MSTV Series Modular Solenoid Operated Throttle Valves

Overview

The MSTV Series is an advanced modular stackable electro-hydraulic throttle valve designed for automated flow control in modern hydraulic systems. This compact sandwich-type valve combines manual flow adjustment capability with solenoid-actuated switching, enabling remote or programmed control of actuator speeds. The MSTV valve integrates seamlessly into NG6/Cetop 3 modular valve stacks, providing a space-efficient solution for applications requiring dynamic speed regulation without manual intervention.

Key Functions

Working Principle

The MSTV valve operates through a dual-control mechanism:

Manual Adjustment Phase

• Operator rotates the knurled knob to mechanically set the desired throttle opening

• This establishes the maximum restricted flow rate available when the valve is activated

• Setting is locked to prevent drift from vibration or pressure fluctuations

Electrical Control Phase

• De-energized State: Valve maintains default position (typically full flow bypass or complete restriction depending on configuration)

• Energized State: Solenoid shifts internal spool, engaging the preset throttle restriction

• Coil options: 12V DC, 24V DC, 110V AC, 220V AC with DIN 43650 connector standard

Flow Control Characteristics

• Throttling action creates pressure differential across the valve

• Resulting flow limitation directly controls actuator velocity

• Bi-directional design ensures consistent speed regulation in extend and retract strokes

Primary Applications

1. Automated Production Machinery

• Enables two-speed operation in CNC machine tool feed systems

• Provides automatic rapid-to-feed transition without operator intervention

• Synchronizes multiple actuator speeds through PLC-controlled timing

2. Injection Molding Systems

• Automates mold closing speed profiles (fast approach → slow clamp)

• Controls ejector sequence timing for optimized part removal cycles

• Manages core puller operations in multi-stage mold actions

3. Mobile Hydraulic Equipment

• Enables automated boom/arm speed selection on excavators and cranes

• Provides creep speed mode for precision positioning operations

• Supports remote radio control of hydraulic functions

4. Packaging & Material Handling

• Controls conveyor lift speeds in automated warehouse systems

• Manages palletizer layer-forming speeds for product protection

• Regulates stretch wrapper arm rotation speeds

5. Test & Simulation Equipment

• Enables programmed load application rates in hydraulic test frames

• Controls motion profiles in flight/vehicle simulators

• Provides repeatable speed sequences for quality assurance testing

Detailed Usage Scenarios

Scenario A: Automatic Rapid-Feed Transition

Configuration: MSTV mounted between directional valve and cylinder
System: Automated CNC machining center
Operation Sequence:
1. Rapid Approach: Solenoid OFF → Full flow → Fast tool positioning
2. Working Feed: Solenoid ON → Throttled flow → Controlled machining feed
3. Rapid Retract: Solenoid OFF → Full flow → Fast return stroke
Integration: M-code or PLC output triggers solenoid at programmed position
Benefit: Eliminates manual feed rate changes, reduces cycle time, improves surface finish

Scenario B: Safety-Interlocked Speed Control

Configuration: MSTV with normally-closed throttle preset
Application: Hydraulic press with light curtain safety system
Safety Logic:
- Light curtain clear: Solenoid energized → Normal operating speed
- Light curtain interrupted: Solenoid de-energized → Immediate slow speed (or stop)
- Manual reset required to return to normal operation
Compliance: Meets Category 3 safety requirements per ISO 13849

Scenario C: Multi-Stage Motion Profiling

Configuration: Two MSTV valves in parallel with different throttle settings
Application: Large injection molding machine mold closing
Stage 1: Both solenoids OFF → Maximum speed → Fast approach
Stage 2: Solenoid A ON (light throttle) → Reduced speed → Mold contact
Stage 3: Solenoid B ON (heavy throttle) → Slow speed → High-pressure clamping
Result: Smooth, programmable speed profile without complex valving

Scenario D: Remote Speed Selection

Configuration: MSTV in mobile hydraulic crane hoist circuit
Control: Radio remote transmitter with speed select button
Operation:
- Normal button: Solenoid OFF → Standard lifting speed
- Creep button: Solenoid ON → Reduced speed for precision placement
- Operator maintains visual contact while controlling speed remotely
Advantage: Single actuator provides dual speed capability without mechanical transmission

Scenario E: Energy-Efficient Idle Operation

Configuration: MSTV in hydraulic pump unloading circuit
Application: Large machine tool with intermittent cutting cycles
Logic:
- Cutting active: Solenoid ON → Full system pressure to feed cylinder
- Cutting idle: Solenoid OFF → Restricted flow maintains position with minimal energy
- Reduces pump heat generation and energy consumption during dwell periods

Technical Advantages

Installation & Commissioning Guidelines

Electrical Connection

• Verify coil voltage matches control system specification before energization

• DIN 43650 connector provides IP65 protection when properly seated

• Recommended: Install surge suppression diodes on DC coils to protect PLC outputs

Hydraulic Integration

• Meter-In Mounting: Between pump and directional valve (controls incoming flow)

• Meter-Out Mounting: Between directional valve and actuator (preferred for load holding)

• Ensure proper port alignment: P (pressure), T (tank), A & B (actuator ports)

Adjustment Protocol

1. With solenoid de-energized, verify full flow condition

2. Energize solenoid and adjust knob to achieve desired restricted flow

3. Measure actuator speed with flow meter or timing verification

4. Lock adjustment and document setting for maintenance records

5. Test fail-safe return to default state upon power interruption

Troubleshooting Reference

Model Designation System

The MSTV Series bridges the gap between simple manual throttle valves and expensive servo-proportional systems, offering equipment builders a cost-effective path to automated hydraulic control. Its robust construction and straightforward electrical interface make it ideal for both OEM applications and retrofit upgrades to existing machinery.