A Deep-Sea Balanced Pyrotechnic Cable Cutting Device

Abstract

This invention discloses a deep-sea balanced pyrotechnic cable cutting device, comprising: a housing assembly, a pyrotechnic component, a pusher, and a cutter head; the housing assembly has an "L"-shaped structure, including a vertical section and a horizontal section; the horizontal section is a tubular housing structure with one open end and one closed end, with the closed end being away from the end of the vertical section; the pusher is coaxially disposed within the horizontal section, forming an annular cavity with the horizontal section; a cavity is provided within the vertical section, with a through hole at the bottom of the cavity communicating with the annular cavity; the pyrotechnic component is disposed within the cavity and electrically connected to an ignition device; the cutter head is disposed within the horizontal section and connected to the large-diameter section of the pusher, with the axial bearing area of ​​the pusher equal to that of the cutter head. In this invention, the external bearing surface of the pusher and the bearing surface of the cutter head experience the same force, offsetting the influence of large external back pressure. When the pusher and cutter head move, they only overcome the shearing force and a small frictional force of the cable, thus achieving applicability in deep sea environments.

Description

Technical Field

[0001] This invention belongs to the field of underwater equipment technology, specifically relating to a deep-sea balanced pyrotechnic cable cutting device. Background Technology

[0002] With the rapid advancement of marine technology and the increasing demand for deep-sea exploration, new types of deep-sea UUVs, underwater gliders, profiling buoys, oil and gas exploration equipment, and other equipment and platforms have attracted much attention. When these devices and platforms are in operation, it is often necessary to periodically or timely release underwater equipment, such as moorings and beacons, to the surface to transmit collected marine information to shore stations, surface platforms, or as communication relay nodes. This release requires cutting cables or securing mooring lines.

[0003] Therefore, cable cutting devices are one of the key components of deep-sea equipment and platform operations. Existing marine equipment and platforms mainly employ two methods for cable cutting: (1) using a mechanical cutter to cut the cable based on the equipment's own buoyancy; and (2) using pyrotechnics as a power source and designing an adaptive structure to cut the cable. Method (1) is susceptible to environmental interference, causing jamming and blockages, resulting in low reliability, and requires a certain level of buoyancy from the released equipment. Method (2), on the other hand, is widely used due to its advantages of being less affected by the environment, rapid response, high reliability, and small size.

[0004] The pyrotechnic power source cutting mechanism utilizes the high-temperature, high-pressure gas generated by the internal pyrotechnic agent when powered by an external power source. This gas propels the cutting blade within the mechanism to cut cables. However, currently, such mechanisms are only suitable for shallow waters deeper than 300 meters. In deep-sea environments (>300 meters) with high back pressure, they cannot cut cables or their reliability is significantly reduced due to the need to overcome the immense external pressure. Therefore, there is an urgent need for a cutting mechanism that is adaptable to deep-sea environments, highly reliable, responsive, and compact. Summary of the Invention

[0005] In view of this, the present invention provides a deep-sea balanced pyrotechnic cable cutting device, which counteracts the influence of large external back pressure by promoting the same force on the external pressure-bearing surface and the cutting head pressure-bearing surface. During operation, it only overcomes the shearing force of the cable and a small frictional force, thereby achieving the purpose of being applicable in the deep sea.

[0006] This invention is achieved through the following technical solution:

[0007] A deep-sea balanced pyrotechnic cable cutting device includes: a housing assembly, a pyrotechnic component, a pusher, and a cutting head;

[0008] The housing assembly has an "L" shaped structure, including a vertical section and a horizontal section;

[0009] The horizontal section is a tubular shell structure with one end open and the other end closed, and the closed end is far away from the end where the vertical section is located.

[0010] The horizontal section, from the open end to the closed end, consists of small diameter hole section I, medium diameter hole section I, large diameter hole section I, small diameter hole section II, and medium diameter hole section II.

[0011] The product includes a coaxially connected large-diameter section and a small-diameter section; the product is coaxially set in a horizontal section, with the small-diameter section mating with the small-diameter hole section I and the large-diameter section mating with the large-diameter hole section I, forming an annular cavity between the small-diameter section and the medium-diameter hole section I, and the annular cavity is axially sealed;

[0012] A cavity is provided in the vertical section, and a through hole communicating with the annular cavity is provided at the bottom of the cavity. The pyrotechnic device is placed in the cavity and is electrically connected to the ignition device.

