Union Fitting
Union Fitting vs Ordinary Straight Coupling Comparison
Conventional straight coupling connects two pipe ends permanently. Once assembled, to disassemble downstream pipeline or equipment, adjacent pipe segments have to be cut off, which brings high maintenance cost and construction difficulty.
Three-piece union fitting integrates nut, male-end and female-end. It creates a detachable pipe joint. Without cutting the pipe, technicians can quickly separate two sides of pipeline for equipment removal, inspection or component replacement. It greatly improves maintainability for equipment-connected points.
|
Item |
Ordinary Permanent Straight Coupling |
Union Fitting (This Product) |
|
Disassembly requirement |
Must cut pipe for separation |
Detachable without pipe cutting |
|
Component composition |
Single-piece body |
Three-piece assembly: nut, male-end, female-end |
|
Gasket sealing |
No independent replaceable gasket |
Interchangeable gasket-based static seal |
|
Maintenance workload |
High for equipment overhaul |
Low, convenient for repeated disassembly |
|
Available connection |
Mainly threaded |
Threaded / socket-weld dual options |
|
Typical usage |
Fixed non-serviceable pipeline sections |
Joint beside valves, meters, terminal equipment |
Product Overview
Yuanlun union fitting is a three-piece detachable pipeline connector, also known as union connector. Assembly consists of three core components: compression nut, male-end (cloud-head) and female-end (flat-seat joint). Two connection versions are available: threaded type and socket-weld type.
Compression nut pulls male-end and female-end tightly together; replaceable gasket (rubber / rubber-asbestos sheet) is clamped between two sealing faces to realize static leak-proof sealing. Brass material delivers high mechanical strength and pressure resistance. It is widely adopted in plumbing, HVAC and light-industrial piping where repeated disassembly for maintenance is required.
Important note: Installation recommended to be completed by qualified plumbing technicians. Gasket material shall be selected according to actual working medium and temperature. Do not over-tighten the union nut; excessive torque will crush gasket or damage brass thread.
Key Advantages
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Three-Piece Detachable Structural Design
Modular assembly made up of nut, male-end and female-end. Pipeline or equipment can be separated conveniently without cutting pipe segments, perfectly suited for positions requiring regular inspection, replacement or maintenance.
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Dual Connection Form Availability
Two configurable connection styles: threaded for screw-in assembly; socket-weld for welding insertion. Flexible to match different on-site pipe configuration and installation process requirements.
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High-Strength Robust Brass Material
Adopt premium brass raw material. Outstanding pressure-bearing capacity and mechanical durability, stable performance under complex working-condition environments.
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Replaceable Gasket Static-Sealing System
Sealing relies on intermediate gasket (rubber or rubber-asbestos sheet). When ageing or leakage occurs, only the gasket needs to be swapped out, no requirement to replace the whole union fitting, lowering spare-part cost.
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Stable Installation Performance Independent of Operator Skill Level
Standardized assembling workflow. Joint sealing performance does not heavily depend on installer personal experience, effectively reducing human-caused assembly mistakes and improving joint reliability consistency.
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Excellent Pressure-Resistant & Leak-Proof Properties
Make full use of base-material ductility and mechanical strength, comply with industry performance standards. Reliable leak-proof performance under pressure-fluctuation operating conditions.
|
Feature |
Description |
|
Place of origin |
China |
|
Brand name |
Yunnl |
|
Product Name |
Union Fitting |
|
Size |
DN15-DN50 |
|
Sealing Gasket |
Rubber / rubber-asbestos sheet, replaceable spare-part |
|
Connection Type |
Threaded (ISO228 BSP standard, NPT optional) / Socket-weld |
|
Nominal Pressure |
PN16 (1.6 MPa) |
|
Working Temperature |
5℃ ~ 90℃ (subject to gasket material variant) |
|
Applicable Medium |
Cold-hot water, non-corrosive liquid, compatible media matching gasket grade |
|
Minimum Order Quantity |
1 |
|
Price |
Negotiable |
|
Packing |
Yuanlun standard packing |
|
Payment Terms |
L/C, D/A, D/P, T/T, Western Union, MoneyGram |
|
Delivery Time |
15 Days |
How Union Fitting Works
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Main Components & Function
|
Component |
Core Function |
|
Compression nut |
Apply axial tightening force, pull male-end and female-end together |
|
Male-end (cloud-head) |
One-side pipe connection, provides convex sealing mating face |
|
Female-end (flat-joint) |
Opposite-side pipe connection, provides flat gasket seating face |
|
Intermediate gasket |
Compressed between two metal faces to form static leak-proof seal |
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Operating Principle
Mount male-end and female-end respectively onto two opposite pipeline / equipment ports.
Place qualified matched gasket flatly on the female-end sealing seating surface. Gasket must sit fully flat without offset or wrinkle.
Screw compression nut onto male-end thread. As nut tightens, it pulls male-end towards female-end.
Axial tightening force compresses intermediate gasket, forming static sealing between two metal faces to block medium leakage.
For disassembly: simply unscrew compression nut; two pipe-sides can be separated directly without pipe cutting.
Operating reminder: Gasket must be correctly matched to medium and temperature. Over-torque will crush gasket and cause early-stage leakage.
Application Scenarios
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Residential & Commercial Plumbing Systems
Use-case: Detachable joints beside water meters, filters, water-heater terminals. Project value: Convenient disassembly for equipment overhaul and component replacement without pipe cutting.
