Pump Vibration & Pipe Noise Driving You Crazy? One Rubber Joint Solves It All.

Function

Description

Pump Vibration Isolation

Installed on pump suction and discharge connections — absorbs pump-generated vibration, preventing it from transmitting through piping to the building structure. Reduces noise and prevents pipe fatigue from constant vibration.

Chiller & Air Handler Connections

Connects chiller evaporator/condenser nozzles to rigid piping — isolates equipment vibration from the building. Compensates for thermal movement of large chiller vessels during start-up and shutdown.

Thermal Expansion Compensation

Absorbs linear expansion of hot water and chilled water piping due to temperature changes — eliminates need for metal expansion loops or bellows in many applications.

Pipe Misalignment Compensation

Allows minor angular, lateral, or axial misalignment during installation — simplifies pipe fitting and reduces stress on flanged connections.

Noise Reduction

The rubber body dampens fluid-borne and structure-borne noise — reduces water hammer noise, pump pulsation noise, and flow turbulence noise transmitted through piping.

Protecting Equipment from Pipe Stress

Isolates pumps, chillers, and valves from pipe settlement, thermal movement, and building shifts — prevents flange bending, nozzle stress, and premature equipment failure.

Application Field

Specific Use

HVAC Chilled Water Systems

Pump suction/discharge isolation, chiller connections, air handler connections, main pipe expansion

HVAC Hot Water Heating

Boiler pump connections, heat exchanger isolation, radiator main expansion, thermal loop compensation

Wastewater Treatment

Pump suction/discharge in lift stations, digester recirculation lines, sludge transfer, blower connections

Tap Water / Potable Water

Pump stations, pressure booster systems, water treatment plant piping, reservoir connections

Cooling Tower Piping

Tower pump connections, basin connections, make-up water lines

Industrial Cooling Systems

Compressor connections, heat exchanger isolation, process cooling loops

Feature

Advantage

GB/T26121-2010 Compliance

Manufactured to Chinese national standard for rubber expansion joints — ensures design integrity, dimensional accuracy, pressure rating, and performance testing for HVAC, water, and wastewater applications.

Exceptional Diameter Range (DN25–DN2000)

Covers everything from small pump connections (DN25) to the largest chiller and wastewater mains (DN2000) — a single product family for all HVAC and water system sizes.

Wide Pressure Range (0.6–2.5 MPa / 6–25 bar)

Suitable for low-pressure gravity systems (0.6 MPa) to medium-high-pressure HVAC and water distribution systems (2.5 MPa) — covers chilled water, hot water, condenser water, and tap water applications.

EPDM Rubber Construction — Excellent Durability

EPDM (ethylene propylene diene monomer) rubber provides exceptional resistance to hot water, chilled water, dilute acids/alkalis, ozone, UV, and weathering — long service life in HVAC and water environments. Temperature range -40°C to +120°C.

Multi-Directional Movement Capability

Absorbs axial compression, axial extension, lateral deflection, and angular rotation simultaneously — accommodates all types of pipe movement from thermal expansion, settlement, vibration, and misalignment.

Vibration & Noise Reduction

The flexible rubber body decouples mechanical vibration and dampens noise transmission — reduces structure-borne noise from pumps and chillers, improves occupant comfort, and protects piping from vibration fatigue.

Movement Type

Description

Typical Amount

Axial Compression

Shortening of the joint length

15–25 mm (depending on size)

Axial Extension

Lengthening of the joint length

10–20 mm (depending on size)

Lateral Deflection

Side-to-side movement perpendicular to pipe axis

15–30 mm (depending on size)

Angular Rotation

Bending at an angle from the pipe axis

15°–35° (depending on size)

Vibration Absorption

High-frequency mechanical vibration

Continuous, unlimited within elasticity

Reason

Benefit

Designed for HVAC & Water Systems

EPDM construction and wide temperature range (-40°C to +120°C) are ideal for chilled water, hot water, condenser water, and tap water service.

GB/T26121-2010 Compliant

Manufactured to recognized Chinese national standard — ensures quality, dimensional accuracy, and pressure rating integrity.

Exceptional Diameter Range (DN25–DN2000)

One supplier for small pump connections to the largest chiller and wastewater mains — consistent quality across all sizes.

Wide Pressure Range (0.6–2.5 MPa)

Suitable for low-pressure gravity lines to medium-high-pressure distribution systems — covers most HVAC and water applications.

Superior Vibration & Noise Reduction

Decouples pump and chiller vibration from piping — reduces structure-borne noise and prevents pipe fatigue.

