Double Sphere Rubber Expansion Joint

Two arches in one rubber body. Takes more axial extension and angular movement than a single sphere joint of the same size. DN32–DN1000.

Size Range: DN32–DN1000 (1¼"–40")
Length: 165–340 mm
Movement: Up to 25 mm extension, 25° angular
Pressure:PN10 / PN16 / PN25
Rubber:EPDM / NBR / NR / CR / IIR
Flange:Carbon steel, SS304, SS316L

Single Sphere Rubber Expansion Joint Dimensions

DN32 to DN1000. All dimensions in mm. Flange drilling to the standard you choose — see Flanges below.

Swipe the table →

DN	Inch	Length L	Axial movement		Lateral	Angular
DN	Inch	Length L	Extension	Compression	Lateral	Angular
32	1¼"	165	25	20	10	25°
40	1½"	165	25	20	10	25°
50	2"	165	25	20	10	25°
65	2½"	175	25	20	10	25°
80	3"	175	25	20	10	25°
100	4"	225	25	20	15	25°
125	5"	225	25	20	15	25°
150	6"	225	25	20	15	25°
200	8"	325	25	20	20	25°
250	10"	325	25	20	20	25°
300	12"	325	25	20	20	25°
350	14"	330	25	20	20	25°
400	16"	330	25	20	20	25°
450	18"	330	25	20	20	25°
500	20"	340	25	20	20	25°
600	24"	240	25	20	20	25°
700	28"	260	25	20	20	25°
800	32"	260	25	20	20	25°
900	36"	280	25	20	20	25°
1000	40"	280	25	20	20	25°

Face-to-face length can be changed to fit an existing gap.

Single Sphere or Double Sphere?

Same flanges, same bore. The double sphere body is longer and moves further — this is the difference, size by size.

Single sphereDouble sphere

DN50 (2")

Length L

105 mm

165 mm

Axial extension

7 mm

25 mm

Axial compression

10 mm

20 mm

Lateral

10 mm

Angular

15 °

25 °

DN100 (4")

Length L

150 mm

225 mm

Axial extension

10 mm

25 mm

Axial compression

19 mm

20 mm

Lateral

13 mm

15 mm

Angular

15 °

25 °

DN150 (6")

Length L

180 mm

225 mm

Axial extension

12 mm

25 mm

Axial compression

20 mm

Lateral

14 mm

15 mm

Angular

15 °

25 °

Choose double sphere when

Stay with single sphere when

How It’s Built

Five parts, each one you can specify.

Outer rubber: — IIR, CR, EPDM, NR or NBR.
Inner rubber: — Chosen for your medium.
Polyester cord fabric: — Runs through both arches in one piece.
Flange : — Q235 carbon steel, SS304 or SS316L.
Steel wire ring : — Locks each end of the body into its flange.

Choose the Rubber by Medium and Temperature

The rubber decides what the joint can carry. Pick it by the hottest temperature in your line, then check the medium below.

Service temperature

Joint rating, continuous Compound limit, short periods only

NRNatural rubber

Joint rating, continuous: −30 to +70 °C . Compound limit, short periods only: −50 to +100 °C.

NBRNitrile

Joint rating, continuous: −20 to +80 °C . Compound limit, short periods only: −30 to +120 °C.

CRNeoprene

Joint rating, continuous: −20 to +100 °C . Compound limit, short periods only: −40 to +120 °C.

IIRButyl

Joint rating, continuous: −30 to +110 °C . Compound limit, short periods only: −40 to +140 °C.

EPDMEPDM

Joint rating, continuous: −30 to +120 °C . Compound limit, short periods only: −50 to +150 °C.

CSMHypalon®-type CSM

Joint rating, continuous: −20 to +110 °C . Compound limit, short periods only: −30 to +140 °C.

FKMViton®-type FKM

Joint rating, continuous: −15 to +150 °C . Compound limit, short periods only: −20 to +220 °C.

PTFEPTFE lined

Joint rating, continuous: −20 to +120 °C . Compound limit, short periods only: −40 to +200 °C.

Dark bars: continuous rating of the finished joint. Light bars: limit of the compound itself, short periods only.

