Solenoid Valve Guide: Part 4
In the previous parts, we have discussed technical information and other technical aspects related to solenoid valves.
In this part, we are going to discuss the different types of materials used in solenoid valves and their seals.
Seal materials;
NBR (BunaN);
Trade names; Chemigum Hycar (Zeo (Goodyear) Chemical), Ny Syn (copolymer), Paracril (Uniroyal), Krynac (Polysar), PerNitrilen (Mobay).
This is the most widely used O-Ring elastomer.
It has excellent resistance to petroleum products. Excellent compression set, tear and abrasion resistance.
Suitable for Air, Oil, Water, Acetylene, Kerosene, Lime Solutions, Liquefied Petroleum Gases and Turpentine.
- Please note NBR (BunaN) is not recommended for highly aromatic petroleum/gasoline’s or acids.
EPDM (EPR or EPDM) EPDM (EPR)
Excellent resistance to weathering and ozone, water and steam, with good performance in castor and some phosphate ester-based fluids and poor on petroleum/gasoline.
It’s low and high temperature capabilities are good, having excellent resistance to set with good resilience, this low compression set provides a suitable solution for steam sealing. EPDM is suitable for temperatures above the NBR range.
Ethylene-propylene is generally suitable for most photographic solutions as well as numerous chemical solutions. EPDM has served to replace the formerly used butyl.
- Please note EPDM should NEVER be used in contact with mineral based fluids or DI ester based lubricants, due to excessive swell and deterioration. When lubrication is required silicone grease or fluids should be used.
FKM (FPM FLUOROELASTOMER)
It has high temperature capabilities, excellent resistance to hydraulic oils, petrol and many other chemicals.
FKM O-Rings are used in automobile and other mechanical devices requiring maximum resistance to elevated temperature and to many functional fluids.
FKM is a fluorocarbon elastomer.
Primarily developed for handling hydrocarbons such as jet fuels, gasoline’s, solvent, etc., which normally caused detrimental swelling to NBR. FKM has a high temperature range similar to ethylene propylene but is more resistant to “dry heat”.
FKM has a rather wide range of chemical capability.
*PTFE / Teflon*
PTFE is a fluorocarbon resin known as a disc sealing material solution where all other synthetic materials have failed. Rulon is a form of Teflon having fillers which have been added for improved mechanical properties.
Teflon with fillers are considered more of a plastic than a resilient-type material.
They are virtually unattacked by any fluid.
PTFE provides sealing solutions for cryogenic and steam applications.
*Teflon is a registered trademark of Du-Pont. It must be noted that PTFE sealing will allow slight let-by.
Silicone;
This elastomer provides high and low temperature solutions under certain conditions for numerous applications (it must be noted that silicone is not suitable for steam applications).
It can handle hydrogen peroxide and some acid solutions.
Silicone’s retention of properties at high temperatures is superior to other elastic materials.
It must be noted that Silicone has poor tensile strength, tear resistance and abrasion resistance.
Neoprene;
Neoprene is commonly used for refrigeration systems sealing as an external seal. Suitable for alcohol, mild acids, water, air, ammonia, argon gas and other gases.
Sigodur (filled PTFE) & Ruby;
Stiff materials particularly suitable for heavy duty applications.
KALREZ Spectrum 6345;
KALREZ Spectrum 6375 is a compound specifically designed for the chemical process industry. This compound has excellent broad chemical resistance, good mechanical properties, and outstanding hot-air ageing properties.
KALREZ6375 is well suited for use in mixed process streams because of its excellent resistance to acids, bases and amines.
It is also recommended for use in hot water, steam, pure ethylene oxide and propylene oxide.
Metals;
Ag (silver)
Silver is a soft, malleable metal with a characteristic sheen.
It has the highest thermal and electrical conductivity of all metals.
Al (aluminium)
Derived from the Latin ALUMEN for ALUM (Potassium aluminium sulphate).
A lightweight material that offers high strength and rigidity along with good corrosion resistance and heat dissipation.
Cu (Copper)
Copper is an important engineering material since it is widely used in its pure state and also in alloys with other metals. In its pure state, it is the most important material in the electrical industry.
It has high electrical conductivity and corrosion resistance and is easy to fabricate.
It has reasonable tensile strength, controllable annealing properties and general soldering and joining characteristics.
Cu Sn (bronze)
Bronze alloys consist of copper and tin primarily and these can be known as “tin bronzes”. Since phosphorus is usually added to these alloys as a deoxidising agent during casting, the tin bronzes are commercially known as “phosphor bronzes”.
These alloys possess desirable properties such as high strength, wear resistance, and good sea water resistance.
Cu Zu (brass)
Brass is probably the best known of the “yellow metals” and it is produced in a wide variety of forms with many different characteristics and attributes.
