and the one end that reinforcing snap ring 7 and bayonet seal cover 5 offseted all has to distribute along its circumference has a plurality of incision 7b, and all incisions 7b all extend to the other end of reinforcing snap ring 7, and fixation nut 4 medial extremity is equipped with the toper conflict face of 7a contact of conical surface with reinforcing snap ring 7.

When the reinforced snap ring 7 is squeezed, one end of the reinforced snap ring 7 at the notch 7b shrinks and clamps the green joint due to the restriction of the tapered interference surface.

The included angle between the axis of the conical contact surface and the axis of the fixing nut is larger than the included angle between the axis of the conical surface and the axis of the reinforced snap ring. The design of different angles improves the surface contact of equal angles into line contact, can effectively reduce the friction force between the enhanced snap ring 7 and the fixed nut 4 when moving, is favorable for enhancing the outward fixation of the snap ring 7, and further forms the contraction trend of one end of the notch 7 b.

The depth of the notch 7b and the height of the conical surface 7a are both greater than half of the height of the reinforced snap ring 7. The effect of this design is that the cut 7b and the tapered surface 7a form a partial overlap within the range of the height of the reinforcing snap ring 7, and the contact position of the tapered interference surface and the tapered surface 7a can form a contraction of one end of the cut 7b as the position of the tapered surface 7a overlapping the cut 7b approaches.

The outer diameter of the reinforced clamping ring 7 is smaller than the outer diameter of the plug-in sealing sleeve 5, and the inner diameter of the reinforced clamping ring 7 is larger than the inner diameter of the plug-in sealing sleeve 5. Such a practice ensures that the plug-in seal 5 applies a uniform force to the reinforcement snap ring 7, and ensures that the reinforcement snap ring 7 and the fixing nut 4 are only in contact with each other between the tapered surface 7a and the tapered abutting surface, thereby further reducing the resistance of the reinforcement snap ring 7 to outward movement.

The utility model discloses a coating layer 2 is held tightly to throat flange 6 of metal material, and in the interior snap ring 6a of throat flange 6 after the throat imbeds the trough of the stainless steel corrugated pipe 1 that exposes, impresses the ring channel 6b of throat flange 6 front end in through 1 flattening back of the exposed stainless steel corrugated pipe that will remain, realizes the sealing between throat flange 6 and the stainless steel corrugated pipe 1 through the mode that compresses tightly bayonet seal cover 5 after fixation nut 4 and 3 rotatory locking of swivel nut. The defects of high technical difficulty and high air leakage risk of end girth welding reinforced rings in the traditional process are overcome; the field installation need not to be equipped with welding tool, reduces the field installation cost, has removed the safety risk that needs welding operation when the field installation: the shrunk necking flange 6 has high rigidity and cannot be distorted and deformed when the holding force is large, and the defect of tightness check of the elastic material reinforced ring in the traditional structure is overcome; need not to add the sealing washer near the tail-hole of swivel nut 3, the use of accessory has been reduced, reduce comprehensive cost and improved production efficiency, increase reinforcing snap ring 7 in fixation nut 4, can exert outside pressure with reinforcing snap ring 7 when bayonet seal cover 5 is further compressed, reinforcing snap ring 7 receives forming the shrink after blockking of 4 inboard toper conflict surfaces of fixation nut and blocks the Green and connect, reach the effect of strengthening the tight power of holding to the Green joint, make the Green connect difficult not hard up, connect more stably.

The above description is only an embodiment of the present invention, and is not intended to limit the present invention. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. The utility model provides a gas apparatus connects uses corrugated stainless steel pipe with bayonet interface, corrugated stainless steel pipe (1), the cladding is at outside coated layer (2) of corrugated stainless steel pipe (1), swivel nut (3), fixation nut (4) and bayonet seal cover (5), corrugated stainless steel pipe's tip is located to swivel nut (3) cover, fixation nut (4) and swivel nut (3) threaded connection, fixation nut (4) are arranged in bayonet seal cover (5), the one end and the fixation nut (4) medial extremity of bayonet seal cover (5) offset, the other end of bayonet seal cover (5) offsets with corrugated stainless steel pipe's (1) tip, its characterized in that: the end part of the stainless steel corrugated pipe (1) is provided with at least one complete wave trough which is exposed outside the coating layer (2), the exposed part of the stainless steel corrugated pipe (1) is sleeved with a necking flange (6) which is tightly sleeved with the coating layer (2), the necking flange (6) is made of metal, the outer side of one end, away from the coating layer (2), of the necking flange (6) is provided with a flange edge which protrudes outwards, the position, corresponding to the flange edge, of the inner side of the necking flange (6) is provided with an inner snap ring (6a) which is embedded into the wave trough of the stainless steel corrugated pipe (1), the end part of one side, provided with the flange edge, of the necking flange (6) is provided with an annular groove (6b), and the stainless steel corrugated pipe (1) exposed outside the necking flange (6) is pressed in the annular groove (6b) after.

2. The corrugated stainless steel pipe for connection of a gas appliance having a plug-in type interface according to claim 1, wherein: the exposed part of the stainless steel corrugated pipe (1) comprises at least two complete wave crests, two ends of the exposed part respectively comprise half wave troughs, and the inner snap ring (6a) is embedded into the complete wave trough which is closest to the coating layer (2) on the exposed part of the stainless steel corrugated pipe (1).

3. The corrugated stainless steel pipe for connection of a gas appliance having a plug-in type interface according to claim 2, wherein: the thickness of the stainless steel corrugated pipe (1) exposed outside the necking flange (6) after being punched is larger than the depth of the annular groove (6 b).

4. A corrugated stainless steel pipe for connection of gas appliances having a plug-in type interface according to claim 3, wherein: the inner diameter of the plug-in sealing sleeve (5) is larger than that of the stainless steel corrugated pipe (1), and the outer diameter of the plug-in sealing sleeve (5) is larger than that of the annular groove (6 b).

5. The corrugated stainless steel pipe for connection to a gas appliance having a plug-in type interface according to any one of claims 1 to 4, wherein: and a reinforcing snap ring (7) for locking the Green joint under the action of axial extrusion force is arranged between the plug-in seal sleeve (5) and the fixing nut (4), and the reinforcing snap ring (7) is made of plastic material.

6. The corrugated stainless steel pipe for connection of a gas appliance having a plug-in type interface according to claim 5, wherein: the outer wall that reinforcing snap ring (7) and fixation nut (4) offset one end is toper face (7a), and reinforcing snap ring (7) all have along its circumference one end that offsets with bayonet seal cover (5) and distribute and have a plurality of incision (7b), and all incisions (7b) all extend to the other end of reinforcing snap ring (7), and fixation nut (4) medial extremity is equipped with the toper conflict face with the toper face (7a) contact of reinforcing snap ring (7).

7. The corrugated stainless steel pipe for connection of a gas appliance having a plug-in type interface according to claim 6, wherein: the included angle between the conical abutting surface and the axis of the fixing nut (4) is larger than the included angle between the conical surface (7a) and the axis of the reinforced snap ring (7).

8. The corrugated stainless steel pipe for connection of a gas appliance having a plug-in type interface according to claim 7, wherein: the depth of the notch (7b) and the height of the conical surface (7a) are both larger than half of the height of the reinforced snap ring (7).

9. The corrugated stainless steel pipe for connection to a gas appliance having a plug-in type interface according to claim 8, wherein: the outer diameter of the reinforced clamping ring (7) is smaller than that of the plug-in sealing sleeve (5), and the inner diameter of the reinforced clamping ring (7) is larger than that of the plug-in sealing sleeve (5).