In the field of pipeline engineering, the traditional methods for maintenance and water modification in water supply pipelines, such as cutting off damaged pipelines and replacing them with new ones, adding tee fittings, and repairing the sockets of pipelines, have been unable to meet the needs of modern urban development due to their long water outage time, high labor intensity, low work efficiency, and backward technological means. Therefore, it is an urgent and arduous task to improve the maintenance efficiency of water pipe burst in the water supply network, shorten the water outage time, reduce the labor intensity, and generate good social benefits.
The (Hafer Joint Repairer) is a kind of shell used to repair the damage and leakage of pipelines, which is made of nodular cast iron and is a split-type emergency repair tool. It is mainly divided into head saddle-type pipe clamps and pipe body saddle-type pipe clamps. The working principle is to form a new sealing layer by mechanical means. The metal enclosed cavity is used to wrap the opening or leakage point. Through two arc-shaped nodular cast iron pieces, rubber is placed around them, and the two semi-arc pipes are connected together by bolts. Under the sealing action of the rubber, the leakage of the medium in the pipeline is prevented.
The saddle-type pipe clamp has a simple structure, mainly consisting of bolts, sealing rubber rings, and two bodies of nodular cast iron castings. It is easy to install. Just clamp the nodular cast iron castings at the corresponding position or leakage point of the water drainage and tighten the nuts to complete the water leakage point or the corresponding position of the water drainage. The saddle-type pipe clamp is mainly divided into large, medium, and small sizes.
In order to solve the urgent problems of pipeline excavation leakage and emergency hole opening on the pipeline during the construction process, a kind of saddle-type pipe clamp, emergency repair device, and mechanical tee were developed and produced by using the Dongjiu line, static pressure line, and lost foam casting process. After the installation, pressure, rubber ring sealing, and other process tests, the product performance and structural design met the construction requirements and the requirements of customers.
- Structure and Working Principle of the Saddle-type Pipe Clamp
- The saddle-type pipe clamp is a kind of pipe fitting used for branch hole opening to connect the branch pipe and the main pipe section. It is the confluence hub of the urban pipe network connection, which is convenient for the diversion of the waterway. With the deepening of China’s urbanization, the development of modern municipal affairs pays more and more attention to meeting the requirements of environmental protection and durability. The characteristics of the saddle-type pipe clamp include high strength, good rigidity, good sealing performance, good corrosion resistance, simple assembly, convenient construction, and low maintenance cost. The schematic diagram and specifications of the saddle-type pipe clamp are shown in Figures 1 and 2.(a) Type A
(b) Type B
(c) Type C
Figure 1 Schematic diagram of pipe clamp (for the type below DN400)(a) Type A
(b) Type B
(c) Type C
Figure 2 Schematic diagram of pipe clamp (for the type above DN400)
- The saddle-type pipe clamp is a kind of pipe fitting used for branch hole opening to connect the branch pipe and the main pipe section. It is the confluence hub of the urban pipe network connection, which is convenient for the diversion of the waterway. With the deepening of China’s urbanization, the development of modern municipal affairs pays more and more attention to meeting the requirements of environmental protection and durability. The characteristics of the saddle-type pipe clamp include high strength, good rigidity, good sealing performance, good corrosion resistance, simple assembly, convenient construction, and low maintenance cost. The schematic diagram and specifications of the saddle-type pipe clamp are shown in Figures 1 and 2.(a) Type A
- Process Design and Analysis of the Saddle-type Pipe Clamp
- The material of the saddle-type pipe clamp is QT420 – 5. The saddle-type pipe clamp above DN300 is cast by the lost foam casting process, and the one below DN300 is cast by the sand casting process. Taking the DN700 and DN100 saddle-type pipe clamps as examples, after the model is made, the processes of dip coating, molding, pouring, grinding, processing, and hydraulic pressure testing are carried out by the lost foam casting process. According to the analysis of the product structure, considering the particularity of the lost foam casting process and the sand feeding problem in the molding process, the product placement method is set to have the opening facing upward to ensure the smooth sand feeding of the product.
- Iron Water Composition: After many tests, in order to ensure the spheroidization grade and hardness of the iron water, the content of each element was finally determined. The melting carburizer needs to use graphitized carburizer with fewer impurities.
- Pouring Process Design: The pouring temperature is controlled at 1510 – 1530 °C, and the specific range is adjusted according to the test results. Under the premise of ensuring that the pouring process does not cause the box to expand, the vacuum degree should be reduced as much as possible; if the vacuum degree is too large, the sand compactness will be large, and the surface of the casting is prone to sand sticking. A negative pressure in the range of 0.04 – 0.06 MPa is more appropriate; it is necessary to cover the film for pressure preservation, and the initial interval of the pressure preservation time is 10 – 15 min. Under the premise of ensuring that the box does not expand, the faster the better.
