Liquefied Gas Injector for Karl Fischer Moisture Meters

Accurate measurement of moisture in liquefied gases is essential for quality control and operational safety. Moisture in liquefied petroleum gases (LPG) such as propane, butane, and dimethyl ether (DME) must be analysed to meet product specifications and control corrosion of transfer lines. Measuring moisture in refrigerant gases is important to assure proper operation of air conditioners and other similar devices.

The common way to measure these gases was to collect the sample in a cylinder, connect a needle, and place the tip of the needle into the Karl Fischer titration cell. The cylinder valve would have to be opened slowly and carefully so that the sample will bubble calmly in the KF solution. If the valve was opened too quickly, there was risk that cell will become over pressurised and stoppers or electrodes would pop.

Mitsubishi Chemical Analytech’s VG-200, liquefied gas injector for Karl Fischer moisture meters, solves all of the issues of the conventional method. The sampling cylinder simply needs to be connected to the VG-200 without any needles. After the desired injection volume or weight is set, the unit will automatically inject the designated amount. The heater inside the unit will ensure that all of the sample will be vaporised and guided into the KF titration cell. After moisture is titrated in the KF cell, the results are calculated by the instrument. So in summary, by just setting injection volume and gas type, the correct amount of moisture in the liquefied gas sample can be determined automatically.

By using the VG-200 with one of Mitsubishi’s moisture meter models such as CA-200 or CA-31, replicate measurements up to 9 times from the same cylinder can be run automatically unattended. The VG-200 can also be used as a stand alone unit so it can be used with any moisture meter in the market. With only 15cm in width, this highly practical unit can be added with minimal bench space.