单波纹管轴向补偿
由一个金属波纹管及两端连接件组成，主要用于吸收轴向压缩和轴向伸长。
metal-expansion-joints
Single Axial Metal Bellows Expansion Joint with Limit Rods
Axial thermal movement compensation / Limit-rod controlled structure / Custom options
The single axial metal bellows expansion joint consists of one bellows element, two end connections and limit-rod assemblies. It is primarily used to absorb axial compression and extension caused by temperature changes in straight pipe runs. The limit rods control the permitted movement range and provide over-travel protection, while anchors, guides and pressure-thrust management must still be confirmed by the piping design.
- Nominal size: 1.5 inch-155 inch (DN32-DN4000).
- Nominal pressure: 0.6 / 1.0 / 1.6 / 2.5 / 4.0 MPa.
- Flange or pipe-end connection options; materials and accessories should be confirmed by order.
This limit-rod axial design still requires proper main anchors, pipe guides and pressure-thrust checks in the piping system.
产品概述
产品概述
Metal Bellows Expansion Joints
Single Axial Metal Bellows Expansion Joint with Limit Rods
A limit-rod controlled metal bellows expansion joint for axial compression and extension in straight pipe runs. It is commonly selected for steam, hot water, district heating and industrial process pipelines where axial thermal movement must be absorbed. The joint itself does not balance pressure thrust, so anchors, guides, movement value, medium, pressure, temperature and end connection must be confirmed during selection.
Limit-rod structure note: This is a single axial metal bellows expansion joint with limit rods. The limit rods control the permitted axial travel and provide over-travel protection. The unit remains primarily intended for axial movement, while pipe anchors, guides and pressure-thrust management must be confirmed by the project piping design. The limit rods should not be assumed to continuously carry all normal pressure thrust, and this unit is not a pressure-balanced expansion joint. Rod gap, nut position, rod diameter, allowable load and abnormal-load duty are pending manufacturer drawing confirmation.
Product Photos And Structure Identification
The following images support product identification, structure review, and purchasing communication. If the external rods are limit or transport protection parts, their final function should be confirmed by factory drawing.
Application Scope And Design Boundary
A single axial metal bellows expansion joint is used in straight pipe runs where main anchors and pipe guides have already been considered. It absorbs compression or extension along the pipe axis. It is not a pressure-balanced joint and it is not the preferred solution for large lateral or angular movement. If the piping system has no reliable anchor points, the system design must be reviewed before selection.
Main Use
Axial thermal movement compensation in straight runs of steam, hot water, heating and industrial process pipelines.
System Condition
The pipe run should have main anchors, guides, confirmed installation length and a calculated movement value.
Not Recommended
Long unanchored pipe runs, major lateral movement, or systems that require the joint itself to balance pressure thrust.
Structure And Working Principle
The standard single axial structure normally consists of one metal bellows element and two end connections. The bellows compresses or extends along the pipeline axis to absorb the length change caused by temperature variation. End connections may be flanged, welded or pipe-end type. Internal sleeves, external covers and shipping restraints are order-dependent and should not be described as standard unless confirmed.
When the pipe heats up, the straight run may push toward the expansion joint and compress the bellows. When the pipe cools or movement reverses, the bellows may extend. Pressure thrust is not cancelled by an single axial expansion joint with limit rods joint and must be resisted by the anchors.
Engineering note: local legacy images show external limit rods. If the rods are permanent limit or load-carrying parts, the product should be renamed and selected as a tied or limited design. If they are shipping restraints only, the installation instruction must confirm whether they are removed or retained.
Product Features And Engineering Value
Focused Axial Compensation
Concentrates pipe length change in a calculated location and helps reduce thermal movement transmitted to pumps, valves, equipment nozzles or rigid connections.
Clear Structure Boundary
The single-bellows construction is specified by size, pressure, temperature, movement and installation length, without mixing tied, hinged or pressure-balanced structures into this standard product.
