METER TUBE WITH SEGMENTAL ORIFICE PLATE
Meter tube is a complete set consisting of segmental orifice plate and straight lengths of piping on its inlet and outlet. Design of the meter tube is divided into three parts: inlet, in which fluid flow is straightened, measuring part (orifice plate) and outlet.
Straight lengths of piping of the meter tube comply with all conditions of dimensional and geometric accuracy defined by ISO 5167 standard that are related to the pipe sections adjacent to the orifice plate. This layout guarantees inlet of stabilized fluid flow into the primary element and accurate measurement of the flow rate. Conception of meter tubes also minimizes nonconformities during assembly of orifice plates and their subsequent operation. Division of meter tubes into individual sections also enables easier maintenance inspection or subsequent verification of the meter.
There are individual differential pressure tapping. These are incorporated in the body of flanges, between which the plate is placed, centred and sealed. The pressure tapping is led out of the flanges. Upon agreement with the customers outlets of differential pressure are always customized to various options of primary element attachment to the metering circuit. The meter tube set consists of stainless steel distance bolts that greatly facilitate dismantling and subsequent assembly of the disc.
Meter tube with segmental orifice plate is manufactured in nominal diameters DN 50 up to DN 1,400. Meter tube with segmental orifice plate is manufactured in basic version with straight lengths of piping 5D “downstream” the orifice plate and 2D “upstream” it or, in sub-version with straight lengths 2D “downstream” the orifice plate and 2D “upstream” it.
2D section “downstream” the orifice plate is je ended by a flange and it can be supplied with a counter-flange including connecting materials (fasteners) and sealing. 2D section “upstream” of the orifice plate is ended with preparation to weld. Ending of section 2D “upstream” the orifice plate can be flanged upon agreement with customers. Meter tube in partial version can be equipped with the verified section 3D supplementing inlet section “downstream” the orifice plate to total length 5D. 3D section for the attachment to the piping is ended by preparation for weld.
For the production of the meter tube there is mostly used carbon steel or stainless steel. Its disc is made of stainless steel as a standard.
The meter tube with segmental orifice plate is manufactured either as a working meter or, as a specified meter with metrological verification complying with the technical particulars and conditions of pattern approval.
Segmental orifice plate has the advantage of high accuracy of measurement comparable to the centric orifice plate as well as min. straight pipe lengths “upstream” and “downstream” the plate. Its considerable advantage is its full flow capacity. The flow cross-section has a shape of a circular segment enabling entrainment of fixed deposits as well as oil and tar fumes draining at the point of measurement.
Upon agreement the meter tubes with segmental orifice plates can be manufactured with extended straight lengths of piping and where appropriate, with DN different than stated above. Meter tube with segmental orifice plate can be incorporated both in horizontal or oblique piping.