Lianyi PHE Gaskets are manufactured from different rubber compound that have been specially developed by Lianyi's national leveled senior experts according to the different applications and environments of various Industries that utilize PHE in their unique production cycles.
There are more than12 full developed available polymers are used for making PHE gaskets that with more than 200 different models, the gasket single plate heat transfer area ranged from 0.01 to 4 Sqm. Special request polymer type and performance gasket can be also worked out according to your practical application environment of the industry production and the chemical profile of the product and medium being heated or cooled.
In accordance with assembling form PHE gaskets fall into two large categories, the Glued Fastening Type and Glue Free Fastening Type.

Glued Fastening Type Gasket:

Glued fastening type gaskets are preferred :
● on large plates
● when units are opened frequently
● on high pressure duties
● when the gasket will be swelling due to chemical attack

Glued fastening type gasket has a simple structure but contrast with glue free fastening type it is inconvenient to remove and clean for regasketing.

The four factors creating a perfect glue bond:
●Clean plate groove
●Clean gasket
●Compression
●Glue curing

Glue Free Fastening Type Gasket:

1. Clip-on

It is a glue-free gasket system the gasket is attached to the plate by two gasket prongs which slip under the edge of the plate to hold the gasket securely in alignment in the gasket groove. The prongs are situated at regular intervals around the periphery of the plate. The gasket structure is slightly more complicated than a glue fastening type gasket but it is easy to remove and re-gasket.

2. Snap-on

There are strong rubber buttons along the gasket edge, press the buttons into the relevant holes in the plate, then the gasket is snapped on. The gasket structure is slightly more complicated than a glue fastening type but it is easy to remove and re-gasket.

Incompressibility
The rubber compound can change shape, so that after being squeezed it will return to its original vulcanized shape.

Strength
It is strong enough to withstand the forces normally incurred by squeezing into position and being acted upon by pressurized liquid.

Softness
This is adjusted by compounding so that the rubber is strong enough for the application but still soft enough to conform closely to the metal surfaces and provides a seal without undue stresses being applied.

Resistance to Fluid
The high molecular weigh, cross linked polymer matrix is resistant to penetration by any fluid of a dissimilar chemical nature to itself.

Resistance to Temperature
All polymers will only behave as a rubber over a relatively short range of temperature. Thus careful selection of the compound according to the required temperature range is vital.

Longevity
Synthetic polymers have a built in superiority in terms of useful lifetime, and modern additives can further enhance this property. It is in this area that the correct compound selection is of vital importance.

package : 540 X 355 X 325 mm;
　　　　　1100 X 800 X 740mm

Of all the component part materials, rubber is the least understood. Unlike metals and plastics, rubber does not have universal cut-and-dried design criteria. Choosing the right rubber material gasket for your PHE application can be a nightmare.

● The choice of rubber materials depends on
- Fluids – chemical attack or not
-The combination of temperature and pressure

● The choice of rubber materials depends on
- Fluids – chemical attack or not
-The combination of temperature and pressure

● Nitrile (NBR)
- Standard material up to 130℃
- NBR HT (performance) up to 140℃
- NBR B (base) for lower temperature
Application related NBR qualities
- NBR (FDA food grade) - All the ingredients and amounts in the compound formula are accepted by the FDA and do meet the requirements of FDA list of Substances and Limitations.
- NBR LT - for low temperature in refrigeration applications
- HNBR (hydrogenated) for duties where normal NBR swells and for higher termperatures

● EPDM
- Standard material up to 160℃
- Standard EPDM qualities
- EPDM for glued gaskets (crushing resistant)
- EPDMC for clip-on gaskets at high temperature
- EPDMCT as above but for thing gaskets in models with low pressing depth (1.5 – 3 mm)
Application related EPDM qualities
- EPDM (FDA food grade) –All the ingredients and amounts in the compound formula are accepted by the FDA and do meet the requirements of FDA list of Substances and Limitations.

- EPDM AL for increased pressure resistance in certain chemical duties where normal EPDM swells

Gasket - composition in General
Rubber materials are blends of additives.
Each rubber material is unique. The most important ingredient is the POLYMER, which usually around 50% by weight of the rubber material.
A typical compound formulation may look like:

All additives (type and concentration) effect the properties of the rubber material, thus influencing the final properties of the gasket.

Lianyi Rubber Materials
A rubber material developed for a certain product is seldom useful in other applications. For Lianyi's high performance products there are always specially developed materials to fulfill the specific demand. The synthetic polymers are manufactured to achieve special properties that Natural Rubber does not have. Examples for such properties are resistance to oils and special chemicals, high temperature and weather (ozone, UV-light).

Chemical Resistance
Each rubber material has its unique resistance towards various chemicals. Polymer used, as well as additives, effect which chemicals each rubber material is suitable for. LIANYI compounds rubber materials are fully developed for optimum performance.

High Temperature
At high temperatures the rubber will be attacked faster by the chemicals in use, and the surrounding oxygen. The oxidation process will either make the rubber harder (the most common one) OR make it softer (less common), OR both at the same time. Either way the change in properties will reduce the performance. All rubber materials have a maximum continuous temperature, which should not be exceeded to maintain good performance and to achieve a reasonable lifetime.

Low Temperature
At low temperatures the stiffness increases, and the elasticity decreases. This influences the sealing force of the gaskets. All rubber materials have a certain lowest temperature that have to be exceeded to be able to perform well enough as a gasket.

Food Applications
For food applications there are demands according to international standards. The usual one for PHE gaskets is FDA (USA). This standard regulates what additives are allowed to be used in the rubber and to what content. It also sets demands on what tests have to be done to ensure the quality level.

Typical Rubber Polymer for PHE Gasket
The typical standard materials for PHE gaskets are EPDM and Nitrile rubber (NBR). EPDM is used normally for non-fatty/oily applications, and NBR for oil/fat applications. But there are no rules without exceptions. An "oil", and fatty application may have a low fat content, making the application more suitable for EPDM instead of NBR.
Other rubbers used for PHEs are Hydrogenated Nitrile Rubber (HNBR), Fluorocarbon rubber (FKM), Butyl, Neoprene Rubber, Epichloro Hydrin Rubber, High Temp EPDM, High Temp Nitrile, but Natural Rubber (NR) and Silicone Rubber (Q) are less common ones.

Here, we would like especially to present Lianyi High Temperature Nitrile to you. This is a new type of polymer specially developed by Lianyi for high temperature but with a lower production cost than HNBR. This polymer is developed upon the basis of ordinary NBR, but the work temperature range reaches -20℃～140℃.It has an excellent resistance to non-polar or weak polar oil, such as gasoline, fatty group oil, vegetable oil and so on.
Lianyi's experts offer unsurpassed compound capability and can also work out suitable gasket polymers according to your request or the application environment of your production. Lianyi company laboratory is charged with the responsibility of testing each batch of compound for accurate properties prior manufacturing.