Stop valves of the Metal Work Line-on-Line series
It is available in a version for pipe-pipe connection, which includes two push-in fittings, and a version for thread-pipe connection, which includes a nickel-plated brass male thread and a push-in fitting.
The stop valve is normally mounted on the inlet port of cylinders and allows the flow of air only in the presence of a pneumatic pilot. Cylinder movement ceases if there is a drop in pneumatic pilot pressure
The compressed air port is a push-in fitting for Ø 4 pipe.
This stop valve is available in a unidirectional version, so the flow can be interrupted in one direction, but remains free in the other direction.
This valve can also be used as a unidirectional normally-closed 2/2 pneumatic control valve.
9065710 – IN-LINE STOP VALVE thread-pipe 1/8-Ø8
9065712 – IN-LINE STOP VALVE thread-pipe 3/8-Ø8
9065709 – IN-LINE STOP VALVE thread-pipe 1/4-Ø6
9065711 – IN-LINE STOP VALVE thread-pipe 1/4-Ø8
9065808 – IN-LINE STOP VALVE pipe-thread Ø6-1/8
9065809 – IN-LINE STOP VALVE pipe-thread Ø6-1/4
9065810 – IN-LINE STOP VALVE pipe-thread Ø8-1/8
9065812 – IN-LINE STOP VALVE pipe-thread Ø8-3/8
9065811 – IN-LINE STOP VALVE pipe-thread Ø8-1/4
9065708 – IN-LINE STOP VALVE thread-pipe 1/8-Ø6
Stop Valves: Precise Shut-off and Reliable Flow Control
Stop valves ensure the reliable interruption of media flows in pneumatic, hydraulic, and fluid-carrying systems. In industrial manufacturing environments, they are central components for assembly lines, test benches, compressed air distribution, and media supply. Key selection criteria include operating pressure, medium, temperature range, connection type, and sealing material. Stop valves differ in design, actuation type, and sealing concept and must be matched to process requirements to minimize leaks, pressure losses, and downtime.
Materials and Material Selection
The choice of material depends on the corrosion resistance, mechanical strength, and contamination requirements of the medium. Common materials include brass, stainless steel (1.4301 / AISI 304, 1.4404 / AISI 316L), aluminum alloys, and technical plastics such as PEEK or PVDF. For aggressive media or hygienic applications, stainless steel 316L is often required. Brass offers a favorable price-performance ratio for general compressed air and water systems. Plastic housings are used when metallic contamination must be avoided or weight reduction is crucial. Materials also influence the permissible operating temperatures and tensile strength for threaded and flanged connections.
Designs and Functional Principles
Stop valves are available as globe valves, angle valves, needle valves, and ball valves. Globe valves offer straight-through flow and low flow resistance. Angle valves minimize installation dimensions in confined spaces. Needle valves allow finely adjustable flow control and are suitable for balancing compressed air or fluid flows. Ball-operated stop valves enable quick, full-surface shut-off with minimal leakage rates. The sealing principle is crucial: metallic seat seals achieve high temperature resistance, while elastomer-based systems (NBR, EPDM, FKM/FPM) offer better sealing with low installation effort.
Connections and Installation Dimensions
Connection systems vary between threaded connections (G, NPT, BSP), flange connections according to DIN/EN standards, quick couplings, and pipe fittings with cutting rings or clamping technology. Threaded connections are compact and universal, flange connections offer larger sealing surfaces for high pressures and facilitate disassembly. Quick couplings are preferred when frequent changes or maintenance are required. For pneumatic stop valves, standard sizes such as G1/4 or G1/8 are common; hydraulic stop valves often require robust flange solutions. When selecting, consider the installation length, the required clearance, and the orientation for operating levers or pneumatic cylinders.
Seals and Service Life
Sealing materials determine chemical resistance, temperature resistance, and friction properties during closing and opening. NBR is economical and suitable for mineral oils, compressed air, and water up to moderate temperatures; EPDM resists heat, steam, and many chemicals; FKM/FPM (Viton) covers high temperatures and aggressive media; PTFE offers excellent chemical resistance and low friction, but increased pre-tension for elastic recovery. The combination of metal-PTFE seats with elastomeric O-rings combines sealing with temperature tolerance. For frequent switching operations, wear-resistant seat designs and replaceable seals are crucial for cost-effectiveness.
