Valve provides minimised dead volume, preventing the loss of liquid hydrocarbon components as is typical with conventional cylinder valve connections
Hale Hamilton and NPL (National Physical Laboratory) launch the MDV (minimised dead volume) ultra high purity cylinder valve and connector.
Conventional cylinder valve connections within ultra high purity applications introduce a number of technical disadvantages to the user and hence the process accuracy is jeopardised, says Hale Hamilton.
Typically, dead volumes within the standard connectors and valve outlets result in the loss of unknown quantities of liquid components during the preparation of hydrocarbon mixtures, resulting in errors in the calculated mole fractions of components.
In addition, dead volumes increase the overall surface area of the sampling system and therefore the potential for adsorption.
Polymer sealing washers used within conventional connectors further increase the potential for adsorption, out gassing of hydrocarbons and ingress of oxygen and moisture from the atmosphere.
The MDV valve provides minimised dead volume, preventing the loss of liquid hydrocarbon components.
The reduced surface area improves; sampling, speed of stabilisation and accuracy.
A metal to metal seal ensures there is no outgassing as is seen with conventional polymer washers; therefore a reduction in atmospheric contamination is achieved. Flexibility with the cylinder valve range is enhanced, as the MDV valve is also interchangeable with standard connections, where the application does not demand the high levels of accuracy achieved by the MDV valve.
