The PrevEx is Control Instruments’ analyzer for lower flammable limit-range (% LFL/LEL) monitoring. It demonstrates tremendous accuracy, speed of response, consistency and reliability in a wide range of tough industrial process applications and industries. It performs critical safety functions, protecting plant and personnel, while also providing the ability to increase productivity and profitability through process-control energy savings.

Proprietary technology

A carefully metered pilot flame burns continuously inside a small explosion-proof chamber of the sensor housing. Flammable vapors and combustible gases are drawn through the sample tube by means of an air aspirator, where they are incinerated by the flame. A temperature detector measures the resulting change in the flame temperature and transmits the information for display in % LFL format. The sample gases are then exhausted back to the process.

Figure 1: A carefully metered pilot flame burns continuously inside a small explosion-proof chamber of the sensor housing. Source: Control Instruments

Unmatched safety

Figure 2: Relays include warning, danger, fault, service needed and system under calibration. Source: Control Instruments

The PrevEx’s advanced self-diagnostics and fail-safe features include a malfunction relay that when automatically tripped notifies the operator immediately of a status change, such as loss of fuel, air, sample flow or power. Relays include warning, danger, fault, service needed and system under calibration. By contrast, many types of “indirect” measuring systems can register as normal even when not properly working.

Universal calibration

The PrevEx gives consistent and reliable readings even when measuring multiple or changing solvent concentrations. Importantly, there is no need for recalibration when changing process recipes; the sensing-flame technology provides accuracy across an extremely broad range of process chemistry, improving process efficiency.

Figure 3: The PrevEx. Source: Control Instruments

Agency approvals

The PrevEx Flammability Analyzer has received Factory Mutual, ATEX, IECEx, UKEX, Factory Mutual Canada and NEPSI approvals, as well as SIL certification for safety integrity.

Rugged and reliable

Designed with the stresses of the most difficult industrial installations in mind, the PrevEx Flammability Analyzer isn’t a sensor made for area monitoring in a room or lab forced into a process application. It is a sturdy build for a long life in industrial applications. Even in the highest temperature applications, the PrevEx will operate safely and provide the longest life of any LFL analyzer in the industry.

Direct mount design

Figure 4: The PrevEx has a heated, corrosion resistant sample train, which eliminates potential clogging due to condensation within the analyzer. Source: Control Instruments

Durable industrial design allows for direct mounting of the PrevEx to an oven/dryer wall or exhaust duct. This assures the fastest possible response time as there is no need for long sample tubing to the analyzer, which also eliminates any possible condensation issues with the sample. The PrevEx has a heated, corrosion resistant sample train, which eliminates potential clogging due to condensation within the analyzer. The result is a very fast, accurate reading and reduced maintenance.

Efficient operation

The front panel of the PrevEx includes a complete set of status indicators and an LCD display. Using just two push buttons, users can access all calibration, programming and diagnostic routines.

· It is equipped with solenoid valves for both zero and span test gas; an integral microprocessor automatically makes all calibration adjustments for users.

· It can be accessed remotely through an optional multi-channel operator interface or PLC via digital communication through a Modbus RS-485 serial port, as well as two 4-20 mA analog outputs.

· Four inputs are also provided for customized control functions.

Tailored to customer requirements

The PrevEx Flammability Analyzer consists of several models designed to fit specific monitoring needs, including the most demanding conditions of industrial monitoring, where high temperatures, high flash-point solvents, water vapor, resins and plasticizers may be present, or the oxygen concentration limited. There are options for indoor or outdoor installations.

Find out more today

The PrevEx’s exclusive design is a direct measure of flammability and has been proven to be the most reliable detection system in the industry, with over a billion hours of safe operation worldwide.

Control Instruments Corporation has been engineering solutions to gas and solvent vapor monitoring problems since 1969. They work hard to assess risks and carefully tailor a monitoring system to meet customer needs. For detailed information, system specifications and pricing, contact them today.