It is a basic alloy of copper and zinc and it finds many engineering applications.
Fe CrNi 300 Series Stainless Steel (18-8) Austenitic
303 Stainless Steel is essentially low-carbon steel to which chromium has been added. It is the addition of chromium, in amounts of 18%, that adds strength and gives stainless steel its unique ‘stainless’, corrosion-resisting properties.
The corrosion resistance, as well as other useful properties of the steel, is enhanced by the addition of other elements such as 8% nickel.
316 Stainless Steel;
316 Stainless Steel is essentially low-carbon steel to which chromium has been added.
It is the addition of chromium, in amounts of 18%, that adds strength and gives stainless steel its unique ‘stainless’, corrosion resistance, as well as other useful properties of the steel, is enhanced by the addition of other elements such as 12% nickel.
430F & 430FR Magnetic Stainless Steel
Type 430F is a solenoid grade stainless steel that has the best magnetic properties and lowest residual magnetism.
Type 430FR stainless, used for corrosive service for many years, also offer improved wear resistance, higher electrical resistivity and increased hardness.
This chart is for general recommendation only.
When looking for valves for corrosive duty applications, details should be provided, particularly media, % concentration, temperature and ambient temperature.
For additional support please contact us on 01234 855888 or email sales@v-flowsolutions.co.uk.
| Valve Body | Seals | Notes | ||||||||
| Material | Alum | Brass | Brz | Cl | Stainless | NBR | EPDM | FKM | PTFE | |
| Acetic Acid 10% | NR | NR | NR | NR | · | NR | · | NR | · | 1 |
| Acetone | · | · | · | · | · | NR | · | NR | · | |
| Acetylene | NR | · | · | NR | · | NR | · | · | · | 1 |
| Air | · | · | · | · | · | · | · | · | · | |
| Ammonia Gas Anhydrous 20% | NR | NR | NR | · | · | NR | · | NR | · | |
| Argon Gas | · | · | · | NR | · | NR | · | · | · | |
| Beer | NR | NR | NR | NR | · | · | · | · | NR | |
| Benzene | · | · | · | NR | · | NR | NR | · | · | |
| Bromine (Liquid) | NR | NR | NR | NR | NR | NR | NR | · | NR | 1 |
| Butane | · | · | · | · | · | · | NR | · | · | |
| Carbon Dioxide (Gas) | · | · | · | · | · | · | · | · | · | |
| Carbon Dioxide (Liquid) | NR | NR | NR | NR | · | NR | NR | NR | · | |
| Carbon Tetrachloride (Dry) | NR | · | · | NR | · | NR | NR | · | · | |
| Carbonated Water | NR | NR | NR | NR | · | · | · | NR | · | |
| Caustic Soda 30% | NR | NR | NR | NR | · | NR | · | NR | · | |
| Chrome Acid 20% - 20C | NR | NR | NR | NR | · | NR | NR | · | · | |
| Chlorine Gas (Dry) | NR | NR | NR | NR | NR | NR | NR | · | · | 1 |
| Chlorine Liquid | NR | NR | NR | NR | NR | NR | NR | 1 | ||
| Chlorine in Water | NR | · | · | NR | · | · | · | NR | · | 2 |
| Coke Oven Gas | · | NR | NR | · | · | · | NR | NR | · | |
| Coolant | NR | · | · | NR | · | · | NR | · | · | |
| Creosote | · | NR | NR | NR | · | NR | NR | · | · | |
| Crude Oil | · | NR | NR | NR | · | · | NR | · | · | |
| De-ionized Water | NR | NR | NR | NR | · | · | · | · | · | |
| De-mineralised Water | NR | NR | NR | NR | · | · | · | · | · | |
| Detergents | NR | · | · | NR | · | · | · | · | · | |
| Diesel Oil | · | · | · | · | · | · | NR | · | · | |
| Distilled Water | NR | · | · | NR | · | · | · | · | · | |
| Ethyl Alcohol | NR | · | · | NR | · | · | · | · | · | |
| Ethylene Glycol | · | · | · | NR | · | · | · | · | · | |
| Ethylene Oxide | NR | NR | NR | NR | · | NR | NR | NR | NR | 1 |
| Food Products | NR | NR | NR | NR | · | · | NR | · | NR | |
| Freon 12 | NR | · | · | · | · | NR | NR | NR | · | |
| Freon 22 | NR | NR | NR | NR | · | NR | NR | NR | · | |
