A client approached our engineering team with a critical safety concern involving the monitoring and control of negative pressure within their ventilation system. The requirement was highly specific: the system needed to detect negative pressure values reaching –70 Pa and respond immediately to protect equipment and ensure operational safety for personnel.
Our task was to design a reliable, safe and technically robust solution that could accurately monitor the pressure and trigger a safety response when the threshold was reached.
The Challenge
The client required:
- Continuous monitoring of negative pressure levels
- Detection of pressure reaching –70 Pa
- Immediate activation of a safety shutdown mechanism
- A solution using available instrumentation and control hardware
Because suitable negative pressure sensors were unavailable, the system required an innovative measurement approach that could deliver accurate readings while maintaining safety compliance.
Our Engineering Solution
To overcome this challenge, we designed and implemented a custom safety system combining instrumentation, signal conversion and safety control.
The solution included:
- Installation of a safety relay system
- Integration with a universal signal converter
- An innovative pressure measurement configuration
Instead of using a conventional negative pressure sensor, we configured a differential pressure transducer in a creative way:
- The negative port of the transducer was connected to the pressure source
- The positive port was connected to the atmosphere
This configuration allowed the transducer to effectively measure the negative pressure differential relative to atmospheric pressure. The signal was then processed through the universal converter, enabling accurate interpretation of the pressure values.
Safety Integration and System Response
The system was programmed to continuously monitor pressure levels. When the pressure reaches the critical threshold of –70 Pa, the following safety sequence occurs:
1.The pressure signal is detected and converted by the universal converter.
2.The signal triggers the safety relay system.
3.The safety relay cuts power to Channel 1 immediately.
4.This action causes the butterfly valve to close automatically, preventing further pressure changes and protecting the system.
This rapid response ensures the system remains protected from potentially hazardous conditions.
Results and Impact
The solution delivered several key benefits:
- Reliable monitoring of extreme negative pressure conditions
- Immediate automated safety response
- Protection of system components from damage
- A practical engineering solution despite market equipment limitations
Most importantly, the system provides the client with confidence that critical pressure conditions are monitored and controlled safely.
This project demonstrates our ability to develop innovative, practical engineering solutions when standard equipment does not meet the application requirements. By combining instrumentation expertise with creative problem-solving, we delivered a robust safety system tailored to the client’s specific operational needs.
Contact Us
At Hale Engineering, we specialise in solving complex technical challenges while improving and future-proofing your systems. Contact us today to learn how we can support your operational needs.
Phone: +44 20 8154 6102
Email: info@hale-eng.co.uk