How the compounds compare

Property	NR	NBR	CR	IIR	EPDM	CSM	FKM
Best for	Cold water, abrasive slurry	Oil, fuel, oily water	Seawater, outdoor lines	Acids, gas, vacuum	Water, hot water, outdoor	Oxidising chemicals, outdoor	Hot oil, solvents, strong acids
Mechanical
Tensile strength	Excellent	Good	Good	Fair	Good	Good	Good
Tear resistance	Excellent	Good	Good	Good	Fair	Good	Fair
Abrasion resistance	Excellent	Good	Good	Fair	Good	Good	Good
Flex life (movement)	Excellent	Good	Good	Good	Good	Good	Fair
Environment
Heat ageing	Fair	Good	Good	Excellent	Excellent	Excellent	Excellent
Ozone and sunlight	Poor	Poor	Good	Excellent	Excellent	Excellent	Excellent
Gas tightness / vacuum	Good	Good	Good	Excellent	Good	Good	Excellent
Water and hot water	Good	Good	Good	Excellent	Excellent	Good	Fair
Media
Mineral oil	Poor	Excellent	Good	Poor	Poor	Good	Excellent
Fuel, gasoline	Poor	Good	Fair	Poor	Poor	Fair	Excellent
Aromatics (benzene)	Poor	Poor	Poor	Poor	Poor	Fair	Excellent
Strong acids	Fair	Fair	Good	Good	Good	Good	Excellent
Weak acids	Good	Good	Excellent	Excellent	Excellent	Excellent	Excellent
Strong alkalis	Good	Good	Good	Excellent	Excellent	Excellent	Poor
Weak alkalis	Good	Good	Good	Excellent	Excellent	Excellent	Fair
Relative price	$	$$	$$	$$	$	$$$	$$$$

Can It Handle Your Media?

Pick your type of medium. Ratings are for room temperature — higher temperature or concentration lowers them. Send us the medium, concentration and temperature and we confirm the compound before production.

Search a medium

Medium	NR	NBR	CR	IIR	EPDM	CSM	FKM	PTFE lined	Usually built in
Fresh water, drinking water	A	A	A	A	A	A	A	A	EPDM
Hot water ≤ 100 °C	X	C	B	A	A	B	C	A	EPDM
Seawater, brine	A	A	A	A	A	A	A	A	CR or EPDM
Wastewater, sewage	B	A	A	A	A	A	A	A	EPDM or NBR
Oily water, bilge water	X	A	B	X	C	B	A	A	NBR
Mineral oil, hydraulic oil	X	A	B	X	X	B	A	A	NBR
Diesel, heating oil	X	A	C	X	X	C	A	A	NBR
Gasoline (petrol)	X	B	C	X	X	C	A	A	NBR or FKM
Hot oil above 80 °C	X	C	C	X	X	C	A	A	FKM
Vegetable oil, animal fat	C	A	B	B	C	B	A	A	NBR
Compressed air, oil-free	A	A	A	A	A	A	A	A	EPDM
Compressed air with oil mist	X	A	B	X	C	B	A	A	NBR
Natural gas, LPG	C	A	B	X	X	B	A	A	NBR
Flue gas (SO₂, moist)	C	C	B	A	A	A	A	A	EPDM or IIR
Sulphuric acid ≤ 50 %	B	C	B	A	A	A	A	A	EPDM
Sulphuric acid 50–96 %	X	X	X	C	C	B	A	A	PTFE lined or FKM
Hydrochloric acid ≤ 36 %	C	C	C	B	B	A	A	A	CSM or PTFE lined
Nitric acid ≤ 10 %	X	X	C	B	B	A	A	A	CSM or FKM
Phosphoric acid ≤ 85 %	B	B	B	A	A	A	A	A	EPDM
Acetic acid ≤ 10 %	B	B	B	A	A	B	B	A	EPDM
Caustic soda ≤ 50 %	A	B	A	A	A	A	B	A	EPDM
Ammonia solution	B	B	A	A	A	A	X	A	EPDM
Sodium hypochlorite ≤ 15 %	X	C	C	B	B	A	A	A	CSM or PTFE lined
Salt solutions	A	A	A	A	A	A	A	A	EPDM
Benzene, toluene, xylene	X	X	X	X	X	X	A	A	PTFE lined or FKM
Acetone, MEK	C	X	X	A	A	C	X	A	EPDM
Alcohols (ethanol, methanol)	A	B	A	A	A	A	C	A	EPDM
Ethylene glycol, antifreeze	A	A	A	A	A	A	A	A	EPDM
Abrasive slurry (sand, tailings)	A	B	B	C	B	B	C	C	NR
Lime and cement slurry	A	A	A	A	A	A	A	A	NR or EPDM
FGD slurry (gypsum, chlorides)	B	C	B	A	A	A	A	B	EPDM or IIR
No medium matches your search. Tell us the medium, concentration and temperature and we’ll check it for you.

ALittle or no effect BMinor effect, suitable CLimited — ask us first XNot suitable

Pressure, Temperature and Vacuum

Choose the class by working pressure. Vacuum is the most a joint of that class takes on a pump suction line.

Pressure classes

Class	Working pressure	Burst pressure	Vacuum
PN10	1.0 MPa	2.0 MPa	53.3 kPa (400 mmHg)
PN16	1.6 MPa	3.0 MPa	86.7 kPa (650 mmHg)
PN25	2.5 MPa	4.5 MPa	100 kPa (750 mmHg)

Temperature

−15 to +100 °C standard. −30 to +150 °C with a special compound.

Higher vacuum

Above the listed vacuum, order the joint with a vacuum support ring.

Rating by size

Size	Extension	Lateral	Angular
DN32 – DN80	25 mm	10 mm	25°
DN100 – DN150	25 mm	15 mm	25°
DN200 – DN1000	25 mm	20 mm	25°

For DN600 and above, confirm the pressure class with us before ordering.