- Type Test: The type test scheme refers to the test scheme in the standard “GB/T 13295 – 2019”. According to the requirements of the standard, the type test scheme for the DN700 * DN100 saddle-type pipe clamp is formulated.
- Test Equipment and Materials: No. 9 hydraulic press and supporting platform, a set of pressure test tooling, a 0.5 mm rubber pad (100 mm), safety facilities such as protective nets, etc.
- Test Process: (1) Install the opener at the socket end of the DN700 disk insert and place it on the test platform. (2) Install the water pressure tooling and the DN700 disk insert, and try to keep the upper plane horizontal. Adjust the front and back until the whole is stable without shaking. (3) Connect the high and low-pressure water pipes to the pressure test tooling plane, then increase the pressure to the gauge pressure of 2.5 MPa, and after holding the pressure for 10 min, release the pressure. (4) Inspect whether the product leaks.
- Test Results: (1) There were no abnormal situations during the test. (2) Through the hydraulic pressure holding test, it can be verified that the DN700 * DN100 opener has no leakage during use. (3) The pipe fittings after the test have no damage, cracks, or deformation, and meet the use requirements.
- Application of the Saddle-type Pipe Clamp
- This product can realize narrow and pressure plugging, thereby solving the problem of rapid plugging of the pipeline due to various problems leading to leakage without shutting down the transportation. It can complete the rapid and safe emergency repair of the pressurized accident pipeline without interrupting the transportation of the pipeline medium, reduce the waste and potential safety hazards caused by the leakage of the medium, ensure the normal operation of the pipeline, and reduce the economic losses caused by the system shutdown and the discharge of the materials in the pipeline.
- At present, it has been trial-used in multiple engineering projects, and the use situation is good, and the installation is simple and convenient. See Figure 7 for the on-site construction photos of the saddle-type pipe clamp.Figure 7 Site construction photographs of saddle-type pipe clamp
- Conclusion
- The saddle-type pipe clamps produced by lost foam casting and sand casting have passed the engineering application, and the product performance and structural design meet the requirements of the construction party. It improves the work efficiency of urban water supply and drainage pipe network maintenance, reduces the labor intensity, reduces the damage to municipal facilities, and improves the economic and social benefits of the urban water supply and drainage industry.
In summary, the development and application of the nodular cast iron saddle-type pipe clamp by lost foam casting have significant advantages and application prospects. The following is a detailed discussion of the related content.
I. Introduction
The need for efficient and reliable pipeline systems is crucial in modern infrastructure. As municipal pipeline engineering undergoes more frequent reconstruction and expansion, there is an urgent demand for solutions to address issues such as water leakage during excavation and the need for hole opening in the pipeline construction process. Traditional maintenance methods in water supply pipelines have proven to be inefficient and unable to meet the requirements of modern urban development. Therefore, the development of innovative pipeline components, such as the saddle-type pipe clamp, becomes essential.
II. Design and Structure of the Saddle-type Pipe Clamp
The saddle-type pipe clamp is a key component in pipeline systems, designed to facilitate branch connections and provide reliable sealing. It consists of several main parts, including bolts, sealing rubber rings, and two bodies of nodular cast iron castings. The design of the saddle-type pipe clamp takes into account factors such as strength, rigidity, sealing performance, corrosion resistance, and ease of installation. Different types and sizes of saddle-type pipe clamps are available to meet the diverse needs of various pipeline applications.
| Type | Features | Application |
|---|---|---|
| Head Saddle-type Pipe Clamp | Designed for specific pipeline connections | Used in specific pipeline sections |
| Pipe Body Saddle-type Pipe Clamp | Provides overall support and sealing | Applied along the length of the pipeline |
The structure of the saddle-type pipe clamp is optimized to ensure efficient performance and easy installation. The materials used, such as nodular cast iron, offer excellent mechanical properties and durability.
III. Lost Foam Casting Process for Saddle-type Pipe Clamps
The lost foam casting process is employed for manufacturing the saddle-type pipe clamps, especially for those above DN300. This process offers several advantages, including the ability to produce complex shapes with high precision and good surface finish.
During the lost foam casting process, a foam pattern of the pipe clamp is created and coated with a refractory material. The coated pattern is then placed in a sand mold, and molten metal is poured into the mold, replacing the foam and taking the shape of the pipe clamp. The process parameters, such as pouring temperature and vacuum degree, are carefully controlled to ensure the quality of the castings.
| Process Parameter | Requirements | Impact on Castings |
|---|---|---|
| Pouring Temperature | Controlled at 1510 – 1530 °C | Affects the fluidity and solidification of the molten metal |
| Vacuum Degree | Minimized while ensuring no mold expansion | Influences the compaction of the sand and the surface quality of the castings |
The use of the lost foam casting process allows for the production of saddle-type pipe clamps with consistent quality and improved mechanical properties.
