Limiting pipe clamp with multi-stage limiting adjustment and mounting method

Abstract

The invention discloses a limiting pipe clamp with a multi-stage limiting adjustment function and an installation method. The limiting pipe clamp comprises a U-shaped limiting pipe clamp, a U-shaped bolt and a multi-stage limiting assembly. The U-shaped bolt is used for being arranged on a pipeline in a sleeving mode, and the U-shaped limiting pipe clamp and the U-shaped bolt are detachably connected together through a fastener. The multi-stage limiting assembly is arranged on the contact face of the U-shaped limiting pipe clamp and the pipeline. The installation method comprises the steps that the U-shaped bolt is used for being arranged on a pipeline in a sleeving mode, and the U-shaped limiting pipe clamp and the U-shaped bolt are detachably connected together through a fastener; meanwhile, the multi-stage limiting assembly is installed on the contact face of the U-shaped limiting pipe clamp and the pipeline. According to the limiting pipe clamp, excellent service performance is shown, the adjustable multi-stage limiting structure can flexibly adapt to different working conditions, more accurate displacement control is provided, accurate limiting and fixing can be conducted on different load conditions, and therefore the service life of the limiting pipe clamp is remarkably prolonged, and the operation safety of a pipeline system is remarkably improved.

Description

Technical Field

[0001] The invention relates to a pipeline limiting device, in particular to a limiting pipe clamp with multi-stage limiting adjustment and an installation method. Background Art

[0002] In the field of thermal power generation, a large number of equipment and pipelines are operated under extreme service conditions. The main steam and main water supply pipelines are used under long-term high temperature and high pressure, and while generating certain thermal displacement, due to defects inside the pipelines, pipeline aging, creep, or various accidental accident conditions such as operating reference vibration, etc., external forces, support and hanger with limited position pipe clamps are used to limit and fix the pipelines, and at the same time control the displacement of the pipelines, absorb vibration and impact, and protect expansion joints, etc., to ensure the stability and safety of the pipelines during operation.

[0003] Under the conditions of deep peak regulation and million-unit operation, the service conditions of the limit pipe clamps have become more complex and demanding. With the implementation of deep peak regulation, the unit load fluctuates frequently, and the pipeline system needs to withstand more drastic temperature and pressure changes, resulting in increased thermal expansion and contraction of the pipeline. At the same time, the large capacity characteristics of the million-unit unit bring higher operating pressure and temperature, faster fluid velocity in the pipeline, more severe fluid excitation, and significantly increased external vibration and impact frequency. Traditional limit pipe clamps are usually rigid constraints. If a large displacement is limited, it is easy to cause failure and fatigue of the pipeline due to stress concentration exceeding the allowable stress. In more extreme service environments, traditional limit pipe clamps are often difficult to adapt to complex operating conditions due to insufficient adjustment capabilities, rigid design limitations, and poor buffering performance, resulting in stress concentration, structural damage, and fatigue failure during service. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and materials, and to provide a limit pipe clamp with multi-stage limit adjustment and an installation method. The multi-stage limit adjustment limit pipe clamp exhibits excellent service performance, and its adjustable multi-stage limit structure can flexibly adapt to different working conditions, provide more precise displacement control, and can perform accurate limit fixation under different load conditions, thereby significantly improving the service life of the limit pipe clamp and the operating safety of the pipeline system.

[0005] In order to achieve the above object, the present invention adopts the following technical solution: A position limiting pipe clamp with multi-stage position limiting adjustment, comprising a U-shaped position limiting pipe clamp, a U-shaped bolt and a multi-stage position limiting assembly; The U-shaped bolt is used to be sleeved on the pipeline, and the U-shaped limiting pipe clamp and the U-shaped bolt are detachably connected together through a fastener; the multi-stage limiting component is arranged at the contact surface between the U-shaped limiting pipe clamp and the pipeline.

[0006] A further improvement of the present invention is that the fastener is a locking nut.

[0007] A further improvement of the present invention is that the multi-stage limiting assembly includes a multi-stage limiting slot provided on the U-shaped limiting pipe clamp, and a multi-stage limiting block connected to the multi-stage limiting slot via a multi-stage limiting locking pin.

