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Valves — Precision, Material Selection, and Installation Conditions for Industrial Applications

Valves control, shut off, and regulate media flows in industrial processes. Key factors are material compatibility, pressure and temperature resistance, design, and connection type. On this category page, you will find valves for pneumatics, hydraulics, compressed air, gases, and liquids, with a focus on industrial series production and plant construction. Selection is based on the medium, operating conditions, leakage risk, and maintenance intervals.

Materials and Corrosion Behavior

The selection of material and surface treatment determines service life and tightness. For neutral gases and non-aggressive liquids, brass and aluminum are frequently used. For hydrogen, chlorine-containing media, saltwater, or acids, stainless steels (1.4301 / 304, 1.4404 / 316L) or high-alloy materials are required. For abrasive media, hard-coated materials or ceramic inserts are advisable. Elastomeric seals (NBR, EPDM, FKM/FPM, PTFE linings) must be chemically compatible with the medium and meet temperature/aging requirements. Example: In cooling circuits with glycol, EPDM seals are common; for oils and fuels, FKM seals are required.

Designs and Functional Types

Valves differ functionally: shut-off valves (ball valve, gate valve), control valves (needle valve, diaphragm valve), diverting valves, and solenoid valves. Ball valves offer quick, media-separating shut-off with low pressure loss; gate valves are robust when exposed to solids. Control valves with precise adjustment characteristics are suitable for flow, pressure, or temperature regulation. Solenoid valves are the first choice for automation, offering fast switching times and easy electronic control, but require clean media or integrated filters.

Connections, Installation Position, and Installation Space

Connection types influence assembly effort and sealing behavior: threaded connections (G, NPT), flanges (DIN EN), screw-in or plug connections, as well as compression and quick couplings. Thread seals should be chosen to match the design (PTFE tape, metal or elastomer seal). For flange connections, seals must be specified in terms of material and hardness. The installation position can affect the function of gravity-dependent valves; diaphragm and float valves require defined orientations. Pay attention to installation space for actuators, handwheels or electric drives, as well as cable routing and service accessibility.

Seals, Leakage Rates, and Certifications

Sealing materials determine permissible leakage rates. For vacuum applications or flammable gases, metallic seals or hermetic designs are required. Gas permeability and permeation play a role in inert gas or shielding gas applications. For food and pharmaceutical applications, FDA/USP-compliant materials and surface roughnesses are defined. Valves for safety-critical applications should have relevant approvals (ATEX, PED, ISO/TS, SIL level for control engineering applications).

Maintenance, Replacement Cycles, and Spare Parts

Accessibility for routine maintenance influences plant availability. Valves with modular sealing kits allow quick replacement without removing the housing. Spare parts should be easy to order and clearly marked. Lubricants in moving parts must be compatible with the medium and seals. As part of predictive maintenance, documentation of operating hours, switching cycles, and pressure surges is recommended to detect premature wear.

Performance Indicators and Design

Relevant for design are Kv value (flow coefficient), max. operating pressure, nominal size (DN), temperature range, switching time, and permissible pressure losses. Kv values must be related to operating conditions (viscosity, differential pressure). For control valves, the characteristic curve (linear, equal percentage) is crucial for process stability. Consider pressure surges (water hammer) and material fatigue with frequent switching.

Practical Application Examples

Example 1 — Production Line for Cooling Systems: In a line system for assembling coolers, a pneumatically actuated diaphragm valve regulates the coolant inflow. The valve is made of 316L with an EPDM seal to ensure corrosion resistance and glycol compatibility. Adjustable position feedback is electronically reported back to the PLC. During cleaning steps, an additional shut-off ball valve module allows safe isolation of the section without emptying the entire line. Example 2 — Paint Shop: In a paint shop, magnetic 2/2-way valves control the solvent flow. The valves are equipped with integrated fine filters and a PTFE-lined seat to prevent blockages and abrasion. Final shut-off is performed by flanged ball valves for quick cleaning access. Material choice: Stainless steel 316L and FKM seals for solvent resistance. Example 3 — Gas Distribution in Production Halls: In a production layout, safety shut-off valves with position monitoring are used to isolate combustible gases zone by zone. Valves are gas-tight tested, with low leakage values and ATEX-compliant electric actuators. Maintenance-free bearings and redundant sealing systems reduce failure risks.

Integration into Automation and Control

For Industry 4.0 applications, valves with feedback signals, digital control, and diagnostic functions are preferable. Electric actuators with IO-Link or Profinet enable parameterization and remote diagnostics. Solenoid valves with current monitoring report short circuits or coking. When integrating safety-relevant functions, valves with certified position monitoring and emergency stop functions are necessary.

Procurement Criteria and Documentation

Before ordering, specific parameters must be defined: medium, max. pressure, temperature, flow, nominal size, connection type, material, seal type, switching frequency, and certification requirements. Request technical data sheets, exploded drawings, and material certificates. For series projects, a coordinated spare parts package is economically sensible. Further technical information and configuration aids can be found at https://maku-industrie.de/technik and specific application examples at https://maku-industrie.de/anwendungsbeispiele.

Selection Aid in One Sentence

* Choose material and seal according to medium and temperature, design according to application (shut-off vs. control), connection according to assembly and maintenance requirements, and pay attention to certifications for safety and admissibility.

FAQ

1. Which seal is suitable for high temperatures and aggressive media? For high temperatures and chemical resistance, FFKM (perfluoroelastomer) or PTFE-lined seals are the first choice. For moderate temperatures and polar media, EPDM can be useful; for mineral oils and fuels, FKM. 2. How do I determine the correct Kv value for a valve? Calculate the Kv value based on the desired flow at a defined differential pressure (Kv = Q / sqrt(Δp), Q in m3/h, Δp in bar). Consider medium viscosity and operating point; for control valves, choose a characteristic curve that allows stable control ranges. 3. When are magnetic valves unsuitable and what is the alternative? Solenoid valves are unsuitable for heavily contaminated, abrasive, or very viscous media, as well as for high pressures beyond manufacturer specifications. Alternatives are pneumatic control valves, gate or diaphragm valves with suitable materials and robust seat seals.