The medium in contact with the pressure gauge plays a fundamental role in the selection of materials for its internal and external components. For example, brass pressure gauges are ideal for water, air and other non-aggressive liquids or gases. However, in applications where there is exposure to aggressive chemicals such as acid gas, hydrogen sulfide or ammonia, it is essential to opt for more corrosion-resistant materials, such as stainless steel or special alloys such as Monel® (nickel-copper alloy). To prevent fluids from clogging the internal mechanisms, a membrane seal can provide an effective barrier between the fluid and the instrument. Additionally, both the ambient and medium temperatures will determine the type of material that is best suited, as well as the decision to use a dry box or one filled with liquid. Properly selecting materials will prevent leaks and extend the life of the pressure gauge.
Differences between pressure gauge materials
1. Materials for Internal Parts
- Brass (Copper Alloy)
Features: Economical and resistant to corrosion in non-aggressive media.
Applications: Ideal for water, air and non-corrosive gases.
Properties: Good thermal conductivity, but not suitable for aggressive chemicals.
- Stainless Steel (304, 316 Ti)
Features: High resistance to corrosion and high temperatures.
Applications: Suitable for acids, aggressive chemicals and marine environments.
Properties: Durability and mechanical resistance in hostile environments.
- Monel® (Nickel-Copper Alloy)
Features: Excellent corrosion resistance in acidic media.
Applications: Used with hydrogen sulfide, ammonia and aggressive chemicals.
Properties: Great durability in highly corrosive environments.
- Membrane Seal
Features: Acts as a barrier between the fluid and the internal parts of the pressure gauge.
Applications: Recommended for media that can obstruct the pressure gauge mechanism, such as viscous fluids or suspended solids.
Properties: Protects the internal components, extending the useful life of the pressure gauge.
Recommended use: Food, pharmaceutical industry and applications with corrosive fluids.
2. Materials for the Manometer Case
- ABS plastic
Features: Lightweight and impact resistant.
Applications: General non-corrosive environments.
Properties: Limited resistance to chemicals and high temperatures.
- Black Steel
Features Economical and resistant.
Applications: Used in non-corrosive environments.
Properties: Low corrosion resistance.
- PBTP (Fiberglass Reinforced Thermoplastic)
Features: Impact and temperature resistant.
Applications: Used in demanding environments.
Properties: Excellent resistance to chemicals and corrosion.
- Phenolic Box
Features: High thermal resistance.
Applications: High temperature processes.
Properties: Resistant to corrosion, but fragile to impacts.
- Forged Brass
Features: Robust, withstands vibrations and pulsations.
Applications: Heavy machinery and industrial processes.
Properties: High mechanical resistance, but susceptible to corrosion.
- Stainless Steel (304, 316 Ti)
Features: Resistant to corrosion and high temperatures.
Applications: Corrosive environments and with temperature changes.
Properties: Durable and resistant to aggressive chemicals.