Gas Detectors with Sample Pumps - Should You Use Them?

Recently one of International Gas Detectors’ Directors was involved in a discussion on the Gas Detection professionals LinkedIn Group regarding a member’s concern for sample points and felt the comment required further explanation.

The issue was should one utilize detectors with sample pumps?

Basically, the answer to this question is no. Anything that stands between the detector and the risk introduces the possibility for unreliability and resultant detection errors. At International Gas Detectors, they aim to use diffusion based sensors directly into the area of concern. This is definitely the most reliable technique. In certain instances, this is not possible and at that point they choose to use sampling gas detectors.

IGD’s Concern

At present, IGD is developing six Gene Therapy Modules for a client. These are very sterile environments which are repeatedly fumigated. Standard diffusion based gas detectors could not be employed. The client was keen to minimize equipment in the modules to hinder the potential for bacterial traps. Extracting a sample for gas detection was the only answer.

Many sampling gas detection systems sequentially sample to a common detector. On systems with numerous detection points this method can result in long cycle times. For instance, a system with 10 sample points and a two-minute sample time at each point, then the cycle time is 20 minutes meaning 9 out of 10 ports will not be sampled for 20 minutes.

The Solution

IGD produce both addressable sample pumps and addressable four-port samplers. This solves the issue of long cycle times. If the application is important then use a point sampler where the pump/detector is dedicated to only one sample point. In less significant applications, a four-way addressable sampler only ever has a maximum of 4 ports to sample around, limiting dead time.

Furthermore, IGD’s Piezo pump technology has almost no moving parts. Many sampling systems have an array of pumps, valves, filters, etc as part of their make up all with related seals and wear parts. IGD’s samplers employ piezo pump technology, no seals, valves, wear parts or diaphragms to maintain. IGD’s samplers are practically maintenance free and self-monitoring.

The samplers used by IGD extract their sample via IGD’s unique gas sample port. This is fitted through the wall reducing the impact within the clean room. The sample port is available with a luer fitting allowing basic anti-bacterial filters to be fitted in regular operation. Furthermore, this allows the ports to be ‘capped off’ during fumigation.

In this case, IGD placed all sampler modules local to the sample points. Sixty samplers were fitted and all were networked using IGD’s Sentinel+ addressable highway technology. Each sampler has local flow monitoring, very short sample lines and the capability to self-zero or in the case of oxygen detection, self-calibrate.

Conclusion

The system has reduced cost compared to sequential samplers.

One of the major wins for the client; the system has minimal cost compared to sequential samplers, and using IGD’s novel Piezo samplers there will be no need for solenoid, conventional sample pump and moving parts with equipment providing more than a five-year lifetime.

This information has been sourced, reviewed and adapted from materials provided by International Gas Detectors Ltd.

For more information on this source, please visit International Gas Detectors Ltd.