[0008] A further improvement of the present invention is that multi-stage locking pin reserved holes are evenly distributed on the multi-stage limiting card slot and the multi-stage limiting card block.

[0009] A further improvement of the present invention is that the multi-stage limiting card slot is in a W-shaped structure and cooperates with the multi-stage limiting card block.

[0010] A further improvement of the present invention is that the multi-stage limiting card slot is in a U-shaped structure and cooperates with the multi-stage limiting card block.

[0011] A further improvement of the present invention is that the pipe clamp body of the U-shaped limiting pipe clamp is a U-shaped bending structure, the two arms are parallel, and the bottom is an arc-shaped or circular contour, which can closely fit the outer wall of the pipeline.

[0012] A further improvement of the present invention is that through holes or threaded holes are provided at the ends of the two arms of the U-shaped limiting pipe clamp for installing U-shaped bolts.

[0013] A further improvement of the present invention is that a rubber pad is provided at the location where the U-shaped limiting pipe clamp abuts against the outer wall of the pipe.

[0014] A method for installing a position limiting pipe clamp with multi-stage position limiting adjustment, comprising: The U-shaped bolt is used to be sleeved on the pipeline, and the U-shaped limiting pipe clamp and the U-shaped bolt are detachably connected together through fasteners; at the same time, the multi-stage limiting component is installed at the contact surface between the U-shaped limiting pipe clamp and the pipeline.

[0015] Compared with the prior art, the present invention has at least the following beneficial technical effects: The multi-stage limit pipe clamp of the present invention significantly improves the pipeline fixing ability and service life through innovative structural design, especially showing unique advantages under deep peak regulation and complex working conditions. The U-shaped limit pipe clamp generates a large friction force through the pre-tightening force of the locking nut and the U-shaped bolt to achieve preliminary fixation, and a rigid U-shaped gasket is set at the contact point between the U-shaped bolt and the pipeline to increase the friction coefficient and enhance the impact and vibration resistance. In response to the creep and stress relaxation problems under high temperature and alternating loads, the multi-stage limit system provides a more reliable limit support. Through the cooperation of the multi-stage limit slot and the multi-stage limit block, as well as the evenly distributed multi-stage locking pin reserved holes, the limit position can be flexibly adjusted to meet the frequent load change requirements in deep peak regulation. The cooperation of the W-shaped multi-stage limit slot and the U-shaped multi-stage limit block not only greatly improves the limit strength, but also ensures the installation convenience and structural stability. Under high temperature, high pressure and alternating load environments, the multi-stage limit system can effectively alleviate pipeline displacement and stress concentration problems caused by thermal expansion and contraction or vibration, providing important guarantees for the safe and stable operation of the pipeline system. It is particularly suitable for extreme working conditions such as deep peak regulation and million-unit units. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a front view of a position limiting pipe clamp with multi-stage position limiting adjustment according to the present invention; Figure 2 The figure is a left side view of a position limiting pipe clamp with multi-stage position limiting adjustment according to the present invention.

[0018] Description of reference numerals: 1. U-shaped limit pipe clamp; 2. Pipe; 3. Multi-stage limit locking pin; 4. Multi-stage limit slot; 5. Multi-stage limit block; 6. Locking nut; 7. U-shaped bolt. DETAILED DESCRIPTION

[0019] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0020] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0021] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0022] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0024] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0025] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0026] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0027] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0028] Example 1 like Figure 1 and Figure 2 As shown, the present invention provides a limiting pipe clamp with multi-stage limiting adjustment, comprising a U-shaped limiting pipe clamp 1, a U-shaped bolt 7 and a multi-stage limiting assembly; the U-shaped bolt 7 is used to be sleeved on the pipeline 2, and the U-shaped limiting pipe clamp 1 and the U-shaped bolt 7 are detachably connected together by fasteners; the multi-stage limiting assembly is arranged at the contact surface between the U-shaped limiting pipe clamp 1 and the pipeline 2.