[0013] The cutter head is set in the horizontal section, with one end connected to the large diameter section of the tube and the other end passing through the small diameter section II and located in the medium diameter section II. The cutter head and the small diameter section II are sealed together.

[0014] The cable to be cut is positioned radially between the cutter head and the closed end of the horizontal section;

[0015] The axial bearing area of ​​the product is equal to that of the cutter head, and the middle diameter bore section II of the housing assembly is connected to the outside.

[0016] Furthermore, the cutter head includes a cylindrical section and a wedge-shaped section connected in sequence; the cylindrical section is coaxially connected to the major diameter section of the pusher, and the diameter of the cylindrical section is equal to the diameter of the minor diameter section of the pusher;

[0017] The wedge-shaped section is used to cut the rope. The side of the wedge-shaped section facing the rope is the cutting edge, and the straight line where the cutting edge is located is perpendicular to the axis of the rope. The distance between the two ends of the cutting edge is equal to the diameter of the hole in the middle diameter section II.

[0018] Furthermore, the pyrotechnic cable cutting device also includes a positioning pin;

[0019] When the cable is not being cut, one end of the positioning pin is set on the housing assembly, and the other end is set in the positioning hole to axially position the cutter head;

[0020] When cutting cables, high-temperature and high-pressure gas acts on the stepped surface I formed by the large-diameter and small-diameter sections of the cutting tool, causing the positioning pin to break and the cutting head to move towards the closed end of the housing assembly.

[0021] Furthermore, the pyrotechnic cable cutting device also includes guide screws; the wedge-shaped section is provided with positioning holes and guide grooves extending axially;

[0022] One end of the guide screw is mounted on the housing assembly, and the other end of the guide screw is located in the guide groove;

[0023] When cutting cables, high-temperature and high-pressure gas acts on the stepped surface I formed by the large-diameter and small-diameter sections of the cable. Under the action of the guide screw, the cutter head moves axially towards the closed end of the housing assembly, thereby cutting the cable to be cut.

[0024] Furthermore, a knife anvil is fixedly installed inside the closed end.

[0025] Furthermore, the housing assembly includes a housing body, a sealing cap, a blade sleeve, a retaining sleeve, a wire retaining sleeve, and a clamping screw plug;

[0026] The main body of the shell is L-shaped, consisting of a vertical part and a horizontal part;

[0027] A partition is provided between the vertical and horizontal parts, and a groove is provided on the partition. The pyrotechnic device is fixedly placed in the groove. The bottom of the groove is provided with the aforementioned through hole. A sealing cap is sealed to the top of the vertical part to seal the top of the vertical part, forming the vertical section of the shell. A watertight connector is provided at the sealing cap to realize the electrical connection between the pyrotechnic device and the external ignition device.

[0028] The horizontal section is open at both ends, and the aforementioned small-diameter hole section I, medium-diameter hole section I, and large-diameter hole section I are all located within the horizontal section;

[0029] Let the opening end on the horizontal part away from the vertical part be the opening end A. One end of the cutter head sleeve extends coaxially into the opening end A and is provided with a flange in the middle for fixed connection with the horizontal part of the housing assembly; the other end is connected to the clamping screw.

[0030] The cutter head sleeve includes a large-diameter bore section II and the aforementioned small-diameter bore section II; a stepped surface II is formed between the small-diameter bore section II and the large-diameter bore section II; the ferrule is coaxially located inside the large-diameter bore section II and abuts against the stepped surface II;

[0031] The cable clamp is located inside the cutter head sleeve and between the clamp and the compression plug, and is used to hold and fix the cable to be cut.

[0032] Furthermore, the small-diameter section being promoted is sealed to the small-diameter bore section of the housing assembly by providing one or more sealing rings;

[0033] The large-diameter section being marketed is sealed to the large-diameter section of the housing assembly via a sealing ring;

[0034] The cylindrical section of the cutter head and the small-diameter bore section II of the housing assembly are sealed by one or more sealing rings.