IV. Properties and Performance of Nodular Cast Iron
Nodular cast iron is the material of choice for the saddle-type pipe clamps due to its superior properties. It offers high strength, good toughness, and excellent corrosion resistance, making it suitable for demanding pipeline applications.
The mechanical properties of nodular cast iron, such as tensile strength and hardness, can be tailored by adjusting the composition and heat treatment processes. This ensures that the saddle-type pipe clamps meet the required performance standards.
| Property | Specification | Importance |
|---|---|---|
| Tensile Strength | Depending on the composition and heat treatment | Ensures the structural integrity of the pipe clamps |
| Hardness | Controlled within a specific range | Affects the wear resistance and durability of the clamps |
The corrosion resistance of nodular cast iron helps to extend the service life of the pipe clamps, reducing maintenance costs and ensuring the reliability of the pipeline system.
V. Type Testing and Quality Assurance
To ensure the quality and performance of the saddle-type pipe clamps, rigorous type testing is conducted. The type test scheme follows relevant standards, such as “GB/T 13295 – 2019,” to evaluate the structural integrity and sealing performance of the pipe clamps.
During the type test, the pipe clamps are subjected to various tests, including pressure testing, to simulate real-world operating conditions. The test results are carefully analyzed to ensure that the pipe clamps meet the specified requirements and can perform reliably in pipeline systems.
| Test Item | Test Method | Acceptance Criteria |
|---|---|---|
| Pressure Testing | Increase the pressure to a specified level and hold for a certain time | No leakage or deformation |
Quality assurance measures are implemented throughout the manufacturing process to ensure the consistency and reliability of the saddle-type pipe clamps. This includes strict control of the raw materials, monitoring of the casting process, and final inspection of the finished products.
VI. Application Examples and Benefits
The saddle-type pipe clamps have been successfully applied in multiple pipeline projects, demonstrating their effectiveness and reliability. They have proven to be particularly useful in situations where quick and efficient pipeline repairs are required, such as in emergency situations or during maintenance work.
The benefits of using the saddle-type pipe clamps include easy installation, which reduces labor intensity and installation time. They also provide a reliable seal, preventing water leakage and ensuring the smooth operation of the pipeline system. Additionally, the use of nodular cast iron ensures the durability of the pipe clamps, reducing the need for frequent replacements and saving costs in the long run.
| Benefit | Description | Impact |
|---|---|---|
| Easy Installation | Simple clamping and nut tightening process | Reduces labor and time required for installation |
| Reliable Sealing | Effective prevention of water leakage | Ensures the integrity of the pipeline system |
| Durability | Long service life of nodular cast iron | Reduces maintenance and replacement costs |
The application of the saddle-type pipe clamps has improved the efficiency and reliability of pipeline systems, contributing to the smooth operation of various industries and infrastructure.
VII. Future Developments and Trends
Looking ahead, there are several potential developments and trends in the field of saddle-type pipe clamps and related pipeline components. Advances in materials science may lead to the development of even more advanced and durable materials for pipe clamps. Additionally, improvements in manufacturing processes, such as the further optimization of the lost foam casting process, could enhance the quality and productivity of pipe clamp production.
The increasing demand for sustainable and environmentally friendly solutions may also drive the development of pipe clamps with better energy efficiency and reduced environmental impact. Furthermore, the integration of smart technologies, such as sensors and monitoring systems, into pipe clamps could enable real-time monitoring of pipeline conditions and early detection of potential issues.
VIII. Conclusion
The development and application of the nodular cast iron saddle-type pipe clamp by lost foam casting represent a significant advancement in pipeline technology. These pipe clamps offer a reliable and efficient solution for pipeline connections and repairs, meeting the demands of modern infrastructure. The combination of the lost foam casting process and nodular cast iron provides excellent mechanical properties, durability, and ease of installation.
Through continuous research and development, improvements in manufacturing processes, and the adoption of new technologies, the performance and functionality of saddle-type pipe clamps are expected to further enhance in the future. This will contribute to the more efficient and reliable operation of pipeline systems, supporting the sustainable development of various industries and communities.
It is important to note that the selection and application of saddle-type pipe clamps should be based on specific project requirements and engineering standards. Proper installation, maintenance, and periodic inspections are also crucial to ensure the long-term performance and safety of the pipeline system. Overall, the nodular cast iron saddle-type pipe clamp by lost foam casting plays a vital role in modern pipeline engineering and will continue to evolve to meet the changing needs of the industry.