Actuation Types and Automation
Stop valves are available with manual, pneumatic, electric, or hydraulic actuation. Manual hand levers or handwheels are cost-effective and easy to integrate. Pneumatic actuators enable fast response times and simple control using 5/2-way or 3/2-way valves. Electric actuators offer precise positioning, easy integration into PLC systems, and telemetry. For critical processes, end position sensors, position switches, and feedback systems are recommended. For automation, the interface between valve and actuator must be considered: standard flanges, positioners, and mechanical couplings must be compatible.
Application Areas and Examples of Use
In assembly islands, stop valves control individual workstations to selectively shut off compressed air, thereby reducing energy consumption. In test benches, they serve to safely isolate test specimens before and after measurements. In cooling circuits of machine tools, they enable targeted disconnection of individual circuit segments for maintenance without interrupting production. In paint booths, chemical-resistant stop valves secure the detachment of paint media and trigger safety shutdowns if necessary. In cleanroom processes, valves with metallic seat seals minimize particle formation.
Practical Examples
Practical Example 1 — Assembly Line Compressed Air Distribution: In an assembly line, a pneumatic stop valve with a G1/4 screw connection and NBR seal is installed, controlled by a 5/2-way solenoid valve. During cycle changes, the stop valve shuts off individual workstations, reduces leakage losses, and enables quick maintenance isolation without plant downtime. The compact design reduces pipe length and improves response times.
Practical Example 2 — Hydraulic Test Bench: A stainless steel stop valve with DN25 flange connections and PTFE seats separates the test specimen circuit from the main system. The valve is electrically actuated with end position sensors to synchronize exact pressure releases during test cycles. The material choice (1.4404) prevents corrosion from emulsified test media, and the PTFE seals ensure leak-free operation at high pressures.
Practical Example 3 — Coolant System in Machine Tool: A brass needle stop valve regulates the volume flow of a water-based coolant. The fine adjustability enables temperature-stable conditions at the tool tip. During maintenance, the valve is closed, the affected circuit is drained, and the machine remains operational for the rest of the line.
Testing and Maintenance Requirements
Stop valves should be checked for tightness, mechanical actuation, and wear at defined intervals. Visual inspection, functional testing of the actuation mechanism, and leak testing under operating pressure are standard. Replaceable sealing elements enable quick on-site repair. For safety-relevant applications, a documented test plan with pressure and leak rate measurements and logging of actuation cycles is recommended.
Safety and Standard Requirements
Select stop valves according to relevant standards (e.g., DIN EN, ISO) and check certifications for pressure equipment, food suitability, or ATEX zones if explosive media are present. Document operating limits such as maximum operating pressure, temperature range, and medium compatibility. For safety-critical shut-offs, redundancy concepts or double-acting valves with automatic interlocking are advisable.
Selection Criteria and Decision Factors
Selection depends on operating pressure, flow requirement, medium, temperature, installation space, and degree of automation. Consider the interaction of material and seal, as well as the connection type in relation to installation effort. Economic life cycle costs result from material selection, ease of maintenance, and availability of replacement seals. Technical data sheets provide information on Kv value, switching cycles, and permissible pressures, which must be matched with actual process conditions. Further technical information and specifications can be found at https://maku-industrie.de/technik and practical application examples at https://maku-industrie.de/anwendungsbeispiele.
Quick Overview of Important Features
- Materials: Brass, Stainless Steel 1.4301/1.4404, PEEK, PVDF
- Seals: NBR, EPDM, FKM/FPM, PTFE
- Connections: G/BSP/NPT, Flange according to DIN, Quick Coupling
- Actuation: Manual, Pneumatic, Electric, Hydraulic
- Types: Ball Valve, Needle Valve, Globe and Angle Valve
FAQs
1. Which stop valve is suitable for compressed air in assembly plants?
Choose a valve with a brass or stainless steel housing and NBR or FKM seals depending on temperature and lubricant content. Common connections are G1/4 or G1/8; pneumatically actuated versions with quick couplings allow for easy integration and fast switching times.
2. How do I differentiate stop valves for hydromechanical test benches?
For test benches, valves with high permissible operating pressure, stainless steel housing, and PTFE or metallic seat seals are preferred. Electric actuation with position feedback ensures reproducible test conditions. Flange connections facilitate disassembly and leak testing.
3. Which seal is recommended for chemically aggressive media?
For aggressive media, PTFE is the first choice due to its broad chemical resistance. FKM/FPM is suitable for organic solvents and higher temperatures. EPDM offers advantages for steam and aqueous media. Material data sheets and compatibility lists must always be compared with the specific medium.