[0035] Beneficial effects:

[0036] (1) The deep-sea balanced pyrotechnic cable cutting device provided by the present invention has the following characteristics: since the opening of the shell assembly and the middle diameter hole section II of the shell assembly are connected to the outside, the external pressure acts on the axial bearing surface of the pusher and the axial bearing surface of the cutter head in the axial direction at the same time. The pressures counteract each other. During the process of the pusher and the cutter head moving towards the closed end, only the shearing force of the cable and a small friction force need to be overcome. Therefore, the cable cutting device is not limited by the sea depth and can be used in the deep sea.

[0037] (2) The positioning pin in this invention can prevent the cutter head from shifting axially when the cable cutting device does not need to cut the cable, thereby ensuring the reliability of cutting.

[0038] (3) The guide screw in this invention can prevent the cutter head from rotating along the axis, thereby ensuring the reliability of cutting.

[0039] (4) In this invention, a knife anvil is fixedly installed inside the closed end, which facilitates the smooth cutting of the cable and improves the cutting reliability.

[0040] (5) The space formed by the cutter head sleeve, the wire clamping sleeve and the clamping screw plug of the present invention can effectively control the range of the splash after the cutter head moves, and prevent damage to adjacent equipment.

[0041] In summary, this invention uses pyrotechnics as the cutting power source. The pyrotechnics have a small charge, which improves safety; the pyrotechnics are small in size, which saves installation space; the device can be used in the deep sea and has the advantages of high reliability, simple structure, and low cost. Attached Figure Description

[0042] Figure 1 This is a cross-sectional view of a deep-sea balanced pyrotechnic cable cutting device according to the present invention. Figure I ;

[0043] Figure 2 This is a cross-sectional view of a deep-sea balanced pyrotechnic cable cutting device according to the present invention. Figure II ;

[0044] Figure 3 This invention relates to the application of a deep-sea balanced pyrotechnic cable cutting device. Figure I (Before cutting the cable);

[0045] Figure 4 This invention relates to the application of a deep-sea balanced pyrotechnic cable cutting device. Figure II (After cutting the cable);

[0046] 1—Promotion, 2—Shell body, 3—Pyrotechnics, 4—Cutter head, 5—Cutter head sleeve, 6—Clip sleeve, 7—Cable to be cut, 8—Cable clamp sleeve, 9—Anvil, 10—Pressure plug, 11—Sealing cap, 12—Watertight connector, 13—Positioning pin, 14—Guide screw. Detailed Implementation

[0047] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0048] This embodiment provides a deep-sea balanced pyrotechnic cable cutting device; see attached document. Figure 1 and 2 It includes the housing assembly, pyrotechnic component 3, pusher 1, and cutter head 4;

[0049] The housing assembly has an "L" shaped structure, including a vertical section and a horizontal section;

[0050] The horizontal section is a tubular shell structure with one end open and the other end closed, and the closed end is far away from the end where the vertical section is located.

[0051] The horizontal section, from the open end to the closed end, consists of small diameter hole section I, medium diameter hole section I, large diameter hole section I, small diameter hole section II, and medium diameter hole section II.

[0052] Product 1 includes a large-diameter section and a small-diameter section coaxially connected; Product 1 is coaxially set in the horizontal section, the small-diameter section is fitted with the small-diameter hole section I, the large-diameter section is fitted with the large-diameter hole section I, and an annular cavity is formed between the small-diameter section and the medium-diameter hole section I, and the annular cavity is axially sealed;

[0053] A cavity is provided in the vertical section, and a through hole communicating with the annular cavity is provided at the bottom of the cavity. The pyrotechnic device 3 is placed in the cavity and is electrically connected to the ignition device.

[0054] The cutter head 4 is set in the horizontal section, with one end connected to the large diameter section of the pusher 1, and the other end passing through the small diameter section II and located in the medium diameter section II. The cutter head 4 and the small diameter section II are sealed together.

[0055] The cable 7 to be cut is arranged radially between the cutter head 4 and the closed end of the horizontal section;

[0056] The axial bearing area of ​​the pusher 1 is equal to that of the cutter head 4, and the middle diameter hole section II of the housing assembly is connected to the outside.

