Manually-operated valves with slide valve or level

Ordering Manual Directional Control Valves with Toggle Lever or Slide Valve

Manually operated directional control valves from Parker Legris are compact, robust solutions for targeted control and venting of pneumatic outlet lines. They are offered as **3/2 supply directional control valves**, **3/2 exhaust directional control valves**, or as pure **2/2 directional control valves**, differing in circuit diagram, seal design, and actuation type. In industrial manufacturing environments, these valves secure pressure-holding and venting functions, enable manual releases in maintenance processes, and serve as immediate switching points in manual workstations and test benches.

Construction and Materials

The valves are based on housings made of brass, aluminum, or technical plastics such as POM or PA, depending on the design for pressure, media resistance, and weight. Brass housings combine high pressure resistance with good corrosion resistance in general industrial environments. Aluminum housings reduce weight while maintaining high stability, useful in robotic or handling applications where moving masses need to be reduced. Plastic housings are used when chemical resistance to cleaning agents or cost-effective spare parts are required. The internal valve seats are often made of hardened steel or stainless steel for higher demands on wear resistance and temperature changes. The sealing materials used are crucial for leak-tightness. NBR (nitrile rubber) is standard for oil- and compression-resistant pneumatic applications. FKM/FPM offers higher temperature and chemical resistance and is chosen in process environments with more aggressive media. EPDM is recommended for steam applications and generally for water contact. Parker Legris uses standardized sealing variants depending on the type; special seals for specific media are available if required.

Actuation Types: Toggle Lever vs. Manual Slide Valve

**Toggle levers** are tactile, quick-acting, and allow precise one-hand operation. They are mechanically robust and easy to operate even with gloves due to lever transmission. Toggle lever valves are suitable for applications where a defined zero or rest state must be maintained, such as safety switches during maintenance work or manual presets at assembly stations. **Manual slide valves** offer variable positioning and are often available with detents for multiple switching positions. They are preferred when continuous, manual throttling or holding an intermediate switching position is required, for example, in test benches for gradual pressure build-up control.

Connections, Designs, and Integration Options

Typical connection types include threaded connections (G, BSPP), NPT for international applications, quick connectors according to ISO/VDI, and push-in connectors for PE/PU hoses. When selecting, hose diameter, medium temperature, and mounting accessibility are crucial. Valves are available in inline and angled designs; angled housings reduce pipe runs and save space in confined machine compartments. The modular design allows combination with mounting plates or control cabinet mounting, as well as integration into pneumatic manifold blocks. For automated systems, mechanical stops and detents are available to ensure reproducible manual operation. * Common connection variants: G1/8, G1/4, M5, Push-In 4/6/8 mm

Sealing and Switching Characteristics

The switching characteristics of Parker-Legris manual valves are designed to minimize switching times and keep leakage rates low. Designs with soft seats (elastomer seats) provide good sealing at low contact pressure; hard seats (metal-on-metal) reduce wear and erosion risks with abrasive media. Leakage rates are specified in standards such as ISO 6358; tested low-leak variants are available for pressure-critical applications. Spring travel and stroke at the actuator are optimized to ensure defined switching behavior even after prolonged use.

Application Fields and Practical Scenarios

In robotics, manual directional control valves are often used as local emergency shutdowns on grippers or tools. There, a **3/2 exhaust directional control valve with toggle lever** ensures rapid pressure relief of the suction cups during tool changes; the valve is ergonomically positioned on the robot arm and allows the operator to manually vent the suction cup without opening the control system. In the textile industry, manual slide valves are used for fine adjustment of pneumatic clamping devices on weaving and winding machines. By gradually opening, material tensions can be controlled and reduced without stopping the overall process. In printing presses, manual **2/2 directional control valves** enable local isolation of compressed air circuits during tool changes or sensor replacement. Compact brass valves with push-in connectors are common there because quick disassembly and low leakage are required. In plastics processing, robust aluminum housings with FKM seals are used to tolerate temperature peaks at the tool edge and possible contact media. In assembly stations and test benches, manual directional control valves are used as operator-proximate release elements to selectively activate or vent pneumatically operated devices.

Practical Examples: Structured Scenarios

Example 1 — Robot Tool Change: A gripping tool on an industrial robot is equipped with a G1/8-3/2 exhaust toggle lever valve on the arm. Before the manual tool change, the robot is moved to a safe position. The fitter presses the toggle lever; the valve locally vents the suction cup line, and the gripper releases the workpiece. After replacing the tool, the valve is reset, the supply air is closed again, and the robot resumes the cycle. Example 2 — Test Bench Calibration: A manual slide valve is integrated into the pressure supply of a measurement test. During calibration, the technician gradually moves the slide sleeve to increase the pressure in six steps and record the measurement curve. The switching position is held lockable at each step to ensure reproducible measurement data. Example 3 — Downtime Release in the Production Line: For maintenance of a production line, individual pneumatic sub-circuits are isolated. 2/2 directional control valves with Push-In 6 mm connections enable quick disconnection of the lines; technicians can thus specifically release pressure and safely replace components without shutting down the main supply. Further technical information and application examples can be found under Technology and Application Examples on our website.

Selection Criteria and Ordering Information

When selecting, consider the operating pressure range, nominal size, connection type, sealing material, and ambient temperature. Choose toggle levers for frequent actuation with a clearly defined switching point, and manual slide valves if intermediate switching positions or finer adjustment are required. Check the compatibility of the seal (NBR, FKM, EPDM) with cleaning and process media. Pay attention to the mounting type and space requirements; angled housings save installation space, while inline models facilitate retrofitting. For safety-relevant applications, parts with a specified leakage class and documented test results are recommended.

Maintenance and Service Life

Maintenance intervals depend on switching cycles and load. Regular functional and leak tests extend service life. Replace seals when visible wear occurs or when leakage rates increase. Clean valve housings of deposits and foreign bodies; in dusty environments, additional filters in the supply air lines are advisable. For high cycle numbers, selecting wear-resistant seat materials and, if necessary, pre-lubricated variants is recommended to reduce dry wear.

Compatibility with System Components

Parker Legris manual valves can be easily combined with standard cylinders, pneumatic distributors, and sensors. Check interfaces for threads and hose diameters, as well as the installation position in control topologies. Documentation and CAD data are available for integration into complex systems; individual adjustments are possible if required.

FAQs

**1. Which seal should I choose for aggressive cleaning agents?**
For aggressive cleaning agents, FKM/FPM is recommended, as this material offers higher chemical and temperature resistance. EPDM is only suitable to a limited extent, and NBR is suitable for oil-based media. **2. When is a 3/2-way valve preferable to a 2/2-way valve?**
A 3/2-way valve is preferable when separation or venting functions are needed (e.g., exhaust function), or when a rest position with a vented line is desired. A 2/2-way valve is sufficient if only on/off switching without separate venting is required. **3. Which connection type offers the fastest assembly in production?**
Push-in connections offer the fastest assembly and disassembly at the production level because they are connected without tools. Threaded connections are more robust against vibration and are suitable for permanently tight connections in harsh environments.