Abb. 1: Flow-Stop-Ventil mit externer Ansteuerung

Abb. 2: Diagramm zur Einstellung des max. Durchflusses

| Product information

Pump Control Innovation. New valve series for dry run protection

"Many customers are looking for a more precise compressed air provision in pump controls", explains Gerd Baumeister, Sales Executive at KNOCKS. The dry run protection Flow-Stop valve is our latest development at KNOCKS Fluid-Technik GmbH and fulfils exactly that requirement.

Flow-Stop is a valve with a control option that allows a limiting of the max. throughput to a specified value. Once this max. value is surpassed, e.g. due to a lack of pump medium, then the system automatically shuts down to preventa pump overload or any damage to the pump.


The system will only resume operation once a pneumatic button is pressed. The restart occurs via an optional control valve or a start impulse on an external switch valve. This system layout ensures maximised system protection and complies with regulatory requirements for work safety and with the ATEX product guideline 2014/34/EU.


"A special feature of Flow-Stop: The valve is a modular component and can therefore be integrated in virtually any maintenance unit, allowing a customised provisioning of compressed air to ensure highest safety for the application", explains Dirk Heinrich, Head of Development at KNOCKS.


Use and areas of application


The Flow-Stop valve can be implemented in any system that could suffer damage to components or endanger personnel if volume flows were to exceed desired numbers. Mechanical stresses, e.g. flexing or vibration, thermal loads from heating processes, chemical stress from acids and bases, as well as material fatigue and external force impact on compressed air lines pose dangerous threats.


The result could be a burst pressure hose. A sudden drop in pressure in the work line in conjunction with excessive volume flow will activate an immediate shut-down of the Flow-Stop valve. The burst line is without pressure - and the danger is in check. The device was developed in response to calls for maximised system safety.


Another meaningful application would be for compressed air membrane pumps or piston pumps in spray painting or conveyor technology. Once a paint container has been emptied, the idling speed of the pump will increase, which could in extreme cases result in the destruction of the pump. Flow-Stop responds to the changed pressure or volume flow situation and shuts down the compressed air supply automatically - the pump is safe.


Function and valve settings


A spring mounted inside the Flow-Stop valve is pre-tensioned by turning a hand wheel to set the max. acceptable pressure drop or volume flow. Once Flow-Stop has responded and closed, it can only be reactivated via a RESET button. The RESET button controls a separate control valve, which, when active, allows compressed air into the control space of the valve and switches the valve to throughput.


Advantages of Flow-Stop in comparison with competitor products


  • High settings sensitivity for the desired volume flow or flow stop
    (sensitive response characteristic)
  • Uncomplicated, easy to follow operation
  • Visually elegant solution due to functional integration in the central pump control system
  • Instant, reliable shut-down behaviour
  • Controlled restart via the RESET function


If you don't ask you won't find out!

Our dedicated engineers are happy to assist you and provide you with additional information about our products and services.

Please send your e-mail enquiry to


It is better to find what you're looking for quickly than to spend a long time searching!

Our product finder offers you easy search options to ensure fast, targeted access to your desired product.

to the product finder

We keep you informed!

Subscribe to the KNOCKS-Newsletter and receive always the latest news about KNOCKS.

Sign up for the NEWSLETTER here!

I hereby confirm that I have read the privacy policy and the information contained therein.