[0057] This embodiment provides a deep-sea balanced pyrotechnic cable cutting device. After the pyrotechnic component 3 is ignited, it generates high-temperature, high-pressure gas in the annular cavity, which acts on the stepped surface I formed by the large-diameter section and the small-diameter section of the pusher 1, pushing the cutter head 4 to move towards the closed end of the housing assembly. Since the opening of the housing assembly and the middle-diameter hole section II of the housing assembly are connected to the outside, the external pressure acts on the axial bearing surface of the pusher 1 and the axial bearing surface of the cutter head 4 simultaneously in the axial direction. The pressures counteract each other. During the process of the pusher 1 and the cutter head 4 moving towards the closed end, they only need to overcome the shearing force of the cable and a small frictional force. Therefore, this cable cutting device is not limited by sea depth and can be used in the deep sea.

[0058] In one embodiment, the cutter head 4 includes a cylindrical section and a wedge-shaped section connected in sequence; the cylindrical section is coaxially connected to the large-diameter section of the pusher 1, and the diameter of the cylindrical section is equal to the diameter of the small-diameter section of the pusher 1; the wedge-shaped section is used to cut the rope, and the side of the wedge-shaped section facing the rope is the cutting edge, and the straight line where the cutting edge is located is perpendicular to the axial direction of the rope; the distance between the two ends of the cutting edge is equal to the diameter of the hole in the middle diameter hole section II;

[0059] Furthermore, the pyrotechnic cable cutting device also includes a positioning pin 13 and a guide screw 14; the wedge-shaped section is provided with a positioning hole and a guide groove extending axially.

[0060] When the cable is not being cut, one end of the guide screw 14 is set on the housing assembly, and the other end of the guide screw 14 is located in the guide groove; one end of the positioning pin 13 is set on the housing assembly, and the other end is set in the positioning hole to axially position the cutter head 4.

[0061] When cutting the cable, high-temperature, high-pressure gas acts on the stepped surface I formed by the large-diameter and small-diameter sections of the pusher 1, causing the positioning pin 13 to break. Under the action of the guide screw 14, the cutter head 4 moves axially towards the closed end of the housing assembly, thus cutting the cable 7 to be cut. The guide screw 14 prevents the cutter head 4 from rotating along the axis, thereby ensuring the reliability of the cutting.

[0062] In one embodiment, an anvil 9 is fixedly installed inside the closed end to facilitate the smooth cutting of the cable and improve cutting reliability.

[0063] In one embodiment, the housing assembly includes a housing body 2, a sealing cap 11, a blade sleeve 5, a retaining sleeve 6, a wire retaining sleeve 8, and a compression plug 10.

[0064] The main body 2 of the shell is L-shaped, including a vertical part and a horizontal part;

[0065] A partition is provided between the vertical part and the horizontal part, and a groove is provided on the partition. The pyrotechnic device 3 is fixedly placed in the groove. The bottom of the groove is provided with the aforementioned through hole. The sealing cover 11 is sealed to the top of the vertical part to seal the top of the vertical part and form the vertical section of the shell. A watertight connector 12 is provided at the sealing cover 11 to realize the electrical connection between the pyrotechnic device 3 and the external ignition device.

[0066] The horizontal section is open at both ends, and the aforementioned small-diameter hole section I, medium-diameter hole section I, and large-diameter hole section I are all located within the horizontal section;

[0067] Let the opening end on the horizontal part away from the vertical part be the opening end A. One end of the cutter head sleeve 5 is coaxially inserted into the opening end A and a flange is provided in the middle for fixed connection with the horizontal part of the housing assembly. The other end is connected to the clamping screw plug 10. The aforementioned anvil 9 is coaxially arranged in the clamping screw plug 10.

[0068] The cutter head sleeve 5 includes a large-diameter hole section II and the aforementioned small-diameter hole section II; a stepped surface II is formed between the small-diameter hole section II and the large-diameter hole section II; the ferrule 6 is coaxially located within the large-diameter hole section II and abuts against the stepped surface II; the ferrule 6, together with the cutter head sleeve 5 and the shell body 2 of the coaxial nested part, forms the aforementioned medium-diameter hole section II;

[0069] The cable clamping sleeve 8 is set inside the cutter head sleeve 5; and is located between the clamping sleeve 6 and the clamping screw plug 10, for clamping and fixing the cable 7 to be cut;

[0070] In this embodiment, the space formed by the cutter head sleeve 5, the wire clamping sleeve 8, and the clamping screw plug 10 can effectively control the range of the splashed material after the cutter head 4 moves, preventing damage to adjacent equipment.

