Diaphragms type AS

Diaphragms Materials of the non-return valves

Different media and operating conditions require different diaphragm materials to ensure reliable and long-lasting function.

Selection criteria

Medium	Wie korrosiv ist Verstehen Sie die Korrosivität des Mediums, um zu bestimmen, welches Material für die Membran gewählt werden sollte.
Temperatur	Stellen Sie sicher, dass das Material der Membran die minimalen und maximalen Temperaturen der Anwendung aushalten kann.
Fliessgeschwindigkeit	Fluide 2.5m/sec sollte nicht überschritten werden
Max. Betriebsdruck	16bar (Höhere Drücke könnten getestet werden.)
Zertifizierung	FDA Trinkwasser

Elastomer		Temp. min °C	Temp. Constant °C	Temp. max °C	Temp. Max. °C Hot air
Natural rubber	NR / PGR	-45°C	+70°C	+70°C	+80°C
Ethylene propylene diene rubber	EPDM	-55°C	+150°C	+210°C	+210°C
Silicone rubber	MVQ	-55°C	+180°C	+230°C	+210°C
Fluorosilicone rubber	MFQ/FVMQ	-55°C	+180°C	+230°C	+180°C
Elastosil	HCR	-50°C	+180°C	+225°C	+160°C
Nitrile rubber	NBR	-25°C	+80°C	+100°C	+80°C
Fluororubber	FPM (Viton)	-40°C	+200°C	+230°C	--

Natural rubber

Resistance to chemicals

+ Very good elasticity and mechanical properties (tensile strength, elongation at break, abrasion resistance) + Low permanent deformation after stress, high flexural fatigue strength

less / not resistant to

- moderate to poor resistance to oil, heat, weathering and ozone
- flammable

Examples of areas of application

Agriculture
Fish farming
Water supply
Pumping stations
Irrigation systems
Breweries
Sugar industry
Food industry (restricted)
Washing machines
Dairies

Ethylene propylene diene rubber

Resistance to chemicals

+ with drinking water certificate
+ suitable for sterilizing food for a short time under steam
+ excellent resistance to weathering, ageing, ozone, chemicals, hot water, steam and polar solvents such as acetone, methanol or esters; excellent electrical insulation properties
+ Very good heat resistance, good behavior at low temperatures
+ Resistant to animal and vegetable fats

less / not resistant to

- Low resistance to aliphatic and aromatic hydrocarbons (mineral oils, petrol)
- Flammable

Examples of areas of application

Drinking water
Domestic installations
Hot water/boilers
Solar technology
Waste water systems
Air conditioning systems
Biogas
Waterworks
Pipework construction
Ventilation valves
Data center security
Water supply Water supply
Pipeline construction
Ventilation valves
Data center security
Heat pumps
Geothermal energy
Washing machines

Silicone rubber

Resistance to chemicals

+ with drinking water certificate (for cold and hot water)
+ physiologically flawless
+ very high resistance to heat and cold; excellent resistance to weathering, ageing and ozone
+ Good electrical insulation properties; the mechanical values remain constant over a wide temperature range

less / not resistant to

- medium mechanical properties; medium oil resistance; sensitive to hot water and steam
- Poor fuel resistance

Examples of areas of application

Medical technology
Pharmaceutical industry
Cosmetics
Food industry
Biotechnology
Biopharma
Air conditioning
Textile industry
Data center security
Dairy

Fluorosilicone rubber

Resistance to chemicals

+ very high resistance to heat and cold; excellent resistance to weathering, ageing and ozone
+ good electrical insulation properties; the mechanical values remain constant over a wide temperature range
+ Good oil and fuel resistance
+ Higher tensile strength and tear resistance than silicone

less / not resistant to

- Lower elasticity than silicone
- Slightly poorer low-temperature properties than silicone

Examples of areas of application

Aviation refueling
Oil & gas
Defense industry
Rail transport
Military industry
Security and defense technology
Compressors
Marine
Onshore & offshore

Elastosil

Resistance to chemicals

+ Polar liquids such as short-chain alcohols and low-molecular ketones hardly cause any swelling + Resistance to aqueous solutions of weak acids, alkalis and salts + High steam resistance 160°C continuous load for 2 months

less / not resistant to

- Limited oil and fuel resistance
- Limited resistance to concentrated acids and oxidizing substances

Examples of areas of application

Medical technology
Biotechnology
Pharmaceutical industry
Food industry
Cosmetics
Water without certification
Data center security

Nitrile rubber

Resistance to chemicals

+ Very good oil and petrol resistance and more favorable than FPM (Viton) + Equally strong resistance to chemical compounds such as silicone, propane, butane, alcohol, acids and bases + Good mechanical strength; low permanent deformation under pressure, flexible at low temperatures + Better heat resistance than SBR, low gas permeability

less / not resistant to

- moderate weather resistance; flammable with toxic fumes
- poor resistance to aromatics and polar solvents
- low resistance to ozone, weathering and ageing

Examples of areas of application

Oil & gas
Heating systems
Pneumatics
Compressed air systems
Pump construction
Compressors
Petrochemicals
Defense industry
Firefighting
Chemical industry
Washing plants
Mining

Fluororubber

Resistance to chemicals

+ very high heat resistance; excellent resistance to weathering, ageing and ozone
+ excellent recovery properties after deformation
+ very good chemical resistance; low gas permeability
+ resistant to hydrocarbonates, ozone, many acids, animal and vegetable oils
+ fuel resistant
+ does not burn in its own flame

less / not resistant to

- sensitive to the effects of hot water, steam, amines, organic acids and polar solvents
- poor low-temperature flexibility

Examples of areas of application

Petrochemicals
Nuclear industry
Chemical industry
Process engineering
Power plants
Oil & Gas
Seawater desalination
Onshore & offshore
Marine
Pharmaceutical industry
Aircraft refueling
Marine industry
Geothermal energy

In many applications, the pressure conditions must be adjusted at elevated temperatures, as materials can change their mechanical properties when exposed to heat.

Pressure loss curve

With the improved cone generation introduced in 2024, the AS valves have a cross-section that is up to 20% larger thanks to the new hole pattern. As a result, the new generation can further reduce the pressure loss.