What is the Average Usage Life of the Non-Evaporative Getter (NEG) Pump for a HAPSITE ER?

Applies to: Chromatography Hapsite ER (GC/MS) | Tickets Solved: 0

HAPSITE ER: Average Usage of the NEG Pump

The NEG Pump allows the HAPSITE ER to be portable. Bench top Mass Specs use turbo and roughing pumps to provide a vacuum, however the NEG pump uses a chemical reaction to create the needed vacuum. As the NEG pump is used, by-products of the chemical reaction build up in the pump and begin to decrease its ability to provide an adequate vacuum. The time in which this build up occurs can vary based on several items:

1. Usage of the instrument. NEG pumps that have routine PMCS’ are able to function for longer periods of time than those that are used regularly. The HAPSITE ER has the extended standby mode that also keeps the NEG heated to operating temperature. This was created by the OEM to prevent buildup of contaminants while the NEG was cool.
2. The type and concentration of chemicals run through the instrument. Certain chemicals can task the Mass Spec and result in the pump becoming damaged. This can also occur if high concentrations are run through the instrument.
3. The length of time for initial installation. NEG pumps that are not allowed adequate activation time will have a shorter life span than those are activated for the recommended time.
4. Leaks in the Mass Spec. Leaks can occur in Mass Spec and when introduced in the HAPSITE ER, can lead to contaminants that interfere with the chemical reaction of the NEG pump.

During installation of the NEG pump, operators should complete a leak check. In the field, a NEG pump has been seen to have an average life of between 100-140 hours. The OEM has NEG pumps with over 500 hours on them. Overall, the following list can be used to determine if your NEG pump has reached the end of its functional life.

1. Is the MS pressure above 6*10^-3. This is the upper limit of the operating pressure for the HAPSITE ER. Operators should begin to track pressure once it reaches 3*10^-3.
2. Incorrect Temperature readings. Operators who have NEGs that read the incorrect temperature should contact technical support. Technical support will be able to isolate the issue and determine if it is NEG related. Common incorrect temperature readings are 1.5 or 498.5.
3. Ion Pump Failures. The Ion pump reads the MS pressure created by the NEG pump. The Ion Pump itself rarely goes bad and its failures are related to a NEG pump being unable to create an adequate vacuum. The NEG pump replacement cost is significant and replacing it necessitates a 24 hours non-functional period for the instrument.

Operators should use the above lists and technical support to help determine the life of the NEG pump.

Contributed by

Was this helpful? Yes No

Keywords: NEG, Life