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Dual Chamber Orifice Fitting

With input from engineering firms, measurement specialists and field personnel, TMCO has strengthened the advantages of orifice metering by implementing features that improve the performance of your meter runs, simplify your operations, reduce maintenance costs and keep your people safe in the field.

The SureShot® Dual Chamber is TMCO’s flagship fitting. Customer-driven design features ensure safe, cost-effective, and operationally excellent solutions to the most demanding gas measurement challenges.


SureShot® Dual Chamber Orifice fittings fully conform to the latest AGA 3/API 14.3 stringent requirements. They require no added uncertainty and provide accurate performance over the orifice plate beta ratio range from 0.1 to 0.75 within 0.5% flow accuracy to theoretical value.

Design Features

  • Eccentric Isolating Plug Valve
  • Removable End Caps
  • SureLock™ Safety Device and Lockout/Tagout
  • Orifice Plate Carrier
  • Single-Piece, Precision Machined
  • Metal-to-Metal Seat
  • 4-Point Alignment System

Isolating Eccentric Plug Valve Assembly &
Removable End Caps

This patented differentiator ensures overall Lower Cost of Ownership – fewer parts, easier and cleaner maintenance routines, heightened operator safety, less uncertainty of measurement.

  • Greaseless design … delivers clean, positive isolation between upper and lower chambers
  • Teflon seal and stainless steel retainer … ensures optimal sealing with minimum drag across seat of plug valve minimizing maintenance over the life of the fitting
  • Two-handed open/close Standard Operating Procedure … helps prevent accidental opening while the upper chamber is under pressure
  • Elimination of grease, springs, and slide valve … simplifies operations and lowers maintenance costs
  • Removable end caps … enable inspection and/or replacement of the plug valve sub-assembly without removing the upper chamber
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Safety Device and SureLock™
Lock Out/Tag Out

Key safety features of the TMCO fitting keep operators safe in the field:

  • Spring-loaded design locks the Eccentric Plug into the closed position, preventing accidental engagement while the upper chamber is open
  • Lock Out/Tag Out (LOTO) option prevents tampering or operation of fitting without first unlocking the SureLock device to actuate the Eccentric Plug
  • For additional safety, Eccentric Plug will not close if the plate carrier is improperly positioned, forcing operator attention and proper placement of the carrier

Orifice Plate Carrier

Accuracy features of the TMCO orifice plate carrier increase revenues and eliminate revenue
loss by providing secured and repeatable plate positioning and reduced seal ring

  • Precision Machined Carrier
    Design allows for secured plate positioning, eliminating downstream movement of the orifice plate during high differential pressure
  • Four Point Alignment System
    Factory-set internal screws, located at the bottom and sides of the fitting’s internal body, and a ball plunger located in the top of the plate carrier, ensure accurate and repeatable positioning and concentricity
  • Metal To Metal Seat
    Metal-to-metal seat against the downstream face significantly reduces seal ring compression and downward shift of orifice plate
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Orifice-Plate-Carrier1 Orifice-Plate-Carrier2

SureShot® Dual Chamber Specification List

  • 2, 3, 4, 6, 8, 10, 12, 16
  • ANSI Class 150 (285 PSI CWP)
  • ANSI Class 300 (740 PSI CWP)
  • ANSI Class 600 (1480 PSI CWP)
  • ANSI Class 900 ( 2160 PSI CWP) (3” only)
  • A-216 WCB/WCC
  • Consult factory for options
  • -20°F to 275°F (-29°C to 120°C)

  • ANSI Class 150 to ANSI Class 600 inclusive
  • Weld x Flange; Flange x Flange; Raised Face, Ring Type Joint (RTJ)
  • AGA 3/API 14.3, ISO-5167
  • ANSI B31.3, ANSI B16.5; MS SP-55
  • NACE MR-01-75-2000
  • Hydrostatic test 1-1/2 times rated CWP.
  • Tested for positive plate seal, pressure tap integrity, seal protrusion and eccentricity

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