Barton 199 Differential Pressure Unit
Functioning as actuating units for an extensive range of devices, BARTON 199 differential pressure units (DPUs) are each comprised of a bellows unit assembly (BUA) and removable pressure housings. Their supple bellows are attached to a centerplate within the BUA. Dual-bellows models’ flexible bellows are firmly attached by a dual valve stem running through the centerplate. Rupture-resistant bellows are featured in all models.
A seal with the valves is created by the valve seats, located in the centerplate passage, as a drive arm rotated on the end of a sealed torque tube reaches the valve stem in the centerplate. A noncorrosive, pure liquid with a low freezing point fills the bellows and resistance against enacted pressures is produced by a range spring assembly.
Pressure is enforced on both sides of the bellows during use. When changes in pressure occur, the bellows move until the force is balanced out by the spring effect (range springs). Proportional to the DP, the linear movement of the bellows is transferred through the torque tube as a rotary motion.
If the bellows within dual-bellows units experience a DP more powerful than the unit’s DP rating, a valve shuts and the fill liquid is thus held within the bellows. This helps avoid rupture and supports the bellows, offering complete protection in both directions due to the fact that opposing valves are employed.
For HzS service, the specially engineered BARTON 199N NACE DPU complies with NACE requirements. Functionality and attributes align with those of the regular M199 DPU, with the following exceptions:
- Capable of measuring DP up to 2000 psi (138 bar) while avoiding instrument damage caused by overpressure
- A 3-3/4″ diameter bellows is utilized for DP up to 15 psi (1 bar)
- A 2 1/8″ diameter bellows is utilized for DP above 15 psi (1 bar)