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HVAC Heating & Chilled-Water Pipelines
Use-case: Connecting joints near ball valves, angle valves and manifold peripherals. Project value: Simplify valve maintenance and removal work inside compact manifold cabinets.
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Light-Industrial Process Piping
Use-case: Detachable connection for process-equipment inlet-outlet ports. Project value: Threaded / socket-weld two options adapt different industrial-site construction requirements.
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Garden & Landscape Pipe Networks
Use-case: Quick-disconnect joints for garden-pipe branch and auxiliary equipment. Project value: Easy on-site assembly and disassembly for seasonal pipeline reconstruction.
Installation Guide
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Pre-Installation Check
Confirm union size, connection-type (threaded / socket-weld) match on-site pipe specification. Select gasket material suitable for medium and temperature.
Inspect sealing faces of male-end and female-end; remove burr, dirt and old gasket residue. Damaged sealing-face cannot be used.
For threaded-type: Clean pipe-thread, remove debris.
For socket-weld-type: Prepare welding equipment, ensure insertion depth meets welding-process requirement.
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Installation Steps
Threaded-type Union
Wind PTFE-tape 3-5 clockwise turns and mount male-end and female-end onto respective pipe ports. Tighten on body flats; do not apply torque on compression nut.
Lay new intact gasket flat on female-end sealing seat, keep gasket centered without skew.
Manually screw compression nut onto male-end thread until gasket contacts sealing-faces.
Apply moderate additional wrench torque on compression nut. Strictly avoid over-tightening to prevent gasket crushing or brass-thread damage.
Complete assembly, slowly pressurize system and perform joint leakage inspection.
Socket-Weld-type Union
Insert male-end and female-end into corresponding pipe ends to specified insertion depth, complete welding operation. Allow weldment to fully cool down.
After cooling, place matched gasket onto female-end sealing seat.
Screw compression nut and tighten with proper torque. Carry-out pressure-leakage test.
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Important Installation Notes
Installation recommended for qualified plumbing technicians.
Always use brand-new gasket for reassembly after disassembly; reused aged gaskets easily cause leakage.
Do not over-torque compression nut.
Gasket material must be compatible with system medium and operating temperature.
Maintenance & Troubleshooting
|
Phenomenon |
Probable Root-Cause |
Recommended Solution |
|
Union-joint leakage |
Gasket ageing / damage; gasket offset / wrinkle; insufficient nut torque; scratched metal sealing-face |
Disassemble fitting; replace with brand-new matched gasket; clean or repair sealing-face; retighten nut to proper torque |
|
Thread-port leakage (threaded-version) |
Insufficient PTFE-tape; thread scratch / damage |
Re-apply sealing-tape; replace damaged union component |
|
Compression nut cannot turn smoothly |
Thread contaminated with scale and dirt |
Clean thread surface; apply compatible thread-lubricant |
Routine-Maintenance Suggestion
Visual leakage inspection of union joint: Quarterly
When pipeline equipment is disassembled for overhaul: Must replace sealing gasket with new spare-part
Visual inspection for sealing-face scratch and thread damage: Annually
FAQ
Q: How long is your product guarantee period?
A: We have three-year guarantee and 24 hours full-time service.
Q: What is your MOQ?
A: We have no MOQ. We have a large warehouse and we promise "Instant Order, Immediate Delivery and No MOQ".
Q: Can you accept OEM and ODM?
A:Yunnlaccepts OEM and ODM partnerships.
Q: How long is your delivery time?
A: For the items if we have enough stocks, we can send to you immediately. For mass production, we can promise 30-35 days.
Q: Can I reuse the old gasket after disassembling union fitting?
A: Not recommended. After compression, gaskets produce permanent deformation. Reuse will bring high leakage risk. Always install brand new gasket during reassembly.
Q: Can socket weld union be disassembled after welding?
A: Yes. Only the union nut gasket sealing joint is detachable. Welded ends are permanently fixed to the pipe.
Q: Can union fitting be used for steam?
A: Standard rubber / rubber asbestos gasket is not suitable for steam service. Special high temperature gasket variant must be specified when ordering for steam working condition.
Products Summary
Yuanlun three-piece brass union fitting is detachable pipeline connector, available in threaded or socket-weld connection forms, PN16 pressure-rating, DN15-DN50 size-range. Replaceable gasket static-sealing structure enables pipeline disassembly without pipe-cutting, greatly facilitating equipment maintenance and component replacement. Widely-used for plumbing, HVAC, garden piping and light-industrial non-corrosive-fluid piping-systems. 3-year product guarantee is provided; OEM/ODM customization available. Sample-order supported for pre-project-evaluation; in-stock goods for immediate shipment, 30-35-day lead-time for mass-production bulk-orders, serving worldwide plumbing-HVAC distributors and engineering-contractors.
Factory Information
Zhejiang Yuanlun Valve Co., Ltd. was founded in 2006, formerly known as Yuhuan Guohong Valve Co., Ltd. It is located in Yuhuan, Zhejiang Province, known as the "Valve Capital of China". After nearly two decades of stable development, Yuanlun Valve is a professional manufacturer for HVAC valves integrating R&D, production and sales. Our product portfolio covers floor heating systems, air-conditioning systems, domestic water valves, including ball valves, thermostatic valves, manifolds, check valves, stop valves, filter valves, angle valves, pipe fittings, corrugated pipes and other series.
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