[0071] In one embodiment, the small-diameter section of the pusher 1 and the small-diameter bore section I of the housing assembly are sealed by one or more sealing rings. In a specific embodiment, two sealing rings are provided at intervals. The large-diameter section of the pusher 1 and the large-diameter section I of the housing assembly are sealed by sealing rings, thereby achieving the sealing of the annular cavity.

[0072] The cylindrical section of the cutter head 4 is sealed to the small-diameter bore section II of the housing assembly by setting one or more sealing rings. In a specific embodiment, two sealing rings are set at intervals.

[0073] The blade sheath 5 is sealed to the housing body 2 by two sealing rings.

[0074] In this embodiment, all interfaces in contact with water adopt a double O-ring sealing design, which greatly improves the underwater sealing effect and eliminates the risk of accidental water ingress causing the pyrotechnic device 3 to fail.

[0075] In one embodiment, the cutter head 4 is made of high-hardness high-speed steel; the locating pin 13 is made of brass.

[0076] Assembly method:

[0077] The first step is to assemble the push-out module. Install the two O-rings into the corresponding grooves of push-out 1, and then install push-out 1 into the shell body 2. The push-out module is now assembled and ready for use.

[0078] The second step is to assemble the cutter head module. Connect the cutter head 4 and the retaining sleeve 6, then install the locating pin 13 and guide screw 14 into the corresponding threaded holes and tighten them. The cutter head cutting module is now assembled and ready for use.

[0079] The third step is to assemble the cutting module. Install two O-rings inside the cutter head sleeve 5, and then install the cutter head module into the cutter head sleeve 5.

[0080] The fourth step is to install an O-ring on the inner circumferential surface of the shell body 2, and then install another O-ring on the end face of the shell body 2. The cutting module is then installed into the shell body 2 and secured with screws at the flange.

[0081] Step 5: Install the pyrotechnic module. Use an electric detonator to test whether the pyrotechnic item 3 is within the acceptable range. If it is acceptable, install the pyrotechnic item 3 into the groove inside the main body 2. The pyrotechnic module is now installed and ready for use.

[0082] Step 6: Install the watertight connector 12 into the sealing cover 11 and tighten it.

[0083] Step 7: Connect the pyrotechnic device 3. Connect the ignition wire of the pyrotechnic device 3 to the wire of the watertight connector 12, and then coil the ignition wire neatly.

[0084] Step 8: Secure the sealing cap 11 to the shell body 2 with screws.

[0085] Step 9: Install the cable to be cut 7. Insert the cable 7 into the reserved position, and install the cable clamp 8, the anvil 9, and the clamping plug 10 in sequence.

[0086] The assembly process is now complete.

[0087] Working principle:

[0088] One or more balanced cable cutting devices are installed on deep-sea equipment or platforms as needed. When the deep-sea equipment or platform reaches the predetermined depth, the cutting mechanism receives an ignition signal. The high-pressure gas generated by the pyrotechnic 3 acts on the step surface I formed by the large-diameter section and the small-diameter section of the pusher 1, pushing the pusher 1 and the cutter head 4. Under the action of balanced external back pressure, the pusher 1 and the cutter head 4 only need to overcome the friction, the shearing force of the positioning pin 13 and the cable shearing force to cut the cable and achieve the predetermined function.

