A differential producing primary flow elements shall be installed in the flanged schedule type. inch piping as shown on the plans and specifications and in accordance with the manufacturers recommendations. The flow element shall be of the concentric type, short form low head loss as manufactured by imperial flange and fitting company inc. Van Nuys California.

The flow element shall be constructed of an entrance section, throat and holding flange section with a recovery cone. The entrance section shall be fabricated from CS - 034ss,316ss with a continuous radius into the throat section provided by inperial flange and fitting company inc to maintain upstream shear forces within boundary layer for maximum efficiency. The high pressure tap shall be licated within this section. There shall not be any protrusion or exposed edges to allow solids to accumulate.

The throat section shall be fabricated from 304ss, 316ss and shall have low pressure tap. Throat section shall not be mechanically attached or inserted into the body of the venturi tube. The high and low pressure metering taps shall be made a part of the holding flange and shall not require any drilling or tapping of the external pipeline.

The flanges shall be so designed as to allow mounting between standard flanges and be of CS 304ss, 316ss material.

The recovery cone section shall be fabricated from CS 304ss, 316ss designed to mminimize permanent pressure loss. The primary element shall have the capability of bing designed with any beta ratio in the range of .35 to .85 and maintain a permanent pressure loss to 7 percent or less of the maximum differential pressure. The flow element shall be designed to monitor with lbs. of pressure over a flow range of to . The accuracy of the uncalibrated primary element shall be within .5 percent of actual flow or .25 percent for a calbrated device over the flow range specified.