H-QS-8 Festo Check valve

Technical Overview

The Festo H-QS-8 is a high-performance check valve designed for pneumatic systems requiring a reliable non-return function. It features an anodized aluminium housing in a black finish and utilizes QS-8 push-in connections for simplified in-line installation. This valve is engineered to operate within a pressure range of -1 to 10 bar and supports a standard nominal flow rate of 681 l/min, making it suitable for a variety of industrial automation applications.

Key Features

Non-return function
QS-8 push-in connections for both ports
In-line installation type
Anodised aluminium housing material
RoHS-compliant material construction
VDMA24364-B1/B2-L LABS (PWIS) conformity
Lubricated operation possible

Technical Specification Matrix

Parameter	Value
Valve function	Non-return function
Pneumatic connection, port 1	QS-8
Pneumatic connection, port 2	QS-8
Type of mounting	In-line installation
Standard nominal flow rate (standardised to DIN 1343)	681 l/min
Operating pressure	-1 bar ... 10 bar
Ambient temperature	0 °C ... 60 °C
Material housing	Anodised aluminium
Housing colour	Black
Operating medium	Compressed air to ISO 8573-1:2010 [7:-:-]
Symbol	00991455
Min. diff. pressure, opening	0.1 bar
Min. diff. pressure, closing	0.2 bar
Note on operating and pilot medium	Lubricated operation possible (in which case lubricated operation will always be required)
LABS (PWIS) conformity	VDMA24364-B1/B2-L
Product weight	21 g
Note on materials	RoHS-compliant

Industrial Applications

1. Energy-Efficient Vacuum Gripping System

Integration into the suction line of a robotic vacuum gripper to maintain negative pressure when the vacuum generator is deactivated. The valve is installed between the vacuum ejector and the suction cup.

Problem Solved

Prevents the dropped parts and reduces air consumption. Without the valve, the vacuum generator must run continuously to hold the part. The H-QS-8 traps the vacuum (-1 bar capability) at the cup, allowing the ejector to switch off (energy saving) while securely holding the payload.

Vacuum retention-1 bar operating pressureQS-8 push-in connectionPick-and-place safety

2. Mobile AGV Pneumatic Reservoir Isolation

Used at the charging port of a mobile Automated Guided Vehicle (AGV) that utilizes compressed air for braking or lifting mechanisms. It permits the onboard tank to fill from a docking station and seals immediately upon disconnection.

Problem Solved

Enables rapid charging of the onboard pneumatic system without manual intervention or air loss during undocking. The high nominal flow rate (681 l/min) supports fast refill cycles, while the non-return function ensures the AGV retains braking pressure (up to 10 bar) after leaving the station.

Supply line isolation681 l/min flow rate10 bar pressure ratingMobile robotics

3. Pneumatic Clamping Pressure Protection

Installed upstream of a pneumatic clamp cylinder in a machining fixture. It isolates the clamping circuit from the main air supply network.

Problem Solved

Prevents workpieces from coming loose due to pressure fluctuations in the main plant supply (e.g., when a nearby high-consumption machine activates). The low opening pressure (0.1 bar) ensures the clamp receives near-maximum force, while the valve blocks backflow if the supply pressure momentarily drops below the clamped pressure.

Pressure retention0.1 bar cracking pressureBackflow preventionWorkholding safety