Flexible End Connections
Flanged ends support easier removal and replacement. Weld ends suit permanent pipeline connections. Sealing face, drilling, weld preparation and covers should follow the confirmed drawing.
Parameters Required For Selection
| Size And Connection | DN / NPS, pipe outside diameter, installation length, flange standard, sealing face, bolt holes and weld-end dimensions. |
|---|---|
| Operating Conditions | Design pressure, working pressure, design temperature, working temperature, medium, corrosion condition, insulation and external environment. |
| Product Performance | Axial compression, axial extension, effective area, spring rate, fatigue-cycle requirement, internal sleeve and external cover. |
| Project Requirements | Anchor position, pipe-guide arrangement, equipment nozzle limits, installation direction, inspection standard, quantity, destination port and required documents. |
Materials And Optional Configurations
| Main Part | Selection Basis | Current Status |
|---|---|---|
| Metal bellows / body | Medium, temperature, pressure, corrosion and fatigue cycles | SS304 / 316L, final grade by order |
| End flanges or pipe ends | Pipeline standard, pressure class, sealing face and welding requirement | Stainless steel / carbon steel / alloy options, final material by order |
| Internal sleeve | Flow velocity, erosion, flow direction and pressure-drop concern | Optional; engineering confirmation required |
| External cover | Site protection, insulation, safety and transport protection | Optional; engineering confirmation required |
| Shipping bar or limit rod | Transport protection or special limit requirement | Local image conflict; manufacturer confirmation required |
Production Capability
| Nominal Size | 1.5 inch-155 inch (DN32-DN4000) | Nominal Pressure | 0.6 / 1.0 / 1.6 / 2.5 / 4.0 MPa |
|---|---|---|---|
| Compensation | 18-400 mm | Maximum Temperature | -40-450 °C |
| Connection Type | Flange, pipe | Flange Material | Stainless steel / carbon steel / alloy |
| Flange Standard | ANSI / DIN / EN / JIS | Body Material | SS304 / 316L |
Main Technical Parameters
Each pressure-rating column uses the format "axial compensation mm / spring rate N/mm". Detailed data above DN400 should be confirmed by drawing or manufacturer datasheet.
| DN | Corrugations | 0.25 MPa | 0.6 MPa | 1.0 MPa | 1.6 MPa | 2.5 MPa | Effective Area cm2 | Max. OD mm |
|---|---|---|---|---|---|---|---|---|
| 32 | 8 | 25 / 21 | 22 / 26 | 20 / 26 | 18 / 63 | 15 / 98 | 16 | 110 |
| 40 | 8 | 25 / 28 | 22 / 44 | 20 / 44 | 18 / 89 | 15 / 106 | 23 | 130 |
| 50 | 8 | 30 / 25 | 22 / 51 | 20 / 70 | 18 / 70 | 15 / 138 | 37 | 150 |
| 65 | 8 | 33 / 28 | 30 / 35 | 26 / 44 | 22 / 55 | 19 / 68 | 55 | 170 |
| 80 | 8 | 40 / 20 | 36 / 26 | 34 / 33 | 28 / 41 | 24 / 54 | 81 | 200 |
| 100 | 8 | 45 / 47 | 45 / 60 | 40 / 75 | 35 / 93 | 29 / 117 | 121 | 220 |
| 125 | 6 | 48 / 38 | 42 / 47 | 38 / 59 | 34 / 74 | 29 / 92 | 180 | 250 |
| 150 | 6 | 49 / 42 | 44 / 50 | 40 / 62 | 34 / 78 | 29 / 97 | 257 | 250 |
| 200 | 6 | 52 / 49 | 46 / 55 | 42 / 68 | 38 / 78 | 34 / 111 | 479 | 300 |
| 250 | 6 | 72 / 30 | 63 / 34 | 59 / 42 | 52 / 45 | 47 / 55 | 769 | 300 |
| 300 | 6 | 72 / 51 | 65 / 55 | 59 / 59 | 52 / 65 | 47 / 71 | 1105 | 340 |
| 350 | 6 | 72 / 58 | 65 / 62 | 59 / 67 | 52 / 74 | 47 / 81 | 1307 | 340 |
| 400 | 6 | 75 / 60 | 72 / 70 | 72 / 65 | 60 / 80 | 55 / 90 | 1430 | 380 |
Application Areas
Steam and condensate pipelines: installed in straight heated pipe runs to absorb axial thermal movement.
