Flowmeter assembly

Before taking the sample train to the test site, it is wise to prepare the operating curves for the particular job. With most factory-assembled trains, these curves are a part of the package. If a sampling train is assembled from components, the curves must be developed. The type of curves will vary from source to source and from train to train. Examples of useful operating curves include (1) velocity versus velocity pressure at various temperatures (6), (2) probe tip velocity versus flowmeter readings at various temperatures, and (3) flowmeter calibration curves of flow versus pressure drop. It is much easier to take an operaHng point from a previously prepared curve than to take out a calculator and pad to make the calculahons at the... 

Gas inlet/exit assembly glass two-hole stopper with glass inlet and exit tubes Hydrogen flowmeter Filter paper... 

The oscillation amplitude is too small (typically, 100 pm) to cause damage to the meter. Because the excitation current is also very small, intrinsically safe CMF versions are available for use in hazardous areas. The electronics can be mounted on the flowmeter directly, forming one compact unit, or the flowmeter can be interfaced to the electronics via a cable. The remote assembly may be necessary for high-temperature meters, or it may be convenient if the sensor is installed in a place that is not easily accessible. 

Impeller and shunt flowmeters are widely used in steam and gas flow metering. They comprise an orifice plate in the main flow line and a self-operating rotor assembly in the bypass. As gas flows through the meter body, a portion of the flow is diverted to drive the fan shaft assembly. The rotational speed of the shaft is proportional to the rate of flow at all rates within the normal range of the meter. 

Apparatus is assembled so that dry nitrogen flowing at a rate of about 8 1. per hour through a calibrated flowmeter (made with l-mm. capillary tubing as the orifice) passes through the sulfur trioxide in its flask at about 25° and thence into the reactor. A stream of fluorine also enters... 

The equipment shown is an air-cooled plugging indicator in the process of assembly. The flowmeter, inlets, outlets, and cooling jacket are apparent. The wire wrapping is heating cable to provide preheating of the unit and to prevent premature precipitation of the oxides. 

Fig. 2. Multichannel assembly of toxicity test units, (a) Components included an electronic timer (A), liquid flowmeters (B), mixing chambers used for insoluble (C) and soluble (D) toxicants peristaltic pump (E), and exposure chambers (F). Syringe pumps were mounted outside the environmental room to avoid effects of low temperature and high humidity on operation, (b) View of magnetic stirrers (F) situated beneath the drainboard used to support exposure chambers (E). (c) A bank of 10 exposure chambers housed in a 6 ft x 10 ft environmental room. Inlet lines from mixing chambers (A) were attached with rapid disconnects (black arrow). The watertight drainboard (B) contained spillage. Test chamber outlet lines (white arrow) were connected to waste receptacles (C). (Copyright ASTM, 1916 Race Street, Philadelphia, PA 19103. Reprinted with permission.)...

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