ITT Barton Model 289

 These 6" differential pressure-indicating switches energize alarm and control circuits at predetermined limits of flow through pipelines, liquid levels within pressurized vessels, or pressure losses across devices such as filters. They are used in conjunction with a primary DP element, such as an orifice or venturi, to monitor flow rates.

The weatherproof ITT Barton­® Model 289 is an analog DP indicating switch. The Model 289 has a NEMA-4 watertight die-cast aluminum case (finished with a weather-resistant black epoxy resin paint or powder-coated). The durable Lexan lens is secured in the bezel with an elastomer ring to reduce the possibility of accidental breakage. This ring also acts as a seal between the bezel and the case to ensure a moisture-free, fume- and dust-free atmosphere for the jeweled indicator movement and switch mechanism.

  The die-cast aluminum indicating switch housing is attached directly to the actuating unit (199 DPU). The indicating switch assembly consists of a drive arm with an integral switch actuator cam, linkage, and a jeweled movement assembly to which the indicating pointer is attached. Also included are the high and low micro switches and associated linkages, switch set point indexes, and set point locks. Changes in differential pressure are sensed by the differential pressure unit's bellows and transmitted as rotary motion through the torque tube to the drive arm assembly of the indicating switch. 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 199 DPU. It simultaneously actuates the switch when the desired setpoint is reached. It does this because the drive arm has an integral switch actuating cam and is attached to the torque tube shaft, which rotates between 8 and 10 degrees with the motion of the torque tube shaft. Two cam follower roller/actuator arm assemblies, one for each switch, respond to drive arm movement by opening and closing the switches as they ride on and off the cam. The levels of differential pressure at which the switches actuate are adjustable with high and low alarm switch adjustment indexes below the scale plate.
Minor adjustments to the switch set point can be made without removing the scale plate. The ITT Barton Model 289 can have up to four alarm switches, but one or two alarm switches are standard. Each switch can be connected to operate normally open or normally closed. The switch set points are adjustable between 5% and 95% of the scale range. SPDT and DPDT switch configurations are available. The ITT Barton Model 289 includes pulsation dampening through an integrated needle valve located on the center block.

 Housings and Safe Working Pressures

Forged Steel.........................................SWP 2500, 4500, & 6000 PSI (172, 310 & 413.8 bar)

316 Stainless Steel...............................SWP 1000, 3000, & 6000 PSI (69, 206.9 & 413.8                                                                  bar)

Bellows Material

316 Stainless Steel 

Inconel 625

DP Ranges

0-10" W.C to 0-100 PSID

Actuating Unit.......................................Model 199 DPU

Dial Size.................................................6 Inches (150mm) Diameter

Temperature Limits.............................-40°F/C to + 180°F (+80°C), +35°F  to 180°F (+1°C to +80°C)      ................................................................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 ..................................................Approx. 30 to 45 lbs (approx.) Weight depends on DPU                                                                  configuration/materials.

Iindication Accuracy 

SPDT

Ranges 0-10" to 0-349".......................................±1% of full scale (0-25 mbar to 867 mbar)

Ranges 0-350" to 0-100 PSI................................±1.25% of full scale (0-869 mbar to 0-6.9 bar)

DPDT

Add 1% to SPDT values

Point of switch actuation add 1/2% to SPDT values

Switch

Accuracy of;

Switch Repeatability...........................................±0.25% of full scale 

Switches Deadband...........................................±5% (SPDT), 6% (DPDT)

Switch type..........................................................Mechanical, Snap Acting

Contact type........................................................Single Pole, Double Throw (SPDT)

                                                                                Double Pole, Double Throw (DPDT)

Switch Rating

125 VAC.................................................................5 Amps (note 1)

250 VAC.................................................................2.5 Amps (note 1)

30 VDC Inductive..................................................1.0 Amps (note 2)

30 VDC Resistive...................................................3.0 Amps

125 VDC Inductive................................................0.2 Amps (note 1,2)

125 VDC Resistive.................................................0.4 Amps (note 1)

Relay

Coil Power Requirement

       DC Relay.........................................................1.5 Watts

       AC Relay.........................................................2.75 Volt Amps

Contact Types.......................................................SPDT, DPDT

Contact Rating .....................................................15 Amps at 115 VAC (note 1)

Note 1: Non-CE use only. Voltage limited to less than 50 VDC or 35 VAC for CE applications.

Note 2: Are suppression recommended for inductive loads.

Bellows Construction—Individual diaphragms, stamped and formed from 316 stainless steel or Inconel 625, are assembled using resistance welding techniques. The results are exacting linearity characteristics, a long cycle life, and freedom from the 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 minimal friction, resulting in high sensitivity over the unit's life. 

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

Pulsation Dampening—Pulsation dampening is adjustable via a needle valve on the center block's rear.

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.