Hongze Valve

One-Stop Supplier for Rubber Joints, Bellows, and Waterproof Casings

Rubber Reducer Expansion Joint

The Rubber Reducer, also known as Rubber Reducing Joint, Rubber Eccentric Reducer, or Flexible Reducer Connector, is specially designed to connect pipelines of different diameters. It helps compensate for displacement, reduce vibration, and eliminate installation mismatches. Commonly used in HVAC systems, water treatment plants, and industrial pipelines, it supports both concentric and eccentric structures based on flow needs.

Key Features

• Size Transition – Connects pipelines with different diameters seamlessly.

•Shock & Noise Absorption – Reduces mechanical stress and noise during operation.

•Eccentric & Concentric Options – Available for various flow direction needs.

•Flexible Installation – Easy to align and install in limited spaces.

•Corrosion Resistance – Suitable for water, oil, and weak acid/alkaline media.

•Also Known As – Flexible Reducer, Rubber Eccentric Coupling, Concentric Rubber Joint.

Technical Specifications

Dimensions & Sizes

Nominal Diameter (DN)	Inch	Length (L) mm	Flange Thickness (b) mm	Bolt Qty (n)	Bolt Hole Dia. mm	Bolt Circle Dia. (D1) mm	Axial Extension mm	Lateral Displacement mm	Angular Deflection (°)

DN32×25

1¼”×1″

100

DN40×32

1½”×1¼”

110

DN50×40

2″×1½”

105

125

DN65×50

2½”×2″

115

145

DN80×65

3″×2½”

135

160

DN100×80

4″×3″

150

180

DN125×100

5″×4″

165

210

DN150×125

6″×5″

180

240

DN200×150

8″×6″

210

295

DN250×200

10″×8″

230

350

DN300×250

12″×10″

245

400

Technical Parameters

Project	Unit	CRJ-1	CRJ-2	CRJ-3
Model	–	CRJ-1	CRJ-2	CRJ-3
Working Pressure	MPa (kgf/cm²)	1.0 (10)	1.6 (16)	2.5 (25)
Burst Pressure	MPa (kgf/cm²)	2.0 (20)	3.0 (30)	4.5 (45)
Vacuum Resistance	KPa (mmHg)	53.3 (400)	86.7 (650)	100 (750)
Operating Temperature	°C	-15 ~ 115°C (Special: -30 ~ 250°C)	-15 ~ 115°C (Special: -30 ~ 250°C)	-15 ~ 115°C (Special: -30 ~ 250°C)
Applicable Media	–	Air, Compressed Air, Water, Seawater, Hot Water, Oil, Acid, Alkali, etc.	Air, Compressed Air, Water, Seawater, Hot Water, Oil, Acid, Alkali, etc.	Air, Compressed Air, Water, Seawater, Hot Water, Oil, Acid, Alkali, etc.

Rubber Materials

Material	Temperature Range (°C)	Oil Resistance	Acid & Alkali Resistance	Elasticity	Abrasion Resistance	Typical Applications

EPDM

-40 ~ 120

Poor

Excellent

Medium

Water, Steam, Air

NR (Natural Rubber)

-30 ~ 80

Poor

Medium

Excellent

Industrial Water, Air

NBR

-20 ~ 100

Excellent

Medium

Good

Oil, Lubrication Systems

Neoprene

-35 ~ 100

Good

Medium

Good

Seawater, Mild Chemicals

Silicone

-60 ~ 200

Poor

Good

Low

Food Grade, Medical

FKM (Viton)

-20 ~ 250

Excellent

Medium

Excellent

Chemical, High Temp Oil

Butyl (IIR)

-40 ~ 120

Poor

Good

Excellent

Medium

Gas, Acidic Gases

Installation Guide

1.Inspection Before Installation

•Check whether the rubber joint is damaged, aged, or defective.

•Confirm the model, pressure rating, and flange size match the system requirements.

2.Installation Environment

•Avoid installation under direct sunlight, ozone, or in environments with high temperature or strong corrosive chemicals.

•If outdoor installation is necessary, use UV-protective shields or covers.

3.Installation Instructions

•Align the rubber joint with the center of the pipe flanges. Avoid pulling or twisting during installation.

•Tighten bolts crosswise and evenly to avoid uneven force or deformation.

•Use proper washers and gaskets.

4.Precautions

•Ensure the pipeline is properly fixed; rubber joints are not designed to bear the full weight.

•Do not over-extend, over-compress, or apply excessive torsion to the joint.

•Allow for movement as specified (axial, lateral, angular) within rated limits.

•Install limit rods or anti-pull devices if the pipe system lacks sufficient fixation.

5.Working Pressure & Temperature

•Observe the rated pressure and temperature range during operation.

•Standard range: -15°C to +115°C (or as specified).

6.Routine Inspection & Maintenance

•Inspect every 6–12 months for signs of aging, damage, or leakage.

•Replace if any abnormalities are found.

Maintenance Guide

1. Inspection Before Installation

•Check whether the rubber joint is damaged, aged, or defective.

•Confirm the model, pressure rating, and flange size match the system requirements.

2.Installation Environment

•Avoid installation under direct sunlight, ozone, or in environments with high temperature or strong corrosive chemicals.

•If outdoor installation is necessary, use UV-protective shields or covers.

3.Installation Instructions

•Align the rubber joint with the center of the pipe flanges. Avoid pulling or twisting during installation.

•Tighten bolts crosswise and evenly to avoid uneven force or deformation.

•Use proper washers and gaskets.

4.Precautions

•Ensure the pipeline is properly fixed; rubber joints are not designed to bear the full weight.

•Do not over-extend, over-compress, or apply excessive torsion to the joint.

•Allow for movement as specified (axial, lateral, angular) within rated limits.

•Install limit rods or anti-pull devices if the pipe system lacks sufficient fixation.

5.Working Pressure & Temperature

•Observe the rated pressure and temperature range during operation.

•Standard range: -15°C to +115°C (or as specified).

6.Routine Inspection & Maintenance

•Inspect every 6–12 months for signs of aging, damage, or leakage.

•Replace if any abnormalities are found.

What is a Rubber Reducer Expansion Joint used for?

A Rubber Reducer Expansion Joint is used to connect pipelines of different diameters, compensating for pipe size changes while absorbing vibration and noise. It helps eliminate installation mismatches and improves overall system flexibility.

What types of Rubber Reducer Expansion Joints are available?

We offer both concentric and eccentric rubber reducer expansion joints. Concentric types have a symmetrical shape, while eccentric reducers are offset, making them ideal for systems that require specific flow direction or installation space.

What materials are used for Rubber Reducer Expansion Joints?

Our reducer joints are made from high-quality EPDM, NBR, or custom rubber compounds, with options for stainless steel or carbon steel flanges. The material can be selected according to the working medium, pressure, and temperature requirements.

Can you provide custom sizes and designs for Rubber Reducer Expansion Joints?

Yes, we offer OEM and ODM services. Customized sizes, materials, and flange types are available to meet your specific application needs. Just send us your requirements or drawings for a tailored solution.

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