[0029] Among them, the U-shaped limit pipe clamp 1 and the U-shaped bolt 7 are detachably connected by fasteners. This design makes the limit pipe clamp extremely flexible during installation, disassembly and maintenance. When the pipeline needs to be repaired, replaced or adjusted, the position of the limit pipe clamp can be easily completed by loosening the fasteners without destroying the entire structure, which greatly reduces the maintenance cost and difficulty. The multi-stage limit assembly is arranged at the contact surface between the U-shaped limit pipe clamp 1 and the pipeline 2. This design can provide a more accurate and reliable limit function. Multi-stage limit means that the pipeline can be adjusted to different degrees of limit according to actual needs to meet the requirements of different pipeline systems for limit accuracy during operation. The U-shaped bolt 7 is used to be sleeved on the pipeline 2. This structural form makes the limit pipe clamp applicable to pipelines of different diameters. By selecting the appropriate U-shaped bolt specifications, the limit fixation of pipelines of various sizes can be easily achieved, expanding the application range of the product. The overall structure consists of a U-shaped limit pipe clamp, a U-shaped bolt and a multi-stage limit assembly, which is relatively simple and does not have an overly complex mechanical structure. The simple structure not only reduces the manufacturing cost, but also reduces the possibility of failure and improves the reliability and service life of the product.

[0030] In this embodiment, the fastener is a locking nut 6 .

[0031] In this embodiment, the multi-stage limit assembly includes a multi-stage limit slot 4 provided on the U-shaped limit pipe clamp 1, and a multi-stage limit block 5 connected to the multi-stage limit slot 4 through a multi-stage limit locking pin 3. The multi-stage limit slot 4 and the multi-stage limit block 5 are evenly distributed with multi-stage locking pin reserved holes.

[0032] Among them, the multi-stage limit slot 4 provided on the U-shaped limit pipe clamp 1, and the multi-stage limit block 5 connected to the multi-stage limit slot 4 through the multi-stage limit locking pin 3, this structural combination provides multiple limit positions. The user can install the multi-stage limit block 5 in the multi-stage limit slot 4 at different positions according to the displacement requirements in the actual operation of the pipeline, so as to achieve precise adjustment of the pipeline limit degree and meet the diversified requirements for pipeline limit under different working conditions. The multi-stage limit slot 4 and the multi-stage limit block 5 are evenly distributed with multi-stage locking pin reserved holes, which makes the installation position of the multi-stage limit block 5 in the multi-stage limit slot 4 have more choices and higher adjustment accuracy. By inserting the multi-stage limit locking pin 3 in different reserved holes, more detailed limit adjustment can be achieved to meet some pipeline systems with extremely high requirements for limit accuracy. The structure of the multi-stage limit assembly is relatively simple. The multi-stage limit slot 4 is directly provided on the U-shaped limit pipe clamp 1, and the multi-stage limit block 5 is connected to the multi-stage limit slot 4 through the multi-stage limit locking pin 3. During the installation process, it is only necessary to align the multi-stage limit block 5 with the appropriate multi-stage limit slot 4, and then insert the multi-stage limit locking pin 3 to complete the installation. The operation is convenient and fast, and the installation time and labor cost can be saved. When a component in the multi-stage limit assembly is damaged or the limit position needs to be adjusted, due to its simple structure and detachable connection mode, the maintenance personnel can easily disassemble the multi-stage limit locking pin 3, and remove the multi-stage limit block 5 from the multi-stage limit slot 4 for replacement or adjustment. This replaceability makes the maintenance work more efficient, can quickly restore the normal operation of the pipeline system, and reduce downtime. The use of the multi-stage limit locking pin 3 enhances the connection reliability between the multi-stage limit block 5 and the multi-stage limit slot 4. After the locking pin is inserted into the reserved hole, it can effectively prevent the multi-stage limit block 5 from loosening or shifting in the multi-stage limit slot 4, ensuring the stability and accuracy of the limit position. The matching structure of the multi-stage limit slot 4 and the multi-stage limit block 5 and the uniformly distributed multi-stage locking pin reserved hole design enable the multi-stage limit assembly to maintain good structural stability when bearing the force generated by pipeline displacement. The force distribution between the components is more uniform, reducing the situation of excessive local stress, thereby improving the service life and reliability of the multi-stage limit assembly and ensuring the long-term stable operation of the pipeline system.

[0033] In this embodiment, the multi-stage limiting slot 4 is in a W-shaped structure and cooperates with the multi-stage limiting block 5 .