[0089] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A deep-sea balanced pyrotechnic cable cutting device, characterized in that, include: Housing components, pyrotechnics, sales and cutting heads; The housing assembly has an "L" shaped structure, including a vertical section and a horizontal section; The horizontal section is a tubular shell structure with one end open and the other end closed, and the closed end is far away from the end where the vertical section is located. The horizontal section, from the open end to the closed end, consists of small diameter hole section I, medium diameter hole section I, large diameter hole section I, small diameter hole section II, and medium diameter hole section II. The product includes a coaxially connected large-diameter section and a small-diameter section; the product is coaxially set in a horizontal section, with the small-diameter section mating with the small-diameter hole section I and the large-diameter section mating with the large-diameter hole section I, forming an annular cavity between the small-diameter section and the medium-diameter hole section I, and the annular cavity is axially sealed; A cavity is provided in the vertical section, and a through hole communicating with the annular cavity is provided at the bottom of the cavity. The pyrotechnic device is placed in the cavity and is electrically connected to the ignition device. The cutter head is located within the horizontal section and comprises a cylindrical section and a cylindrical section connected in sequence. One end of the cylindrical section is coaxially connected to the large-diameter section of the pusher, and the diameter of the cylindrical section is equal to the diameter of the small-diameter section of the pusher. The other end of the cylindrical section passes through the small-diameter hole section II, and the cylindrical section and the small-diameter hole section II are sealed together. A wedge-shaped section is located within the intermediate-diameter hole section II and is used to cut the rope. The side of the wedge-shaped section facing the rope is the cutting edge, and the straight line containing the cutting edge is perpendicular to the axis of the rope. The distance between the two ends of the cutting edge is equal to the diameter of the hole in the intermediate-diameter hole section II. The cable to be cut is positioned radially between the cutter head and the closed end of the horizontal section; The axial bearing area of ​​the product is equal to that of the cutter head, and the middle diameter bore section II of the housing assembly is connected to the outside.

2. The deep-sea balanced pyrotechnic cable cutting device as described in claim 1, characterized in that, The pyrotechnic cable cutting device also includes locating pins; When the cable is not being cut, one end of the positioning pin is set on the housing assembly, and the other end is set in the positioning hole to axially position the cutter head; When cutting cables, high-temperature and high-pressure gas acts on the stepped surface I formed by the large-diameter and small-diameter sections of the cutting tool, causing the positioning pin to break and the cutting head to move towards the closed end of the housing assembly.

3. The deep-sea balanced pyrotechnic cable cutting device as described in claim 1, characterized in that, The pyrotechnic cable cutting device also includes guide screws; the wedge-shaped section is provided with positioning holes and guide grooves extending axially; One end of the guide screw is mounted on the housing assembly, and the other end of the guide screw is located in the guide groove; When cutting cables, high-temperature and high-pressure gas acts on the stepped surface I formed by the large-diameter and small-diameter sections of the cable. Under the action of the guide screw, the cutter head moves axially towards the closed end of the housing assembly, thereby cutting the cable to be cut.

4. A deep-sea balanced pyrotechnic cable cutting device as described in any one of claims 1-3, characterized in that, An anvil is fixedly installed inside the closed end.

5. A deep-sea balanced pyrotechnic cable cutting device as described in any one of claims 1-3, characterized in that, The housing assembly includes the housing body, sealing cap, cutter head sleeve, ferrule, wire clamping sleeve, and clamping screw plug; The main body of the shell is L-shaped, consisting of a vertical part and a horizontal part; A partition is provided between the vertical and horizontal parts, and a groove is provided on the partition. The pyrotechnic device is fixedly placed in the groove. The bottom of the groove is provided with the aforementioned through hole. A sealing cap is sealed to the top of the vertical part to seal the top of the vertical part, forming the vertical section of the shell. A watertight connector is provided at the sealing cap to realize the electrical connection between the pyrotechnic device and the external ignition device. The horizontal section is open at both ends, and the aforementioned small-diameter hole section I, medium-diameter hole section I, and large-diameter hole section I are all located within the horizontal section; Let the opening end on the horizontal part away from the vertical part be the opening end A. One end of the cutter head sleeve extends coaxially into the opening end A and is provided with a flange in the middle for fixed connection with the horizontal part of the housing assembly; the other end is connected to the clamping screw. The cutter head sleeve includes a large-diameter bore section II and the aforementioned small-diameter bore section II; a stepped surface II is formed between the small-diameter bore section II and the large-diameter bore section II; the ferrule is coaxially located inside the large-diameter bore section II and abuts against the stepped surface II; The cable clamp is located inside the cutter head sleeve and between the clamp and the compression plug, and is used to hold and fix the cable to be cut.

6. A deep-sea balanced pyrotechnic cable cutting device as described in any one of claims 1-3, characterized in that, The small-diameter section being promoted is sealed to the small-diameter bore section of the housing assembly by setting one or more sealing rings; The large-diameter section being marketed is sealed to the large-diameter section of the housing assembly via a sealing ring. The cylindrical section of the cutter head and the small-diameter bore section II of the housing assembly are sealed by one or more sealing rings.

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