Festo VHER Hand Lever Valves

The Festo VHER hand lever valve is a manual pneumatic control device that can be operated by a lever. The valve features a rotary gate valve design. The valve is available in different configurations, including 4/3-way and 3/3-way functions, with options for mid-position closed, exhausted, or pressurized states. This flexibility allows it to control both single-acting and double-acting cylinders effectively. The Festo hand lever valve can be used to stop these cylinders within the stroke range, offering more precise control in pneumatic systems. The ability to control the piston movement in the mid-position (either closed or exhausting) provides additional functionality for fine-tuning pneumatic operations.

Note: The Festo VHER hand lever valve is available in two forms - VHER metric and VHER inch. The only difference between them is the measurement system used. The metric version uses millimeters and centimeters, while the inch version uses inches and fractions of inches.

Festo VHER hand valve key features

• Powerful performance: Flow rate of 170 to 3800 l/min for efficient operation
• Flexible connectivity: Available connections include M5, G1/8, G1/4, and G1/2
• Versatile configuration: The valve can function as a 4/3-way valve or a 3/3-way valve.
• Practical applications: Suitable for stopping single-acting cylinders or double-acting cylinders within the stroke range.
• Lever mechanism: The lever is available in two versions: metal and polymer.
  • Metal: Choose metal handles if the application demands high durability, strength, higher actuating torque, and temperature stability. They are ideal for heavy-duty industrial applications where robustness is crucial.
  • Polymer: Choose polymer handles if the application needs a lightweight, cost-effective solution with good corrosion resistance and the option to lock the actuator. They are suitable for general-purpose applications where weight and cost are important factors.
• Detenting function: The VHER series includes a detenting mechanism. "Detenting" refers to a mechanical feature that allows the valve to stay in a selected position without the need for continuous manual force. This means that once the lever is moved to a particular position, it will "click" into place and remain there until it is manually moved again.This is particularly useful for applications requiring stable and consistent flow control.
• Multiple mid-position states: The VHER valves offer different mid-position states (pressurized, closed, or exhausted), providing more control options (discussed later).
• Dual-pressure operation: The VHER-B43 valves support dual-pressure operation. The compressed air can be applied to ports 1 and 3. However, the higher pressure must always be applied to port 1.
• Vacuum compatibility: The VHER valves are designed to handle vacuum operations, with specific ports designated for vacuum connection.

Festo VHER hand valve states

The mid-position state of a valve refers to the condition of the valve when it is in its neutral or central position. For the Festo pneumatic hand lever valves, there are three possible mid-position states: pressurized, closed, and exhausted. Each state offers different control options and functionalities, which can be crucial for various pneumatic applications. Each valve is designed to operate with one specific mid-position state.

Mid-position pressurized (B43U)

• In this state, the valve allows air pressure to be applied to both sides of the actuator or cylinder.
• Both ports connected to the actuator are pressurized.
• This can be used to hold the actuator in a fixed position by balancing the forces on both sides.
• Useful for applications where maintaining a specific position is critical, such as in clamping or holding operations.

Mid-position closed (B43C)

• In this state, all ports of the valve are closed, isolating the actuator from the air supply and exhaust.
• The actuator is effectively locked in its current position because no air can enter or leave.
• This is useful for applications where it is necessary to stop the actuator immediately and hold it in place without any movement.
• Prevents any unintended movement due to external forces or pressure changes.

Mid-position exhausted (B43E)

• In this state, the valve allows the air from the actuator to be exhausted to the atmosphere.
• Both ports connected to the actuator are open to the exhaust.
• This allows the actuator to move freely or be manually repositioned, as there is no air pressure holding it in place.
• Useful for applications where it is necessary to relieve pressure from the actuator quickly, such as in emergency stop situations or for manual adjustments.

Table 1: Festo VHER hand lever valve states

Valve function	Description	Use case
4/3-way valve, mid-position closed (B43C)	In the mid-position, all ports are closed.	Ideal for applications to stop the flow completely in the mid-position, such as stopping a cylinder in a specific position.
4/3-way valve, mid-position exhausted (B43E)	In the mid-position, the air is exhausted from the system.	Useful for applications to release pressure in the mid-position, allowing manual movement of the piston by overcoming only frictional forces.
4/3-way valve, mid-position pressurized (B43U)	In the mid-position, the system is pressurized.	Suitable for applications where maintaining pressure in the mid-position is necessary, ensuring that the piston remains in place due to equal pressure on both sides.

Valve function

The Festo VHER valve is typically used as a 4/3-way valve.

• Port 1: Supply port (where the compressed air enters)
• Port 2: Output port 1 (connected to one side of the actuator or cylinder)
• Port 3: Exhaust port (where the air from Port 2 is released)
• Port 4: Output port 2 (connected to the other side of the actuator or cylinder)

Here’s how each configuration works:

Mid-position closed (B43C)

In this position, all ports are closed. This is used to stop the flow of air completely, effectively holding the actuator or cylinder in its current position.

Mid-position exhausted (B43E)

In this position, the air from both output ports (2 and 4) is exhausted to the atmosphere. This is useful for releasing pressure from the system, allowing the actuator or cylinder to return to its default position or be moved manually. The ports are configured as follows:

• Port 1: Closed
• Port 2: Connected to port 3
• Port 3: Open to atmosphere
• Port 4: Connected to port 3

Mid-position pressurized (B43U)

In this position, the supply port is connected to both output ports, pressurizing the system. This is used to maintain pressure in the system, ensuring that the actuator or cylinder remains in its current position due to equal pressure on both sides. The ports are configured as follows:

• Port 1: Connected to ports 2 and 4
• Port 2: Connected to port 1
• Port 3: Closed
• Port 4: Connected to port 4

Practical applications

• Double-acting cylinders: The 4/3-way hand lever valve is ideal for controlling double-acting cylinders, providing precise control over the cylinder's movement by directing air to either side of the piston.
• Directional control: The valve can change the direction of airflow, allowing for forward and reverse motion of the actuator or cylinder.

3/3-way valve function

The Festo VHER hand lever valve can also be used as a 3/3-way valve by closing port 2. The 3/3-way valve configuration can be used to control single-acting cylinders by stopping the flow, exhausting the air, or maintaining pressure.

Vacuum operation

The direction of flow is clearly defined and cannot be reversed. Vacuum must only be connected to port 3, with a filter installed upstream to prevent foreign matter from entering the valve.

Additional features

• Mounting: The valve can be mounted using front panel mounting or through-hole options.
• Accessories: Various accessories are available, including proximity switches, push-in fittings, silencers, and blanking plugs. A switching-position indicator is available with accessories to show the current position or state of the valve.