Flange Standards and Materials

Pick your pipe’s flange standard, class and size. If the numbers match your flange, our joint bolts straight on — no adapter, no re-drilling.

Check your flange

Standard Class Size

Flange OD — D

Bolt circle — K

Bolt holes — n × d

Bolt size

Flange thickness — t*

Standards we drill to

EN 1092-1

PN6 · PN10 · PN16 · PN25 · PN40 — same drilling as DIN, BS 4504, GB/T 9119
ASME B16.5 / B16.47

Class 150 · Class 300 · Series A 26"–60"; AWWA C207 Class D
JIS B2220

5K · 10K · 16K · 20K
AS 2129 / AS 4087

Table D · Table E · PN16
Your drawing

GOST, BS 10 or any special drilling; tapped holes on request

Flange drilling chart

EN · ASME · JIS · AS — OD, bolt circle, holes, thickness

Flange material and finish

Installing a Double Sphere Joint

Four rules that prevent most failures

Anchor the pipe on both sides

The longer body stretches further under pressure. Anchors, not the joint, should hold the pipe.

Use control rods at pumps

Rods take the pressure thrust when a pump or valve cannot.

Install at the listed length

Do not stretch or squeeze the joint to fill a wrong gap.

Keep paint and insulation off the rubber

Solvents and trapped heat shorten rubber life.

Options

Add these when the job needs them — each one is priced separately.

Control rods

Stop over-extension under pressure thrust. Fit them at pump outlets or where the pipe is not anchored.

Vacuum support ring

A steel ring inside the arch keeps it from collapsing on suction lines.

PTFE lining

White PTFE liner for strong acids, solvents and food-grade media.

Tapped holes & custom drilling

Threaded bolt holes for wafer valves, or drilling to your drawing.

Why Buy From Our Factory

A rubber joint is a simple product. What decides whether it lasts is the right material for your working conditions — and then the price.

Working conditions confirmed first

Size, pressure, medium, temperature, length and flange drilling are checked against your data and sent back on a drawing before production starts.

Full material, nothing thinned

Flanges and unions to full thickness, cord plies matched to the pressure class, rubber compounded in-house for your medium.

Pressure tested before packing

Every joint is tested at 1.5 × working pressure and checked for leaks and bulging.

Factory price, quoted the same day

You buy from the production line, not through a trader. Send size, pressure and medium and get a price the same working day.

Where It’s Installed

Pump suction and discharge

Stops pump vibration and noise travelling down the line. Add a vacuum ring on the suction side.

HVAC chillers and cooling towers

Takes thermal movement and isolates vibration at chillers, cooling towers and AHUs.

Water treatment and pump stations

Compensates settlement and misalignment between pumps, valves and headers.

In Service

Rubber joints from our factory, photographed by customers on site.

Double Sphere Rubber Expansion Joint Price

What you pay depends on a few choices. Send them and we quote the same day.

What changes the price

Size: : DN is the biggest factor
Rubber: : EPDM / NR vs NBR / CR / PTFE lined
Pressure class : PN10 / PN16 / PN25
Flange : Carbon steel vs stainless
Options : Control rods, vacuum rings
Quantity : Price breaks at 200 pcs

Reference price

Size	Price per piece
DN50	Contact Us
DN100	Contact Us
DN150	Contact Us
DN200	Contact Us
DN300	Contact Us

EPDM, PN16, galvanised carbon steel flanges, EXW Gongyi / FOB Tianjin or Ningbo or Guangzhou. Prices change with steel and rubber costs.

Downloads

Datasheets, drawings and references for submittals.

Control rods

Single sphere datasheet

Dimensions DN32–DN1000, pressure classes, materials

2D drawing

2D drawing Half-section, opens in AutoCAD

For all our rubber joints

Flange drilling chart

EN, ASME, JIS, AS — holes, bolt circle, thickness

Rubber selection and chemical resistance chart

8 compounds, 40 media, temperature limits

Installation guide

Anchors, control rods, bolting sequence

EPDM body submittal

Water, hot water, outdoor lines

NBR body submittal

Oil, fuel and oily water

Frequently Asked Questions

What is the difference between single and double sphere joints?

The double sphere has two arches and a longer body. At the same size it takes more axial extension and angular movement — compare them size by size above.

Is a double sphere joint the same as a twin sphere joint?

Yes. Double sphere, twin sphere and double arch all describe the same two-arch design.

How long is a DN100 double sphere joint?

225 mm face-to-face. Other sizes are in the table; we can also make a length to fit your gap.

Do double sphere joints need control rods?

More often than single sphere joints, because the longer body stretches further under pressure. Fit them at pumps and on unanchored lines.

Which rubber should I use for oil?

NBR. For oil outdoors we can add a CR outer cover for ozone resistance.

What is the MOQ and lead time?

MOQ 1 pcs. Common sizes in EPDM and NBR are usually in stock and ship in 3-7 days; other sizes take 10-20 days.