Ametek CO Monitor

The basic operating principle of the detector is based upon the strong absorption of UV light by mercury vapor. Compounds eluting through the RGD-equipped analyzer pass through a heated mercuric oxide bed. In this bed, the reducing compounds in the sample (i.e. compounds that can combine with oxygen) react with the mercuric oxide thereby releasing mercury vapor. This vapor is then measured by a photometric cell as a change in the absorption of UV light. The change in absorption is directly proportional to the concentration of the reducing compound within the sample gas.

The instrument should be calibrated using a known concentration of CO in air (as close as possible to the target concentration). There is some non-linearity with the instrument response and thus a correction will be applied by the IS at the data workup stage. For a user supplied calibration cylinder, we would offer to check this against a NOAA supplied calibration cylinder (which is the WMO GAW standard).

Consumables

• The TA3000 CO analyser requires a supply of compressed air, N₂ or He as a carrier gas. #These must be dry and free of CO (a CO trap can be provided).
• One 50 litre, 200 bar cylinder lasts for around 2 months of continuous operation.
• The instrument requires calibration with a standard cylinder of CO in air.
• It is best to use a concentration close to those you expect to be measuring.
• A CO calibration cylinder with regulator can be provided on request. The instrument will also measure H2 but the user would have to provide their own calibration cylinder for this.
• The instrument uses an HgO bed for the detection. These last for about 500 hours of operation and cost £1500 to replace so a contribution to this cost would be required.

Costs

• Instrument Insurance
  • This system must be insured by the user for £50K and covers loss, theft or damage to the instrument: damage is that over and above general wear and tear. The system has been designed to be rugged and autonomous. Even so, the end-user must respect the fact that the system is a precision optical instrument that must be treated with great care.
  • The user is responsible for the instrument from the time it leaves the AMOF to the time it is returned and signed off as in an acceptable operating condition by the IS: this will be done as soon as is possible on its return.
• Public Liability Insurance
  • The AMOF is not liable for any damage or injury arising from the deployment or operation of this instrument when unattended by the IS.
• Shipping Expenses
  • The user is liable for all costs arising from the shipping of the instrument both to and from a deployment.
• IS T&S
  • The user is responsible for coving the travel and subsistence expenses of the IS while attending the instrument.

Shipping

The system when packed ready for shipping consists of a single flight case

• Shipping dimensions:
  • 80 cm (L) x 60 cm (D) x 40 cm (H)
• Shipping weight:
  • 50 kg
  • This does not include the carrier gas and calibration standard cylinders.

Instrument requires an indoor space (ideally air conditioned) to operate.

Instrumental Hazards

• All the instruments are self-enclosed so many of the potential hazards from the instruments are reduced

Changing of cylinders

• All experimental work must stop on the instrument while changing the cylinder.
• Safety glasses must be worn whenever any work is undertaken on a high-pressure system.
• The correct pressure regulator must be used with the correct type of cylinder.

Handling and moving of cylinders

• Cylinder trolley must be used for moving any cylinder.
• Safety glasses must be worn whenever opening a regulator for the first time.
• A training course must be completed

Electrical Hazards

• All instruments must be powered down before any maintenance can be performed.
• All electrical devices must be checked and certified.
• Operators must have knowledge of the location of exposed electrical connections.
• Ensure instruments are earthed at all times.

When unpacked the instrument has the following physical specification

• Foot print:
  • 60 cm (L) x 55 cm (W) x 35 cm (H)
• Weight (not including shipping case):
  • 25 kg
• Power:
  • 300W @ 230
• Operation temperature:
  • 10°C to 30°C

The data product would be a time series of CO mixing ratio (and H2 if a calibration standard is provided). The data cycle is 210 seconds, with the sample being representative of the 60 seconds previous to the time stamp.

Field Data

• The instrument produces a range of out files and all are text format.
• The user can download (but not delete) this data from the instrument but it should be noted that this data will not have been quality controlled.

Archive Data

• Data is provided in NetCDF files following the AMOF data standard
• Files contain no more than 24hr of data.
• Instrument name is
  • ncas-co-1,
  • ncas-co-2
• The data product(s) associated with this instrument:
  • co-concentration
• Example data file
  • How to use example data
  • ncas-co-1_ral_29001225_co-concentration_v0.1.nc
  • ncas-co-2_ral_29001225_co-concentration_v0.1.nc