[0034] In this embodiment, the multi-stage limiting slot 4 is in a U-shaped structure and cooperates with the multi-stage limiting block 5 .

[0035] In this embodiment, the pipe clamp body of the U-shaped limit pipe clamp 1 is a U-shaped bending structure, the two arms are parallel, and the bottom is an arc or circular profile, which can closely fit the outer wall of the pipe 2 to achieve uniform coverage and force. Through holes or threaded holes are provided at the ends of the two arms of the U-shaped limit pipe clamp 1 for installing U-shaped bolts 7, and used in conjunction with the locking nuts 6 to form an embracing fixing structure.

[0036] Among them, the pipe clamp body of the U-shaped limit pipe clamp 1 is a U-shaped bending structure, the two arms are parallel, and the bottom is an arc or circular profile. This design enables it to fit tightly against the outer wall of the pipe 2. Tight fit can effectively reduce the gap between the pipe clamp and the pipe, avoid shaking of the pipe when vibrating or under stress due to excessive gap, and improve the fixing effect of the pipe clamp on the pipe. Uniformly covering the outer wall of the pipe can make the clamping force on the pipe more evenly distributed, avoiding damage to the pipe caused by local stress concentration. This is particularly important for pipes subjected to internal pressure, external load or thermal expansion, and can effectively extend the service life of the pipe. Through holes or threaded holes are provided at the ends of the two arms of the U-shaped limit pipe clamp 1 for installing U-bolts 7, and used in conjunction with the locking nut 6 to form an embracing fixing structure. This embracing fixing structure can tightly clamp the pipe from both sides, provide a large clamping force, and reliably fix the pipe in the pipe clamp. Through holes or threaded holes are provided at the ends of the two arms, which facilitates the installation of the U-bolts 7. The installer can select the appropriate bolt specifications according to the actual situation and tighten them with the locking nut 6, which is simple and quick to operate. The U-shaped bending structure and adjustable installation method of the U-shaped limit pipe clamp 1 enable it to adapt to pipes of different shapes (such as circular, elliptical and other approximately circular cross-sections) and sizes. By selecting the appropriate U-shaped bolt 7 and adjusting the tightness of the locking nut 6, it is possible to fix pipes of different diameters, which has strong versatility and adaptability. The design of the through hole or threaded hole enables the U-shaped limit pipe clamp 1 to be easily used in conjunction with other connecting parts (such as brackets, hangers, etc.) to form a complete pipeline support and fixing system.

[0037] In this embodiment, a rubber pad is provided at the location where the U-shaped limiting pipe clamp 1 is in contact with the outer wall of the pipe 2 .

[0038] Example 2 like Figure 1 and Figure 2 As shown, the present invention provides a limit pipe clamp with multi-stage limit adjustment, which is mainly composed of a U-shaped limit pipe clamp 1, a pipeline 2, a multi-stage limit locking pin 3, a multi-stage limit slot 4, a multi-stage limit block 5, a locking nut 6 and a U-shaped bolt 7.

[0039] The U-shaped limit pipe clamp 1 fixes the U-shaped bolt 7 by locking the locking nut 6. At this time, the pre-tightening force generated by the locking nut 6 and the U-shaped bolt 7 leads to a large friction between the U-shaped bolt 7 and the pipe 2, which can initially play a role in fixing and limiting. However, due to the high temperature and alternating load in the service environment, considering the influence of creep and stress relaxation, the friction force is significantly reduced. At the same time, a rigid U-shaped gasket is provided at the contact part between the U-shaped bolt 7 and the pipe, which can increase the surface friction coefficient and improve the ability to resist impact and vibration.

[0040] The multi-stage limit card slot 4 and the multi-stage limit card block 5 are connected through the multi-stage limit locking pin 3, and there are evenly distributed multi-stage locking pin reserved holes on the multi-stage limit card slot 4 and the multi-stage limit card block 5. At the same time, the multi-stage limit card slot 4 is a W-shaped structure, and the multi-stage limit card slot 4 is a U-shaped structure, which cooperates with the multi-stage limit card block 5 to increase the limit fixing strength while ensuring convenient and quick installation.

