Instruction Manual

760007-A July 2003

Model NGA2000 PMD

2-3 LOCATION

Install the Analyzer Module in a clean, non- hazardous, weather protected, vibration free location free from extreme temperature varia- tions. For best results, either install the module near the sample stream to minimize sample transport time or supply a flow greater than necessary and route only the appropriate amount through the Analyzer Module.

An oxygen-free gas, typically nitrogen, is required for use as the zero standard gas. Recommendations for span calibration gases, bases on various operating ranges, are tabulated in Table 3-4 on page 3-10. Air (20.93% oxygen) can be used as span gas regardless of the ranges used for sampling, although very low ranges may lose accuracy.

Sample Gas

Observing these requirements are critical. Note the following:

•Excessive vibration can cause a noisy readout. To minimize vibration effects, the detector/magnet assembly is envel- oped in a shock-mounted compartment.

•The user should ensure, when making any internal electrical connections, that no cables are placed in contact with the detector assembly or associated internal sample inlet and outlet tubing.

•Magnetic susceptibilities and partial pressures of gases vary with tempera- ture. Permissible ambient temperature range is 32°F to 113°F (0°C to 45°C).

•The interior of the Detector Assembly is maintained at approximately 144°F (62°C) by an electronically controlled heater. Prior to entering the detector assembly, the sample is heated in a coiled tubing to match the detector's temperature.

2-4 GASES

a.Requirements

Calibration Gases

Analyzer Module calibration requires the establishment of zero and span calibra- tion points. This requires a zero standard gas to set the zero point span gas to es- tablish a calibration point at or near the upper range limit.

Sample gas should be non-flammable.

Temperature

Sample temperature at the inlet should be from 50°F to 150°F (10°C to 66°C). A maximum entry temperature of 110°F

(43°C) is recommended to prevent cooling of the sample and possible internal condensation. Such condensation could damage some components of the Analyzer Module. This recommendation can be ignored if a thoroughly dry sample is examined.

Pressure

Sample exhaust pressure limits are -5 to 10 psig (-345 to 690 hPa-gauge). Normal operation is in the positive range, between 0 and 10 psig (0 and 690 hPa- gauge). Negative gauge pressures are not normally recommended, but may be used in certain special applications.

To prevent over-pressurization, insert a pressure relief valve into the sample inlet line. A check valve should also be placed in the outlet line if the Analyzer Module is connected to a manifold associated with a flare or other apparatus that does not operate at atmospheric pressure.

The outlet port is commonly vented to the atmosphere. Any change in barometric pressure has a directly proportional effect on the indicated percent of oxygen, and should be neutralized through manual or computer correction of data. Note the following example:

2-2 Installation

Rosemount Analytical Inc. A Division of Emerson Process Management