Product Description
A rubber expansion joint with a built-in negative pressure ring is a type of flexible
connector used in piping systems to compensate for thermal expansion, vibrations,
and slight misalignments. The negative pressure ring (also called a vacuum support
ring or anti-collapse ring) is an internal structural component designed to prevent the
rubber joint from collapsing inward when exposed to negative pressure or vacuum
conditions.
Installation technical parameters
NO | Name | Material |
1 | Outer/inner rubber | NR, EPDM, NBR, Neoprene etc. |
2 | Frame | Nylon cord fabric |
3 | Pressurized ring | Steel wire strand |
4 | Flange | Carbon steel galvanized, paint ductile iron, stainless steel etc. |
|
Working temperature | -15℃~80℃(-30℃~150℃) |
Working pressure | 6-40bars(PN6-PN40) |
Test pressure | 1.5 times of working pressure |
Explosion pressure | 2 times of working pressure |
Applicable media | Air, water, sewage, sea water, acid, alkali, oil etc.
|


Key Features of Rubber Expansion Joints with Negative Pressure Rings
1. Rubber Body:
• Made from flexible materials like EPDM, NBR, Neoprene, or Viton, depending on the
fluid or gas being transported.
• Absorbs vibrations, reduces noise, and compensates for movements in the piping system.
2. Negative Pressure Ring:
• Usually made of stainless steel, carbon steel, or reinforced plastic.
• Installed inside the rubber joint to provide structural support under vacuum or low-pressure
conditions.
• Prevents the rubber walls from collapsing inward when the system experiences a negative
pressure.
3. Reinforcement Layers:
• The rubber body is reinforced with fabric or metal wire for added strength and durability.
• Works in combination with the negative pressure ring to handle both positive and negative
pressure conditions.
4. Flanged Ends:
• The joint typically has integral flanged ends for easy connection to the piping system.
• The flanges can conform to standards like ASME, DIN, or JIS.

Advantages
1. Prevention of Collapse:
• The negative pressure ring ensures the integrity of the joint under vacuum conditions.
2. Improved Longevity:
• Reduces stress on the rubber body, extending the service life of the expansion joint.
3. Vibration Absorption:
• Maintains the joint’s flexibility and vibration-dampening properties even in vacuum
scenarios.
4. Customizable:
• Available in various sizes, pressure ratings, and materials to suit different applications.

choose the products of ZHICHENG ?
1.24 hours online service-- anytime, anywhere can provide what you want.
2.100% quality inspection before shippment.
3.Strong production capability and strict quality control.

| 1.Inner package: plastic film with carton cases. 2.Outer package: wooden cases(usually the size of 1100mm*1100mm*1100mm). |

Product installation
When the customer installs, we will provide installation instructions, installation
notes and maintenance instructions. and this
is the installation picture of the DN1800 rubber expansion joint.
FAQ
Q: Are you a trading company or a manufacturer?
A: We are manufacturers of rubber expansion joints, metal expansion joints, flexible hoses,
dismantling joints, trimmer joints,flange adapters and flanges with over 30 years experience.
Q: Do you have a catalogue?
A: Yes, we do. Please let me know your email or instant messenger and we will send you our
catalogue.
Q: Can you provide drawings and technical information?
A: Yes, our specialist technical department will design and supply drawings and technical data.
Q: Do you provide samples? Are they free of charge or do you charge for them?
A: Yes, we can provide samples free of charge, but transport costs are borne by the customer.
Q: Can the products be manufactured to the customer's requirements?
A: Yes, the above specifications are standard specifications and we can design and manufacture
as required.
Contact us for more details about price and packing, shipping and
discount now!