District heating and hot-water systems: used in heating networks, heat-exchange stations and long hot-water pipelines.
Chemical and industrial process lines: suitable for straight process piping with defined medium, temperature and pressure.
Pump-station or equipment-adjacent straight runs: absorbs axial thermal movement when allowed by engineering design.
Installation And Use Requirements
Before installation, check the drawing, flow direction, installation length, end connection, anchor arrangement and guide arrangement. A single axial expansion joint does not act as the main anchor of the piping system and must not be installed in an unanchored run.
- Confirm pipeline alignment before installation and avoid forced stretching, compression or torsion.
- Confirm that main anchors and pipe guides are installed according to the engineering design.
- If the joint has shipping bars or limit rods, follow the manufacturer's instruction on whether to remove or retain them.
- Pressure test, flushing, insulation and commissioning checks should follow the project drawing, quality plan and manufacturer instruction.
Quality Control And Inspection
Dimension And Visual
Check installation length, end dimensions, flange drilling, bellows appearance, surface protection and marking.
Weld Or Seal Areas
Check transition areas between bellows, end rings and pipe ends according to the order quality plan.
Performance Test
Confirm pressure, leakage, movement or action-related tests by project requirement; do not publish an unconfirmed test pressure.
Packing And Shipment
Confirm end protection, shipping restraint, wooden case or pallet packing, documents and shipping marks.
Custom Design And Quotation
DN / NPS, installation length, end connection, flange standard, bellows material, internal sleeve, external cover, surface treatment, packing and documents can be confirmed according to project data.
For quotation, please provide product name, pipe size, pressure, temperature, medium, axial movement, connection standard, installation length, material requirement, quantity, destination port and any drawing or site photo.
FAQ
How is it different from a tied expansion joint?
A standard single axial joint mainly absorbs axial compression and extension, and it does not balance pressure thrust. Tie rods or limit rods change the force boundary, so the product name and selection should be confirmed if permanent rods are present.
Can it absorb lateral movement?
Its primary function is axial movement. If the pipeline has significant lateral movement, a universal, double-bellows or other engineered design is usually more appropriate.
Who handles pressure thrust?
In an single axial expansion joint with limit rods design, pressure thrust should be resisted by the main anchors and the piping system design, not by the bellows element itself.
Should I choose flanged ends or weld ends?
Flanged ends are easier to remove and replace. Weld ends are suitable for permanent pipeline connections. Confirm pipeline standard, pressure class, sealing face, space and maintenance strategy.
Related Products
External-Pressure Axial Expansion Joint
Used when longer axial movement, stability or an external-pressure arrangement is required.
Universal Metal Bellows Expansion Joint
More suitable when lateral movement is the main requirement in the pipeline layout.
Single Hinged Expansion Joint
Considered when angular rotation and hinge-controlled load restraint are needed.
Straight-Pipe Pressure-Balanced Expansion Joint
Considered where the piping system cannot accept high pressure thrust, with different space and cost implications.
Bellows And Connection Details
Before ordering, confirm movement, pressure class, temperature, flange standard, material, and installation length instead of replacing only by appearance.
Typical Application Scenes
Application images show common installation positions. Final suitability depends on medium, pressure, temperature, pipeline movement, and support design.
Installation And Alignment Check
Single axial metal bellows expansion joints are normally used with anchors and guides. Site installation should follow project drawings and instructions.
