Providing Safety
Monitored safety valves

Why use a safety valve with electrical monitoring?

When hydraulic or pneumatic pressure drops, this can lead to unexpected movements with a risk of injury, which is why these systems, like electrical systems, must be designed safely and redundantly

Complies with
Cat. 4/PLe

Hydraulic and

Fluidsentry by Fortress

Safety valves with electrical monitoring

Fluidsentry from Fortress offers a range of highly secure pneumatic and hydraulic electrically monitored safety valves, specially designed for Cat. 4, PLe, and SIL3 applications.

HSV Hydraulic

Hydraulic monitored safety valves 

PSV Pneumatic

Pneumatic monitored safety valves

Zero Pressure Monitor

Feedbacks the isolation status of a hazardous energy system

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Risks associated with hydraulic and pneumatic systems

The use of hydraulics and pneumatics is a reliable and highly precise method of moving loads. However, with all systems, there is a certain risk involved when this force holds a load during the transition between movements.

The most common causes of failures in pneumatic and hydraulic systems are:

  • Contamination caused by hydraulic fluid or internal wear
  • General wear and tear
  • Heat aging
  • Moisture and condensation
  • Poor lubrication

Safety circuits for light curtain

Valve control

Safety circuits for valve monitoring

Valve control

Safety circuits for valve monitoring

Safety circuits for interlock

Highest safety levels

To comply with category 4, ISO 13849-1 requires that the safety-related parts of the control system (SRP/CS) must be designed in such a way that a single fault in this system does not lead to a loss of the safety function.

Additionally, ISO 4413 and ISO 4414 describe in detail how functional safety is the preferred method to mitigate risks associated with hydraulic and pneumatic processes.

Fortress’s Fluidsentry offers secure electrically monitored safety valves for pneumatic and hydraulic systems, specially designed for use on Cat. 4, PLe, and SIL3 applications.

PROFIsafe and CIP safety

The Fortress Fluidsentry safety solution can communicate via the PROFIsafe and CIP safety protocols.

This compatibility allows for seamless integration of the system with existing network control systems that support these protocols, enabling safety information to be communicated quickly and accurately across the networks. This provides several benefits, including rapid detection of hazardous conditions and real-time responses to safety signals.

HSV hydraulische safety valve with electric monitoring

Suitable for demanding applications, FluidSentry safety valves protect your machines and processes from a single fault by depressurising the system and releasing the fluid to a reservoir.

FluidSentry’s monitored valve technology is designed to connect the hydraulic system and electrical safety circuits of machines. According to ISO 13849 and AS4024.1, the double-monitored safety valve systems are also suitable for Category 3 and 4 applications.

Monitors the hydraulic system for malfunctions, leaks and unintended movements.

Different designs

Available in different CETOP sizes ranging from 40LPM to 550LPM.

Safe return hydraulic pressure

Fluidsentry HSV guarantees the safe flowback of hydraulic pressure to the tank by utilizing redundant measures to safeguard against a single point of failure.


Prevent danger

When the electrical signal is deactivated, the fluid supply is blocked and drained to prevent hazardous movements.

PSV Pneumatic safety valve with electrical monitoring

The Pneumatic Monitored Safety Valve (PSV) is a pneumatic safety valve.

This device is designed to ensure safety in pneumatic systems. The safety valve stops the pneumatic flow and brings the system into a safe environment.

The valve is activated when a 24V supply signal is delivered to the PSV. This allows pneumatic energy or fluid power to flow through the system. This is the energised environment where business activities normally take place.

When the 24V supply is removed (de-energised), the PSV is switched off. It has two main consequences:
The downstream system is isolated. The valve prevents further flow of pneumatic energy, isolating the system, and at the same time, the PSV ensures that any residual energy in the system is safely dissipated.

  • It features a dual, independent valve element configuration to provide redundant safety. Available in various valve sizes and can be configured for different pressure ranges.
  • Complies with various international standards and regulations, including the Machinery Directive 2006/42/EC and ISO 13849-1.
  • Suitable for use in a wide range of applications, including factories, production lines, and material handling systems.

Double NC-contacts

The PSV features double NC (Normally Closed) contacts that are directly operated by the valve element during the transition to the output state, and it is monitored in the deactivated state to ensure safety.

Position monitoring

The PSV incorporates a safety-rated device that monitors the position of the valve when it is in the deactivated state to ensure safe operation.

Mechanical bias

The valve is equipped with a mechanical bias that ensures the remaining fluid power is discharged when the valve is no longer powered.

ZPM zero pressure monitoring

How can the monitoring system determine that zero pressure has been reached after isolation? A single- or dual-channel zero pressure monitoring feedback system reports the isolation status of a hazardous energy system.

Safety pressure monitors are made to be integrated into new or existing safety systems where residual pressure needs to be reduced. The monitors have an irregular preset that switches between 3 and 6 psi on pressure reduction and switches between 15 psi on pressure rise. The pressure monitor includes a two-pole positive-drive plunger switch with a pre-approved contact for category 4 safety applications, a positive opening contact.

A single pressure monitor combined with another safety function is suitable for category 2 applications. Two independent units are suitable for category 3 or 4 applications.

Suitable up to Category 4

High-pressure operation up to 340 bar (34,000 kPa).

Detects complete isolation of hazardous fluid power in systems up to Category 4.

Aluminum or stainless steel

The Zero Pressure Monitor for pneumatic applications features an aluminum housing.

The Zero Pressure Monitor for hydraulic applications features a steel housing.

Integration possibilities

Zero pressure monitors are designed to be integrated into new or existing safety systems where residual pressure needs to be discharged.