Multi-Directional Movement

Absorbs axial, lateral, angular, and vibration movement — one device handles all pipe movement needs.

Parameter

Specification

Design Standard

GB/T26121-2010 (Rubber Expansion Joints)

Diameter Range (DN)

DN25 – DN2000 (1" – 80")

Pressure Range

0.6 – 2.5 MPa (6 – 25 bar / 87 – 362 psi)

Medium

Water, Sewage, Warm Water, Chilled Water, Hot Water, Glycol mixtures

Body Material

EPDM (Ethylene Propylene Diene Monomer) Rubber

Reinforcement Material

Nylon cord or polyester fabric — multiple plies

Flange Material

Carbon steel (cast iron or ductile iron) — loose or fixed — as specified

Flange Drilling

PN10, PN16, PN25, ANSI Class 150, GB/T — as specified

Arch Type

Single arch (standard); Multiple arch (optional for greater movement)

End Connections

Flanged (integral loose flanges or fixed flanges) — as specified

Movement Capabilities

— Axial Compression

15–25 mm (depending on size and pressure rating)

— Axial Extension

10–20 mm (depending on size)

— Lateral Deflection

15–30 mm (depending on size)

— Angular Rotation

15°–35° (depending on size)

Testing Standards

GB/T26121 / ISO 5208

Hydrostatic Test Pressure

1.5 × rated pressure

Vacuum Test

-0.1 MPa (vacuum rating, no collapse)

Temperature Range (EPDM)

-40°C to +120°C

Applicable Media

Hot water (up to 120°C), chilled water (down to -40°C with glycol), sewage, tap water, dilute acids/alkalis, water-glycol mixtures

Optional Features

Limit / Control rods (axial extension protection), Multiple arch design, Threaded ends (small diameters), Neoprene, NBR, or Viton rubber options

Coating (Flanges)

Epoxy or anti-rust paint — as specified

Installation Guideline

Reason

Install as close as possible to the vibration source (pump, chiller)

Maximizes vibration isolation effectiveness — the joint must decouple the equipment from rigid piping.

Do not use rubber joints to correct gross pipe misalignment

Designed for minor misalignment only (15–35° angular, 15–30 mm lateral). Large misalignment requires pipe re-routing.

Install with limit / control rods for systems with high axial pressure thrust

Control rods limit axial extension while still allowing vibration absorption — prevents over-extension damage from pressure end loads.

Support piping near the rubber joint

Piping must be independently supported — rubber joint should not carry pipe weight.

Do not install in tension (stretched) or compression (pre-loaded) during installation

Install in relaxed, neutral position — allows equal movement in both directions.

For outdoor installation, consider weather cover or UV-resistant rubber

EPDM has good UV resistance, but long-term direct sunlight exposure may accelerate aging.

For hot water systems (90–120°C), ensure temperature is within EPDM rating

Standard EPDM is rated to 120°C — do not exceed.

For systems with glycol, verify compatibility with EPDM

EPDM is compatible with most ethylene and propylene glycol mixtures up to 50%.

For vacuum service, specify vacuum-rated design

Standard rubber joint may collapse under full vacuum — specify reinforced design.

Equipment

Connection

Rubber Joint Sizes

Purpose

Chilled Water Pump

Suction & Discharge

DN50–DN300

Vibration isolation, thermal expansion

Hot Water Pump

Suction & Discharge

DN50–DN300

Vibration isolation, thermal expansion

Centrifugal Chiller

Evaporator & Condenser nozzles

DN100–DN600

Equipment vibration isolation, thermal movement

Air Handling Unit (AHU)

Coil connections

DN50–DN200

Isolate fan vibration, coil movement

Cooling Tower

Basin connections

DN100–DN500

Thermal expansion, pump vibration

Heat Exchanger

Shell & tube nozzles

DN80–DN400

Thermal expansion, pressure surge protection

Expansion Tank

Tank connection

DN25–DN80

Thermal movement isolation

Consideration

Rubber Joint

Metal Bellows Expansion Joint

Vibration absorption

Excellent

Poor (transmits vibration)

Noise reduction

Excellent

Poor

Movement capability

Good (axial, lateral, angular)

Excellent

Pressure rating

Up to 2.5 MPa (25 bar)

Up to 10+ MPa

Temperature range

-40°C to +120°C

-200°C to +800°C

Cost (DN100–DN600)

Low – Moderate

High – Very high

HVAC application suitability

Excellent

Overkill / expensive