ITT Barton Model 226, 226A & 226C

 The Barton® Model 226C is the current version of this particular 3" differential pressure indicator. The Barton 226C and the legacy versions are designed to measure liquid flow or liquid level. In flow measurement applications, the instrument is connected to a primary device's low- and high-pressure sides in the process run. The primary device may be any pressure drop device, such as an orifice plate, venturi tube, or flow tube. In liquid level measurement applications, the instrument is connected to monitor changes in hydrostatic pressure caused by variations in liquid height in a vessel.

The ITT Barton model 226 Differential Pressure Indicator consists of two major components: an actuating Differential Pressure Unit (DPU) and the case-enclosed indicating instrument (indicator). The indicator has a 3 inch dial. The indicating pointer traverses a 270°arc (nominal) to measure differential pressure, flow or liquid level. The indicator movement has a micrometer screw for range adjustment. Zero is adjusted by "slipping" pointer on hub, which can be done without removing the scale plate or the pointer. The range can also be adjusted without removing the scale plate or pointer. Linearity adjustments are accessible after removal of the scale plate. The ITT Barton model 226 is actuated by an ITT Barton model 224 DPU.

 The bellows within the DPU move in response to changes in the differential pressure measured at the primary device installed in the process system. This movement of the bellows is mechanically transferred to the indicator mechanism, which in turn positions the indicating pointer.

The indicator is attached directly to the actuating unit (DPU). The indicator consists of a drive arm assembly, linkage, and a movement assembly to which the indicating pointer is attached. Changes in differential pressure are sensed by the DPU bellows and transmitted as rotary motion through the torque tube to the drive arm assembly of the indicator. The linkage and movement assembly responds to the drive arm assembly's action to position the scale pointer to the indication relative to the differential pressure sensed by the DPU.

Housings and Safe Working Pressures

Forged Brass (FG Brass)......................SWP 500 PSI (34.5 bar)

Brass ....................................................SWP 1000 PSI (68.9 bar)

Carbon Steel ........................................SWP 1500, 3000, & 6000 PSI (103.4, 206.9 & 413.8 bar)

316 Stainless Steel...............................SWP 500,1500, 3000, & 6000 PSI (34.5, 103.4, 206.9 & 413.8                                                                  bar)

Cast Aluminum ....................................SWP 400 PSI (27.6 bar)

Allow Steel ............................................SWP 10,000 PSI (689.5 bar)

Bellows Material

316 Stainless Steel

Beryllium Copper 

Inconel 625

DP Ranges

0-30" W.C to 0-1000 PSI (ranges limited by the SWP and housing materials chosen.)

Actuating Unit.......................................Model 224 DPU

Dial Size...............................................3 Inches (75mm) Diameter

Temperature Limits.............................-40°F/C to + 180°F (+82°C) (+40°F minimum for water filled units- "D" Fill)

Adjustments........................................ Zero and Span (Micrometer-type)

Mounting..............................................Flush/Panel, Wall, and 2"Pipe/Yoke, 

Indicator Case.....................................Aluminum Alloy, Powder Coated, Enamel or Epoxy Finish

Lens.....................................................Polycarbonate

O-Rings (Wetted).................................Buna-N, Viton, or EPT (Special available upon request)

Overall Dimensions.............................per configuration and DPU housing rating 

Weight.................................................6 to 9.5 lbs (approx.) Weight depends on DPU                                                                configuration/materials.

Accuracy (DP Range)

0-30 IN WC to 0-50 IN WC

(0-75 mbar to 0-124 mbar).........................................±0.75% of full scale

0-51 IN WC to 0-60 psi

(0-127 mbar to 0-4.1 bar).......................................... ±0.5% of full scale

0-61 psi to 0-150 psi

(0-4.2 bar to 0-10.3 bar) ........................................... ±0.75% of full scale

0-151 psi to 0-400 psi

(0-10.4 bar to 0-27.6 bar)...........................................±1.0% of full scale

Bellows Construction - Individual diaphragms, stamped and formed from 316 stainless steel, Inconel 625, or beryllium copper, are assembled using highly specialized techniques. The results are exacting linearity characteristics, a long cycle life, and freedom from effects of work hardening commonly encountered with the hydraulically formed or mechanically rolled type bellows. 

Torque Tube eliminates the possibility of leakage and the need for lubrication. The needle bearing (inboard end) and ball bearing (on follower drive arm) operate with a minimum of friction, resulting in a high degree of sensitivity over the unit's life. 

Temperature Compensator—An auxiliary free-floating bellows attached to the HP bellows automatically protects the unit from zero/calibration drift when the ambient temperature changes.  

The self-draining/Venting Connection on the top and bottom of the pressure housing provides automatic liquid draining or venting of gases.

Calibration Springs—The strength of the range springs determines the differential pressure range of the unit. Each range spring assembly is stamped with the DP range it produces. Range springs have an extremely low hysteresis characteristic and exceptional temperature stability.