Single-Sphere Rubber Expansion Joints

A single-sphere rubber expansion joint is a non-metallic flexible connector featuring a single long radius arch to absorb various types of movements in piping systems, including axial, lateral, and angular deflections.

Construction Details

The single-sphere rubber expansion joint has a molded spherical rubber body, the middle of which resembles a round ball (single sphere). The joint body consists of the inner tube, the carcass made of woven fabric plies or tie cord impregnated with rubber and reinforced by steel wire, and a rubber cover, which are together brought up from the joint body to from a seal bead. Two floating metallic flanges with proper grooves are furnished to accommodate the seal bead at the ends of the joint. The metallic flanges shall be drilled in accordance with the customer order as required, to match the mating flanges in piping systems.

Advantages & Applications

In single-sphere rubber expansion joints, the long-radius contour of the molded spherical body prevents sediment accumulation and creates less turbulence and pressure drop than spool-arch joints. The seal bead at each joint end eliminates any requirement for gaskets between mating flanges. The seal bead is partially recessed into the floating flange when installed, providing a robust and resilient sealing system for the lift of the joint.

Single-sphere rubber expansion joints are used across various industries, including: (1) Water and Wastewater Treatment: To manage system vibrations and movements in fluid transport pipes. (2) HVAC Systems: In air conditioning and heating systems to compensate for thermal expansion and minimize noise transmission. (3) Pumping Systems: Near pumps and compressors to absorb vibrations and protect the integrity of the piping. (4) Chemical and Power Plants: To manage thermal expansion and mechanical stress in process piping.

Dimensions & Technical Parameters

NPS	L mm	P psi	V mm Hg
1	95	16	660
1 1/4	95	16	660
1 1/2	95	16	660
2	105	16	660
2 1/2	115	16	660
3	130	16	660
4	135	16	660
5	170	16	660
6	180	16	660
8	205	16	660
10	240	10	660
12	260	10	660
14	265	10	660
16	265	7	660
18	265	7	660
20	265	7	660
24	265	7	660
28	265	7	660
32	265	7	660
36	265	7	660
40	265	7	660
48	265	7	660

*Series HM-SP-10A of single-sphere rubber expansion joint: neutral length (L), maximum pressure (P), vacuum pressure (V).

NPS	Ac mm	Ae mm	Lt mm	Agu
1	6	8	8	15°
1 1/4	8	4	8	15°
1 1/2	8	4	8	15°
2	8	5	8	15°
2 1/2	12	6	10	15°
3	12	6	10	15°
4	18	10	12	15°
5	18	10	12	15°
6	18	10	12	15°
8	25	14	22	15°
10	25	14	22	15°
12	25	14	22	15°
14	25	16	22	15°
16	25	16	22	15°
18	25	16	22	15°
20	25	16	22	15°
24	25	16	22	15°
28	25	16	22	15°
32	25	16	22	12°
36	25	16	22	10°
40	25	16	22	10°
48	25	16	22	8°

*Series HM-SP-10A of single-sphere rubber expansion joint: maximum allowable movement of axial compression (Ac), axial extension (Ae), lateral deflection (Lt), and angular direction (Agu).

NPS	L inch	P psi	V mm Hg
1	6	225	26
1 1/4	6	225	26
1 1/2	6	225	26
2	6	225	26
2 1/2	6	225	26
3	6	225	26
4	6	225	26
5	6	225	26
6	6	225	26
8	6	225	26
10	8	150	26
12	8	150	26
14	8	150	26
16	8	150	26
18	8	150	26
20	8	150	26
24	8	150	26

*Series HM-SP-10B of single-sphere rubber expansion joint: neutral length (L), maximum pressure (P), vacuum pressure (V).

NPS	Ac	Ae	Lt	Agu
1	1/2"	3/8"	1/2"	15°
1 1/4	1/2"	3/8"	1/2"	15°
1 1/2	1/2"	3/8"	1/2"	15°
2	1/2"	3/8"	1/2"	15°
2 1/2	1/2"	3/8"	1/2"	15°
3	1/2"	3/8"	1/2"	15°
4	5/8"	3/8"	1/2"	15°
5	5/8"	3/8"	1/2"	15°
6	5/8"	3/8"	1/2"	15°
8	5/8"	3/8"	1/2"	15°
10	3/4"	1/2"	3/4"	15°
12	3/4"	1/2"	3/4"	15°
14	3/4"	1/2"	3/4"	15°
16	3/4"	1/2"	3/4"	15°
18	3/4"	1/2"	3/4"	15°
20	3/4"	1/2"	3/4"	15°
24	3/4"	1/2"	3/4"	15°

*Series HM-SP-10B of single-sphere rubber expansion joint: maximum allowable movement of axial compression (Ac), axial extension (Ae), lateral deflection (Lt), and angular direction (Agu).

Material Selection

• Both the rubber tube and cover of the rubber expansion joint shall be made from various rubbers such as natural rubber, EPDM, Hypalon (CSM), neoprene (CR), Buna N (NBR), Viton (FKM), EPDM+PTFE.
• The carcass (supporting canvas) shall be made from nylon or polyester woven fabric or tire cord, impregnated with rubber and reinforced by carbon steel or stainless steel rings.
• The floating flanges are usually made from carbon steel (ASTM A105, S235JR) or stainless steel (SS304/304L, SS316/316L) in accordance with a series of international standards.

Specification of Rubber Expansion Joints
Single Sphere	Twin Sphere	Union Spherical
Spool Arch	Tie Rods	Special Design
Flange Drilling	Installation & Maintenance	Testing & Inspection

*Click to view the technical specification of various types of rubber expansion joints.