Quality Inspection And Export Packing
These images cover dimensional inspection and export packing. Pressure testing, material documents, certificates, and packing grade should be confirmed by order.
结构组成与工作原理
结构组成与工作原理
产品通过金属波纹管沿管道中心轴线的压缩与伸长吸收轴向位移，适用于运动方向明确的直线管段。
基础结构组成
轴向补偿原理
管道受热伸长或收缩时，波纹管通过轴向压缩或伸长吸收位移。管道运动应尽量沿产品中心轴线传递。
压力推力提示：
本产品不用于平衡管道压力推力，固定支座、导向支架及系统受力应根据实际工况确认。
产品特点
产品特点
产品主要面向运动方向明确的直线管段，其使用效果同时取决于膨胀节结构、实际位移及管道系统条件。
运动方向便于控制
配合适当的固定和导向结构，可将主要管道运动控制在产品中心轴线方向。
连接结构可选
可根据管道标准、施工条件和维护要求选择法兰端、管端或定制连接结构。
按项目工况设计
尺寸、材料、位移能力、轴向刚度、附件和检验要求需根据实际工况确认。
选型边界： 存在较大横向位移、角位移、复杂组合位移或压力推力平衡要求时，应评估其他类型的膨胀节结构。
技术规格与选型
技术规格与选型
参考尺寸仅供选型。可根据项目定制尺寸和法兰标准。
| 公称直径范围 | DN32–DN4000 |
|---|---|
| 公称压力等级 | 0.25 / 0.6 / 1.0 / 1.6 / 2.5 / 4.0 MPa |
| 轴向补偿量 | 18–400 mm |
| 可选设计温度范围 | -40℃至450℃ |
| 连接形式 | 法兰端／管端，具体结构按确认图纸 |
| 法兰材料 | 不锈钢／碳钢／合金 |
| 法兰标准 | 可按 ASME、EN、DIN、JIS 等项目指定标准生产，具体标准号、压力等级及密封面形式按订单确认。 |
| 波纹管／主体材料 | 常用波纹管材料为 SS304、SS316L，其他材料可根据介质、设计温度、腐蚀条件及项目要求确认。 |
DN32–DN400常用规格参数
压力等级单元格中的数据格式为： 轴向补偿量（mm）／轴向刚度（N/mm）。
| 公称直径 DN | 波纹数量 | 公称压力等级（MPa） | 有效面积 cm² | 最大外径 mm | ||||
|---|---|---|---|---|---|---|---|---|
| 0.25 | 0.6 | 1.0 | 1.6 | 2.5 | ||||
| 32 | 8 | 25/21 | 22/26 | 20/26 | 18/63 | 15/98 | 16 | 110 |
| 40 | 8 | 25/28 | 22/44 | 20/44 | 18/89 | 15/106 | 23 | 130 |
| 50 | 8 | 30/25 | 22/51 | 20/70 | 18/70 | 15/138 | 37 | 150 |
| 65 | 8 | 33/28 | 30/35 | 26/44 | 22/55 | 19/68 | 55 | 170 |
| 80 | 8 | 40/20 | 36/26 | 34/33 | 28/41 | 24/54 | 81 | 200 |
| 100 | 8 | 45/47 | 45/60 | 40/75 | 35/93 | 29/117 | 121 | 220 |
| 125 | 6 | 48/38 | 42/47 | 38/59 | 34/74 | 29/92 | 180 | 250 |
| 150 | 6 | 49/42 | 44/50 | 40/62 | 34/78 | 29/97 | 257 | 250 |
| 200 | 6 | 52/49 | 46/55 | 42/68 | 38/78 | 34/111 | 479 | 300 |
| 250 | 6 | 72/30 | 63/34 | 59/42 | 52/45 | 47/55 | 769 | 300 |
| 300 | 6 | 72/51 | 65/55 | 59/59 | 52/65 | 47/71 | 1105 | 340 |
| 350 | 6 | 72/58 | 65/62 | 59/67 | 52/74 | 47/81 | 1307 | 340 |
| 400 | 6 | 75/60 | 72/70 | 72/65 | 60/80 | 55/90 | 1430 | 380 |
数据说明： 详细表列出DN32至DN400、0.25至2.5 MPa常用规格。4.0 MPa及DN450以上产品的补偿量、刚度、有效面积和外形尺寸，应根据具体型号另行确认。
应用领域
应用领域
该产品主要用于能够通过固定和导向系统控制轴向运动的直线管段。具体适用性仍需结合介质、压力、温度、位移和管道受力条件确认。
蒸汽与热水管道
用于工业供热、蒸汽、热水及换热系统直线管段的轴向热位移补偿。
电力与能源设施
适用于电厂及能源项目中具备合理固定、导向和支撑条件的辅助工艺管道。
石油化工装置
用于经过介质、压力、温度、腐蚀条件和疲劳要求评审的工艺管线。
钢铁与冶金管路
可用于重工业设施中的热力、工业气体及辅助工艺管线。
