Dr C Narain

Spantech Products, South Godstone, Surrey, UK

The exclusive representative for ACD in Europe, Middle East and India

ACD History• Founded in 1988• Based in Tucson, AZ• Our goal is to research, develop and

manufacture dependable, accurate, reliable and affordable gas calibration standards.

• ACD have become experts and leaders in the calibration industry.

• ACD manufactures and distributes the most advanced hand held gas generators available to calibrate corrosive gas sensors

The ACD Family

ACD Product range

• The CAL2000

• The MiniCal

• The MiniBump

Benefits of ACD Products

• Instruments are small, light weight, durable and dependable.

• Gas is generated electrochemically as needed, not stored until used, so instruments do not degrade over time.

• Safe to ship, use, store and dispose of.

• Our instruments save the customer time and money

Current solutions for toxic calibration gases

Calibration gas cylinders• Unstable over even relatively short time• Leads to short shelf lives• Leads to uncertainty over actual

concentrations

Fixed concentrations

Bulky

One type of gas per cylinder

Current solutions for toxic calibration gases

Permeation tubes

• Highly temperature dependent.

• High power consumption.

• Cannot be turned on and off.

• Mainly for laboratory use.

Electrochemical gas production

Faraday’s law:

“The amount of chemical change during electrolysis is proportional to the charge passed”

Variable parameters

• Current supplied

Use an accurate and controllable current source with microprocessor control (for CAL2000)

• Amount of air blended with the gas generated in the cell

Miniature mass/flow controller• Maximise the reaction efficiency

What determines the reaction efficiency?

Electrolyte• Must be stable with time and replenishable

Electrodes• Must resist oxidation (or reduction)• Must be able to carry sufficient current.

Cell body• Must not leak• Should help to maintain stable cell environment• Must be mouldable.

Other issuesGas is produced in bubbles• We need to control the bubble size to

maintain a smooth and repeatable output.

Gas/electrolyte separation• The electrolyte must be separated from the

electrolyte prior to mixing in air, so that it will not escape into the electrolyte bulk.

We use a Teflon membrane to separate the air mixing chamber

The ACD solution

Advantages of Electrochemical Generation

• Can change concentration and flow rates by changing currents and mixing rates.

• A large amount of gas can be produced from a solid or gas.

• Can switch reaction on and off.• Cells will last for years (if designed properly).• Cells (and instruments) are small and compact.• Low power consumption.

Advantages of Electrochemical Generation

• Interchangeable cells.• Can be used in hazardous environments.• No temperature dependency.• Can use an inert balance gas.• Can monitor reaction voltages to check the

reaction efficiencies.

Disadvantages of Electrochemical Generation

• Limited number of gases.

• Pressure sensitivity.

• Can be expensive on short-term.

The CAL 2000

• Unmatched versatility and accuracy in corrosive calibration gases.

• Field replaceable electrochemical generating cells.

• Microprocessor controlled.

One instrument - many gases!

One instrument will generate:

• Chlorine• Chlorine Dioxide• Hydrogen• Hydrogen Cyanide• Hydrogen Sulphide• Bromine

The CAL 2000 is the most cost effective method of providing

calibration gases.

The CAL2000 provides 50X the amount of gas per £ vs cylinders

CAL2000 FeaturesEase of use• LCD Display• Field adjustable

PPM and flow rate• Hand held design• Low power

consumption• Micro processor

controlled operation

Safety features:

• Cells do not degrade over time.

• Automatic purge on shutdown

• Built in mass-flow sensor that compensates for altitude and temperature

• Suitable for both diffusion and sample drawn systems

Latest News!!• CSA certified

CAL2000 now available.

• All sensors factory calibrated to NIST standards

Coming soon:• Bromine• Ammonia

Specifications

Chlorine - 0.5 to 50ppm

Chlorine Dioxide - 0.5 to 5.0ppm

Hydrogen - 0.5-50ppm

Hydrogen Cyanide - 0.5 to 50ppm

Hydrogen Sulphide - 0.5 to 50ppm

Note: PPM is variable with flow rate,

output given at 0.5 Lpm.

Useful cell time: 50 hours

Warm up time (to 90%)

approx. 5 minutes

Weight: 3 Lbs

Accuracy: +/- 10%

Repeatability: +/-5%

Operating temperature: 0 to 50 °C

Battery life 25-30 hours

The MiniCal

• Low cost• Compact (pocket sized)• Cost effective

Gases generated :• Chlorine

• Hydrogen Sulphide

• Hydrogen Cyanide

• Hydrogen

MiniCal Specifications

• CSA NTRL/C Exia intrinsically safe

• Automatic purge on shutdown

• Alkaline battery powered

• disposable generating cell

• Cell life: 2 or 10 hours• Accuracy: +/- 10%• Repeatability: +/- 10%• Weight: 0.5 Lbs• Battery life: 4-6 hours• Warm up-time (to80%): 2

minutes• Operating temperature:

-30 to 50°C

How much less does it cost to use the MiniCal compared to cylinders?

• Each field replaceable cell costs about the same as a cylinder but gives 10X the gas output.

The MiniBump

• Ultra Small Gas Generator

• Designed to “bump” test sensors

• Each cell costs the same as a cylinder but will give up to 1000 bump tests

The ACD instrument range

Global Service for a global market

Customer comments

• We like your instrument and will recommend to all our customers as a reliable and easy operative source for generating Chlorine Dioxide and other gases"

• - Natasha Portman, Interscan Corporation”

• Thank you A.C.D., for setting a new standard in chlorine gas samples." - Terry Hebert, Dow Chemical, U.S.A.”

• The MiniCals are from Heaven" - Erkki Semi, Sarlin, Finland”

• We appreciate the personalised service" - Q.E.C., U.S.A.