| Freon Solvents | NR | · | · | NR | · | · | NR | NR | · | |
| Fuel Oil | · | · | · | NR | · | NR | NR | · | · | |
| Helium | · | · | · | NR | · | · | · | · | · | |
| Hydraulic Fluids | NR | · | · | NR | · | NR | NR | · | · | |
| Hydrochloric Acid | NR | NR | NR | NR | NR | NR | NR | NR | · | 1 |
| Hydrogen Gas | · | · | · | · | · | · | · | · | · | 3 |
| Hydrogen Sulphide (Dry) | NR | NR | NR | NR | · | NR | · | · | · | |
| Jet Fuel | · | NR | NR | NR | · | · | NR | · | · | |
| Kerosene | · | · | · | · | · | · | NR | · | · | |
| LPG | · | · | · | NR | · | · | NR | · | · | |
| Lubricating Oil | · | · | · | · | · | NR | · | · | · | |
| Methane Gas | · | · | · | · | · | · | NR | · | · | |
| Methyl Alcohol | NR | · | · | · | · | · | · | · | · | |
| Mineral Oil | · | · | · | · | · | · | NR | · | · | |
| Natural Gas | · | · | · | · | · | · | · | · | · | |
| Natural Gas Liquid | NR | · | · | NR | · | NR | NR | NR | · | |
| Nitric Acid 50% 20C | NR | NR | NR | NR | · | NR | NR | · | · | |
| Nitrogen Gas | · | · | · | · | · | · | · | · | · | |
| Nitrogen Liquid | NR | · | · | NR | · | NR | NR | NR | · | 3 |
| Nitrous Oxide | NR | NR | NR | NR | · | NR | · | NR | · | |
| Oxygen Gas | NR | · | · | NR | · | NR | NR | · | · | 3 |
| Oxygen Liquid | · | · | · | NR | · | NR | NR | NR | · | 3 |
| Paraffin | · | · | · | NR | · | · | · | · | · | |
| Perchlcrenthylene 20C | NR | · | · | NR | · | NR | NR | · | · | |
| Phosperic Acid 30% | NR | NR | NR | · | NR | NR | · | · | · | 1 |
| Photographic Solution | NR | NR | NR | NR | NR | NR | NR | NR | 1 | |
| Potable Water | NR | · | · | NR | · | · | · | · | · | |
| Potassium Sulphate | NR | NR | NR | · | · | · | · | · | · | |
| Propane | · | · | · | NR | · | · | NR | · | · | |
| Salt Water | NR | NR | · | NR | · | · | · | · | · | 1 |
| Sea Water | NR | NR | · | NR | · | · | · | · | · | 1 |
| Soapy Water | NR | · | · | NR | · | · | NR | · | · | |
| Sodium Hydroxide 70% | NR | NR | NR | NR | · | NR | · | · | · | |
| Sodium Hypochorite 5% | NR | NR | NR | NR | · | NR | · | · | · | |
| Steam 0 – 50 psi | NR | · | · | NR | · | NR | · | NR | · | |
| Steam 0 – 125 psi | NR | · | · | NR | · | NR | NR | NR | · | |
| Steam Condensate | NR | · | · | NR | · | NR | · | NR | · | |
| Sulphur Dioxide | NR | NR | NR | NR | · | NR | · | NR | · | |
| Sulphuric Acid 40% | NR | NR | NR | NR | NR | · | · | · | · | 1 |
| Sulphurous Acid 5% - 20C | NR | NR | NR | NR | NR | NR | NR | · | · | 1 |
| Toluene | · | · | · | NR | · | NR | NR | NR | · | |
| Town Gas | · | · | · | · | · | · | NR | · | · | |
| Trichlorethylene (Dry) | NR | NR | NR | NR | · | NR | NR | · | · | |
| Turpentine | · | · | · | NR | · | · | NR | · | · | |
| Vegetable Oil | NR | NR | NR | NR | · | · | NR | · | · | |
| Vinegar | NR | NR | NR | NR | · | NR | · | NR | · | 1 |
| Water (Mains) | NR | · | · | · | · | · | · | · | · | |
| Water 80 – 120°C | NR | · | · | NR | · | NR | · | · | · | |
| Water 120 – 150°C | NR | · | · | NR | · | NR | NR | · | · | |
| Water 150 – 180°C | NR | · | · | NR | · | NR | NR | NR | · | |
| Water Boiler Feed | NR | NR | NR | NR | · | · | · | NR | · | |
| Water/Glycol Solutions | NR | · | · | NR | · | NR | · | · | · | |
| White Spirit | · | · | · | · | · | NR | NR | · | · | |
Notes:
1. Non-standard materials of construction are required.
2. Chlorine must not exceed 5 parts per million
3. We are required to provide industry standard degreasing, cleaning and individual packaging with the appropriate label.
Key;
· = Recommended
NR = Not Recommended
To ensure the correct selection of compatible valve and seal, please contact our technical team on 01234 855888 or email sales@v-flowsolutions.co.uk
You can read part 5 of our solenoid valve guide here