[0041] The mechanical relationship of the limit pipe clamp is:

[0042] in is the normal contact force between the pipe and the pipe clamp system, is the friction coefficient between the rod and the inner wall of the sleeve, and F is the friction force between the pipe and the pipe clamp system.

[0043] Considering that the maximum angle between the load reverse direction and the vertical line is 6°, the moment balance relationship of the pipe clamp is obtained from formula (2):

[0044] Where H is the distance between the top axis of the hanger and the pipe, P is the force exerted by the hanger rod on the top axis of the hanger, and P x is its horizontal component, R is the outer diameter of the pipe, and F b It is the force exerted by the multi-stage limit system on the pipe.

[0045] It can be seen that due to P x Very small, even if the friction force F is 0, it does not need to be too large. b Therefore, the thickness of the multi-stage limit system can be designed to be very thin, so the weld with the pipe part is also smaller, reducing the impact of welding on the pipeline.

[0046] Example 3 like Figure 1 and Figure 2 As shown, the present invention provides a method for installing a limit pipe clamp with multi-stage limit adjustment, comprising: using a U-shaped bolt 7 to be sleeved on a pipe 2, and the U-shaped limit pipe clamp 1 and the U-shaped bolt 7 are detachably connected together by a fastener; at the same time, the multi-stage limit assembly is installed at the contact surface between the U-shaped limit pipe clamp 1 and the pipe 2.

[0047] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0048] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A position limiting pipe clamp with multi-stage position limiting adjustment, characterized in that: It comprises a U-shaped limit pipe clamp (1), a U-shaped bolt (7) and a multi-stage limit assembly; The U-shaped bolt (7) is used to be sleeved on the pipe (2); the U-shaped limit pipe clamp (1) and the U-shaped bolt (7) are detachably connected together via a fastener; and the multi-stage limit assembly is arranged at the contact surface between the U-shaped limit pipe clamp (1) and the pipe (2).

2. A position limiting pipe clamp with multi-stage position limiting adjustment according to claim 1, characterized in that: The fastener is a lock nut (6).

3. The position limiting pipe clamp with multi-stage position limiting adjustment according to claim 1 is characterized in that: The multi-stage limiting assembly comprises a multi-stage limiting slot (4) provided on a U-shaped limiting pipe clamp (1), and a multi-stage limiting block (5) connected to the multi-stage limiting slot (4) via a multi-stage limiting locking pin (3).

4. The position limiting pipe clamp with multi-stage position limiting adjustment according to claim 3 is characterized in that: The multi-stage limiting card slot (4) and the multi-stage limiting card block (5) are evenly distributed with multi-stage locking pin reserved holes.

5. The position limiting pipe clamp with multi-stage position limiting adjustment according to claim 3 is characterized in that: The multi-stage limit card slot (4) has a W-shaped structure and cooperates with the multi-stage limit card block (5).

6. The position limiting pipe clamp with multi-stage position limiting adjustment according to claim 3, characterized in that: The multi-stage limiting card slot (4) has a U-shaped structure and cooperates with the multi-stage limiting card block (5).

7. The position limiting pipe clamp with multi-stage position limiting adjustment according to claim 3, characterized in that: The pipe clamp body of the U-shaped limiting pipe clamp (1) is in a U-shaped bending structure, the two arms are parallel, and the bottom is in an arc or circular profile, which can fit tightly against the outer wall of the pipe (2).

8. The position limiting pipe clamp with multi-stage position limiting adjustment according to claim 7, characterized in that: Through holes or threaded holes are provided at the ends of the two arms of the U-shaped limiting pipe clamp (1) for mounting U-shaped bolts (7).

9. The position limiting pipe clamp with multi-stage position limiting adjustment according to claim 3, characterized in that: A rubber pad is provided at the location where the U-shaped limiting pipe clamp (1) is in contact with the outer wall of the pipe (2).

10. A method for installing a position limiting pipe clamp with multi-stage position limiting adjustment according to any one of claims 1 to 9, characterized in that: include: The U-shaped bolt (7) is used to be sleeved on the pipe (2), and the U-shaped limit pipe clamp (1) and the U-shaped bolt (7) are detachably connected together via a fastener; at the same time, the multi-stage limit assembly is installed at the contact surface between the U-shaped limit pipe clamp (1) and the pipe (2).

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