Vacuum Systems for Mobile Analysis

Field-Use Mass Spectrometers and Leak Detectors

Today's applications increasingly require analytical systems that are easy to transport and suitable for mobile use. For example, mobile gas analysis, mass spectrometry and leak detection are used in investigating pollution caused by road and air traffic, analyzing water quality, detecting explosives and toxic substances at airports, as well as in mobile analysis of respiratory gases. Mobile analysis presents serious challenges in terms of the vacuum equipment used. Support pumps together with high-vacuum pumps and mass spectrometers must be small and lightweight. Furthermore, their power consumption must be very low and they must operate reliably even in the presence of slight vibrations.

Mobile Mass Spectrometer System with Pfeiffer Vacuum Solutions on a Vehicle

Scientists under the direction of Dr. Verbeck at the University of North Texas in America developed a mobile mass spectrometer system mounted in the trunk of a hybrid car. This device was used, for example, directly at the site to investigate the adverse environmental effects of hydraulic fracturing areas. The key features of this mobile system are shown below

All vacuum components must operate on 24V DC. Criteria for selecting the best possible equipment:

• Light weight, • Small installation area, • Low power requirement during extended battery operation, • Vacuum equipment unaffected by vibration.

Portable Mass Spectrometer Systems

Pfeiffer Vacuum developed a prototype vacuum system for use with mass spectrometer systems in a pilot project. This system, mounted on a supporting frame, can be easily carried like a backpack thanks to its weight of only 9 kilograms. It operates on a 24V DC lithium-ion battery. Thus the system can be used independently. A HiPace 10-type turbo pump with a 10 l/s pumping speed and a two-stage MVP 003-2 diaphragm pump with a 0.1 m³/h pumping speed made this system's lightweight design possible. The system is also equipped with a cold-cathode high-vacuum gauge and a piezo/Pirani rough-vacuum gauge for vacuum measurements. An analyzer can be mounted in the vacuum chamber.

Applications of Mobile Analyzer Systems

• Investigating the environmental effects of road and air traffic, • Pollution analysis, • Personal protection following accidents at chemical and petrochemical facilities, • Detection of explosive atmospheres at hazardous facilities, • Water analysis, • Mobile geochronological dating (for example in glaciers), • Local determination of emission values for early warning of volcanic eruptions, • Location of underwater volcanoes using CO2 detectors from submarines, • Determining the environmental effects of hydraulic fracturing, • Oil and gas analysis during drilling and processing, • Monitoring climate change due to global warming, • Detection of explosives and toxic substances at airports or on aircraft during baggage control and similar operations, • Police applications such as examining smoke traces, • Military applications such as detection of toxic gases during warfare, • Detection of illegal drugs during road checks by motor vehicles or officials, • Mobile analysis of respiratory gases, • On-site detection of facility and vacuum system leaks.

Mobile Mass Spectrometer System for Volcanic Emission Measurement

In seismic measurements, accurate verification data from the actual site that would enable more precise prediction of future volcanic eruptions is generally lacking. Accurate predictions that would support rapid response measures to protect people and air traffic from severe ash emissions are only possible when this data is available. Such measures can seriously prevent loss of life and property. In a joint project between the University of Costa Rica and NASA Ames Research Center, USA, with JPL (NASA), INGV Vesuvius Observatory, Inficon Inc. USA/Germany, Creare Inc., USA, on-site measurement equipment was developed to monitor and analyze gases in volcanic plumes.

This system can be used to perform the following measurements:

• Gases such as SO2, H2S, CO2, helium, CH4, • Temperature, pressure and humidity, • GPS coordinates and altitude, • Emitted particles, • Ash samples for analyzing effects on air traffic (aerosol particles). Plume column areas above the volcano are monitored. To enable measurements, the system is used together with an unmanned aerial vehicle flying over this area of the volcano. In addition to measuring volcanic emissions, these systems have also been used for various analytical purposes; • Detection of toxic BTEX substances (benzene, toluene, ethylbenzene, xylene) in oil and gas extraction areas and processing facilities, • Environmental analyses over the semi-Antarctic continent (Chile), • Analyses over volcanoes in Italy, Costa Rica and Hawaii, • Detection of illegal drugs.

Portable Helium Leak Detectors

Mobile and portable leak detectors are required for a wide variety of applications such as determining leaks during vacuum system assembly or service operations. Both mobile and stationary leak detection provide accurate and reliable results, especially when helium is used as the tracer gas.

There are two basic operating modes for helium leak detectors:

• The vacuum method, in which the system is partially or completely evacuated and the tracer gas helium is applied from outside, • The sniffer method, in which the test sample is filled with tracer gas at excessive pressure of Δp> 100 hPa. Escaped helium tracer gas is drawn into the leak detector via a sniffer valve and detected. Both methods can be reviewed in Table 2 with regard to operating principle and detection limits. Detectors with a total weight not exceeding approximately 25 kilograms are classified as mobile or portable. They can be transported on a vehicle and passed through baggage control on airline flights. Pfeiffer Vacuum's product range includes mobile leak detector systems for a wide variety of applications. MiniTest is used only in the vacuum leak method. Without a support pump, this model is extremely lightweight.

The benefits it provides are as follows;

• Durable, reliable, easy and low-maintenance, • Vacuum leak detection with quartz window sensor to locate and pinpoint even the smallest leak, • Compact dimensions and light weight–ideal for service calls, • Leak detection down to 5-10-7 hPa l/s at 1 l/s pumping speed is possible, • High water vapor tolerance, • Inlet pressure up to 200 hPa abs, • External compact flange connection option, • Low maintenance costs.     Sabine Neubrand Trylat Product Manager Pfeiffer Vacuum GmbH         İbrahim Bağış General Manager An-ka Analiz & Kalite Kontrol Cihazları Ltd. Şti.