Different Diameter Direct Sliding Fasteners

Ordinary equal-diameter direct sliding fastener is only for pipes with identical outer diameter. When pipeline needs straight-line size transition, it must be matched with extra separate reducer fitting, which adds intermediate joints and increases potential leakage-points.

Different-diameter direct sliding fastener (reducing straight slide-tight coupling) integrates two different-size slide-tight ports in one straight-shaped body. It can directly connect two pipes of dissimilar outer-diameters in straight pipeline runs. Eliminates extra independent reducer fitting, reduces joint quantity for straight-run mixed-diameter pipe transition layout.

Yuanlun different-diameter direct sliding fastener (reducing straight slide-tight coupling) is straight-type slide-tight pipeline coupling, specially used for straight-line connection of two pipes with dissimilar outer-diameters, realizing diameter transition in one fitting.

Adopts pipe-material memory-effect assisted sealing principle. Compact body-structure, cost-effective. Complies with GB/T 22051-2008 national standard. Nominal pressure PN16 (1.6 MPa), working-temperature range 5℃-90℃, long-term service up to 95℃ for heating-system conditions. Requires dedicated flaring-tool and slide-tight pliers for on-site assembly. Widely-used for building plumbing, floor-heating and light-industrial non-corrosive-liquid piping-systems.

Important note: Installation recommended to be completed by qualified plumbing technicians. Strictly follow two-pass flaring process; keep 3-4 mm reserved insertion gap; mismatched tools or non-standard flaring will cause hidden leakage risk.

• Yuanlun Sliding-Tension Pipe-Connection Technology

Sealing relies on memory-rebound property of pipe material itself. Compact fitting-body, realizes safe and stable pipe connection. Fast on-site assembly, cost-effective with neat pipeline appearance.

• High-Temperature Resistant Performance

Capable of long-term continuous operation up to 95℃, well-suited for household floor-heating and hot-water heating-system working-conditions.

Specifications

• Standards Compliance: GB/T 22051-2008
• Nominal Pressure: 1.6 MPa
• Temperature Range: 5℃ ≤ t ≤ 90℃, long-term heating-system working condition up to 95℃

• Main Components & Function

• Operating Principle

1. Complete two-pass flaring-treatment on pipe-end by flaring-tool; pipe mouth forms uniform flared profile.
2. Insert fitting main-body into flared pipe-end and keep specified 3-4 mm assembly gap.
3. Position sliding-tension ring onto pipe outer-wall, apply pressure via dedicated slide-tension pliers to push sliding-tension ring to designated position.
4. Sliding-tension ring produces radial compression force. Combined with memory-rebound effect of flared pipe-end material, reliable mechanical locking and leak-proof sealing are formed for different-diameter straight-run connection.
5. Operating reminder: This fitting requires mandatory pre-flaring for pipe-end. Skipping flaring-procedure will lead to complete sealing-failure. Two-pass flaring process shall be strictly followed.

• Floor-Heating & Household Hot-Water Systems

Use-case: Straight-line pipe-diameter transition for heating-loop and domestic hot-water pipelines. Project value: High-temperature-resistant performance adapts long-term heating-system circulating-water environment, single-fitting replaces separate reducer.

• Building Cold-Hot-Water Supply-Systems

Use-case: Straight-run size transition points for indoor plumbing renovation projects. Project value: Compact-structure, reduces intermediate fitting quantity for mixed-size pipe layout.

• Light-Industrial Non-Corrosive-Liquid Piping

Use-case: Straight-through different-diameter connection for plastic composite-pipe process pipelines. Project value: Complies with GB/T22051-2008 standard, stable performance for general-purpose non-corrosive-medium.

• Flaring Operation

Slide the sliding tension ring onto the pipe and rotate it evenly for flaring. Handheld flaring tools or flaring pliers used in conjunction with sliding tension pliers can be adopted. Typically, flaring requires two passes. During the second pass, slightly rotate the pipe to ensure uniform flaring.

• Fitting Insertion

Insert the main body of the fitting into the pipe, leaving a gap of 3–4 mm.

• Sliding Tension Connection

Fix the pipe with sliding tension tools, push the sliding tension ring into place, and complete the installation by applying pressure.

• Pre-Installation Check

1. Confirm two-port dimension of different-diameter direct sliding fastener matches outer-diameter of two connected pipes. Prepare matched flaring-tool and slide-tension pliers.
2. Inspect fitting-body and sliding-tension ring; reject cracked, deformed or damaged components.
3. Square-cut pipe-end, remove all burrs and sharp edges. Burr will affect flaring quality and final sealing-performance.

• Installation Steps

1. Put sliding-tension ring onto pipe outer-wall in advance.
2. Perform two-pass flaring-process with flaring-tool; rotate pipe slightly on second pass to guarantee uniform flared mouth profile.
3. Insert fitting body into flared pipe-end, strictly keep 3-4 mm reserved gap, do not press fitting fully against pipe-flared face.
4. Secure pipe, operate dedicated slide-tension pliers to push sliding-tension ring to final designated position.
5. Repeat above flaring-insert-crimp workflow for the second-different-diameter pipe-end.
6. After whole assembly completion, slowly pressurize system, inspect both slide-tight crimp-joints for leakage.

• Important Installation Notes

1. Installation recommended for qualified plumbing technicians.
2. Pre-flaring process cannot be omitted; strictly implement two-pass flaring requirement.
3. Keep mandatory 3-4 mm gap between fitting body and flared pipe-end; zero-gap assembly causes joint-failure.
4. Each-side port corresponds to dedicated-size flaring-tool and sliding-tension ring; mismatched-size accessories bring hidden-leakage risk.

Routine-Maintenance Suggestion

• Visual inspection of two crimp-joints for leakage: Quarterly
• Check sliding-tension ring locking-state during system overhaul: Annually
• Replace damaged sliding-tension-ring and re-flare pipe-end upon leakage-failure: As-required

Yuanlun different-diameter direct sliding fastener is straight-through reducing slide-tight coupling complying with GB/T 22051-2008 national-standard. PN16 pressure-rating, DN15-DN50 mixed-diameter combinations available. Sealing relies on pipe-material memory-rebound together with sliding-tension-ring compression; pipe-end must perform two-pass pre-flaring and keep 3-4 mm assembly gap. Suitable for long-term heating-system operation up to 95℃. Widely-applied for floor-heating, domestic hot-water supply and light-industrial plastic-composite-pipe straight-run different-diameter transition piping-systems. Sample-order supported for pre-project-evaluation, 15-day standard lead-time for worldwide plumbing-HVAC distributors and engineering-contractors.

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.