|
ABBITZ™ Measurement, Inc.
|
|
OVERVIEW ABBITZ™ Model 310 differential pressure unit (DPU) is a mechanical device which accurately measures differential pressure relative to a gas or liquid flowing through a process system, or the liquid level contained in a process vessel,
AVAILABLE MODELS Actuators:
310 DPU Actuated Units:
113C DPU Actuated Units:
WHEN ORDERING Please Specify Quantity Model Number Housing Pressure Rating (SWP) Housing Material Bellows Material Process being measured Differential Pressure Range Type of Scale Scale Graduations Mounting type
|
|
Differential Pressure Instrumentation |
|
Return HOME |
|
ABBITZ Model 310 DPU VS. Barton® Model 199 DPU |
|
Barton® is a registered trademark of Cameron International Corporation (Cameron®) |
|
Model 310
ABBITZ™ Differential Pressure Unit (DPU) serves as an actuating unit for a wide variety of instruments. Featuring ABBITZ’s™ new edge welded rupture-proof bellows. Also functions as a drop-in replacement for Barton’s® M199 DPU.
Description Each DPU consists of a Bellows Unit Assembly (BUA) and removable pressure housings. Within the BUA, flexible bellows are secured to a centerplate. In dual-bellows models, the movable bellows are rigidly connected by a dual valve stem that passes through the centerplate. Valve seats, in the centerplate passage, form a seal with the valves. Contacting the valve stem in the centerplate is a drive arm pivoted on the end of a sealed torque tube. The bellows is filled with a clean, noncorrosive, low-freezing point liquid. A range spring assembly provides tension against applied pressures. In operation, pressure is applied to both sides of the bellows. Any difference in pressure causes the bellows to move until the spring effect (range springs) balances out the force. The linear motion of the bellows (proportional to the DP) is transmitted as a rotary motion through the torque tube. In dual-bellows units, if the bellows are subjected to a DP greater than the unit’s DP rating, a valve closes and “traps” the fill liquid in the bellows — fully supporting the bellows and preventing rupture. Since opposing valves are used, full protection is provided in either direction.
Common Components · Bellows Construction: Individual diaphragms, stamped and formed from 316L Stainless Steel and are assembled using highly specialized tools and techniques, edge welded using GTAW technology, the results– 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 need for lubrication. The stems ruby bearing and the roller ball bearing on follower drive arm, operate with a minimum of friction – resulting in high sensitivity over the life of the unit. · The torque tube assembly consists of a tube, shaft, ruby bearing, head and tail pieces. The outboard end of the torque tube is attached to the centerplate via the gland nut. The shaft passes through the center of the tube and is welded to the tail piece. Since the head piece is attached to the centerplate, the tube must twist when subjected to torque. The shaft, freely supported at its outer end by the ruby bearing, and attached to the tube and the tail piece at its inner end, rotates through the same degree of angle as the drive arm – the mechanical output of the DPU. · The torque tube assembly consists of a tube, shaft, ruby bearing, head and tail pieces. The outboard end of the torque tube is attached to the centerplate via the gland nut. The shaft passes through the center of the tube and is welded to the tail piece. Since the head piece is attached to the centerplate, the tube must twist when subjected to torque. The shaft, freely supported at its outer end by the ruby bearing, and attached to the tube and the tail piece at its inner end, rotates through the same degree of angle as the drive arm – the mechanical output of the DPU. · Range springs: Determine the DP range of the unit, based upon their combined spring rate. They have extremely low hysteresis and exceptional temperature stability. The model 310 has an external range spring assembly that is field replaceable.
Dual Rupture Proof Bellows The 310 is designed to measure differential pressures under the most severe operating conditions. The unit incorporates ABBITZ’s™ new GTAW edge welded rupture-proof bellows. Ease of installation, stable calibration, and minimal maintenance are qualities built into the 310 DPU. The 310 is composed of a Bellows Unit Assembly (BUA) and a pair of pressure housings that enclose opposite sides of the BUA. The BUA consists of a pair of bellows, centerplate, valve stem, over range valves, temperature compensating floating convolutions, torque tube assembly, dampener valve, and range spring assembly.
· Temperature Compensator: An additional free-floating bellows, attached to the HP bellows, automatically protects unit from zero/calibration drift caused by ambient temperature changes. · Pulsation Dampener: Internal dampening is accomplished by restricting the flow of liquid through its normal channel (the annular passage in the centerplate) and causing it to follow an alternate route controlled by an adjustable needle valve. Response time for the unit depends upon the range and fill liquid, but is typically adjustable between a few seconds and several minutes for full scale travel of the bellows.
Performance Specifications Torque Tube Rotation (full scale DP)……………………………8°±10% Torque Tube Material……………………….316 Stainless Steel Temperature Limit……………………………..-40°F/°C to +180°F (+82°C) Maximum Non-Linearity: 0-10”w.c. to 0-400”w.c.(0-25 mbar to 0-993 mbar) ….±0.5% of full scale with appropriate linkage Repeatability………………………………0.20% of full scale DP |