应用说明： 行业名称仅用于说明典型应用，具体项目是否适用应以实际工况和技术选型结果为准。
安装使用
安装使用
产品应安装在经过设计的管道系统中。安装前应核对产品状态、连接条件和管道布置，避免将安装误差、扭转载荷或其他非设计载荷传递给波纹管。
核对产品与连接条件
检查产品是否存在运输损伤，并核对连接方式、安装位置和安装空间。
避免强制对口
不得通过强行压缩、拉伸或扭转膨胀节来修正管道安装误差。
防止波纹管损伤
应防止工具、吊具、焊渣、电弧及其他硬物损伤薄壁波纹管。
核查固定与支撑
系统试验和投运前，应依据管道图纸检查固定、导向、支撑及连接状态。
安装说明： 支架位置、安装长度、预变形、紧固要求、运输固定件处理及系统试验程序，以最终确认的产品图纸和安装说明为准。
质量控制
质量控制
实际检验项目应依据产品结构、订单要求和订单质量计划确定。不同订单的检测范围可能不同。
尺寸与外观检查
核查安装长度、连接尺寸、整体装配状态，并对关键连接部位和焊缝外观进行检查。
性能试验
是否进行压力、密封或其他性能试验，应根据订单和产品要求确认。
包装与出货检查
对连接端、波纹管及附件进行适当保护，降低运输和装卸损伤风险。
材料文件、无损检测、性能试验、第三方检验和其他交付文件是否提供，应以订单确认内容为准。
常见问题
常见问题
1. What is a Single Axial Metal Bellows Expansion Joint?⌄
A Single Axial Metal Bellows Expansion Joint is a flexible pipeline component that uses metal bellows to absorb axial thermal movements caused by temperature changes.
2. Where are Single Axial Expansion Joints commonly used?⌄
They are widely used in petrochemical plants, power generation facilities, heating networks, industrial pipelines and equipment connection systems.
3. What type of movement can this expansion joint absorb?⌄
This type of expansion joint is mainly designed for axial movement compensation, absorbing pipeline expansion and contraction along the pipe axis.
4. How do I select the correct expansion joint?⌄
Selection requires information including pipe size, pressure, temperature, medium, movement requirements, connection standard and installation conditions.
5. Can you manufacture customized expansion joints?⌄
Yes. Customized solutions can be provided according to dimensions, materials, pressure ratings, connection types and project requirements.
6. What materials are available for metal bellows expansion joints?⌄
Material selection depends on operating temperature, pressure, corrosion conditions and application requirements. Suitable stainless steel materials can be selected according to specific working conditions.
7. What information is required for quotation?⌄
Customers should provide pipe diameter, operating conditions, movement requirements, connection details and related technical drawings if available.
8. Can you provide inspection documents and quality certificates?⌄
Yes. Quality documents, inspection records, material certificates and other project-related documents can be provided according to customer
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