Product Review – The Gascoseeker Mk1

A Homage to One of the Greats

No gas detector review section would be complete without first looking at the marvellous GMI Gascoseeker MK1. Designed and developed by the old British Gas research team more the 35 years ago, the MK1 Gascoseeker is the benchmark for all other modern flammable gas instruments out there.

We suggest – if you want to get into gas measurement in the oil and gas industry, you get hold of one of these and become familiar with its workings.

Why? – Well the Mk1 has a two pellistor set combustion chamber allowing measurement of flammables in the LEL range and % volume. Each is selected manually, with the catalytic pellister being used for the LEL range and the thermal conductivity sensors used for the % volume.

The configuration allows for:

  • Leak tracing in the 0 – 10 %LEL range
  • Flammable measurements in the 0 – 100% LEL range and
  • High concentration flammable measurements in the 0 – 100 %volume range

The hand aspirated sample system draws the sampled has through a combustion chamber fitted with the 2 sensors producing a vary rapid response time. The sensors themselves have extremely long life times, with some lasting in excess of 30 years.

The Mk1 Gascoseeker was replaced by the Mk2 in the early 90’s. The same basic principles still applied, except the ranges were self selecting and auto ranging, the display was now digital and the pump electric and internal. For more – see the full review of the GMI Mk2 Gascoseeker.

The greatness of the MK1 gascoseeker is encapsulated by 8 simple principles:

  1. Physical strength  and robustness
  2. Simplicity of use
  3. The abigulity circuit, which locked the display full scale if high concentrations were being measured in the % LEL range. (For more see the @gt purging modules)
  4. Manual selection of measuring ranges and sensors  (LEL catalytic or % volume thermal conductivity)
  5. Speed of response
  6. Sensor stability and reliability
  7. Intrinsic safety
  8. Price.

Who knows, in the future, maybe one of the large modern manufacturers will learn from the past and produce a product as good and iconic as the MK1 Gascoseeker. GMI still produce modernised versions of the gascoseeker, but in this writers opinion, they don’t match up when compared to the 8 basic principles listed above.

And there is a lesson for all of us in the principles behind the MK1 design. If you are trying to decide which gas detector to buy, write a simple 8 point list and compare each device and score them accordingly. I’m sure you’ll quickly find what’s right for you. (For more see choosing the right gas detector)

Today we are still able get hold of MK1 Gascoseekers that work, but these are not recommended for practical use anymore as they do not conform to the current ATEX legislation. If you would however like one for training or personal use, get in touch and we will see what we can do.

The Editor @gt

Arobase Gas Testing






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