Integral Orifice Flow Meter

An integral orifice flow meter ships as one factory-mated assembly: the orifice primary element, the DP transmitter, the 3-valve manifold, and the short impulse tubing arrive on a single packing slip, already piped together and already zero/span calibrated on the factory wet-flow loop. A bare orifice plate, by contrast, ships as a passive primary element only; the buyer specifies and procures a separate Rosemount 3051, Yokogawa EJA, or Honeywell ST3000 DP transmitter, runs the impulse lines on site, mounts the manifold, and performs field zero-cal during commissioning. The integral build trades transmitter flexibility for single-PO sourcing, faster commissioning, and one warranty point of contact. It is the right choice for a plant that does not already operate a DP-transmitter parts shelf and does not employ a trained DP-transmitter calibration technician on staff.

Probably not. If you already operate a Rosemount 3051, Yokogawa EJA, or Honeywell ST3000 base across the plant, your maintenance team carries spare transmitters, calibration carts, and trained technicians who can field-zero a DP transmitter in 20 minutes. In that case the bare-primary route is the better fit: buy the orifice plate, nozzle, venturi, or annubar element on its own and pair it with a transmitter from your existing parts shelf. The cross-link is the orifice plate flow meter model on the differential-pressure hub. The integral build exists for buyers who do NOT have that infrastructure: small-bore process-gas users, OEM skid builders specifying for a packaged unit, and mid-size plants where adding one DP loop does not justify standing up a Rosemount asset base.

The integral version typically saves 1500 to 3000 US dollars on the transmitter line item compared with sourcing a premium Rosemount 3051 plus 3-valve manifold separately, and it removes roughly four to eight hours of field commissioning work per loop (impulse-line bleed, manifold tuning, transmitter-to-primary span match, first-zero-cal). The trade-off is transmitter flexibility: you cannot drop in your preferred Rosemount or Yokogawa head later without re-piping the manifold, and the factory-paired transmitter is a 4-20 mA HART loop with RS-485 Modbus optional only, not a fieldbus node. If a specific fieldbus protocol is part of the spec, go to the bare-primary orifice plate option and bring your own head.

The factory K-factor and ISO 5167 / GB/T 2624 wet-cal are valid for the fluid, density, and temperature you specified on the order. If you change service later, for example moving the loop from instrument air to natural gas, or from water to a glycol-water mix, the discharge coefficient and the expansion factor change, and the flow reading drifts unless you re-size. The good news is that the primary element is mechanical and unchanged. You send the operating P, T, and fluid composition to engineering; we return the corrected square-root parameters and either reprogram the transmitter HART configuration or ship a replacement orifice plate at the right beta ratio. The transmitter itself does not need to come back to the factory; it is reprogrammable in the field over HART.

Lead time is 5–7 business days from the factory. The assembly ships with the orifice primary element, the factory-paired DP transmitter mounted on the element, a 3-valve manifold (5-valve manifold optional), short impulse tubing, isolation valves, the factory ISO 5167 / GB/T 2624 wet-flow calibration certificate, the ISO 9001 quality cert, a mill cert traceable to the heat number for the wetted-metal element, and the CNEX Ex d IIC T6 Gb cert sheet if the hazardous-area transmitter housing was ordered. EMC 2014/30/EU Annex II compliance ships standard with each transmitter. The factory holds the ISO 5167 / GB/T 2624 wet-cal cert and the ISO 9001 quality cert only; other custody, sanitary, or EU-directive cert packages are not shipped from this factory and should not be specified on the PO.