Masoneilan 12810 Pneumatic Proportional-Reset Level Controller
Overview
The Masoneilan 12810 is the proportional-reset member of the Baker Hughes 12800 Series of pneumatic level controllers. Like the rest of the family it senses level with a displacer hanging from a torque tube and turns the movement into a 3-15 psi or 6-30 psi air signal that positions a control valve without electrical power. What sets the Masoneilan 12810 apart is reset action: it keeps correcting a level offset until the level returns exactly to the set point, instead of leaving the steady-state error that a purely proportional controller can leave behind.
Seven Star LLC supplies the Masoneilan 12810 to refineries, gas plants and process facilities in Oman and the GCC where pneumatic loops still run on separators, accumulators and vessel bottoms. Our Muscat team asks for the nameplate, liquid specific gravity, displacer range and valve action before confirming the model.
Operating Principle of the Masoneilan 12810
A level change alters the buoyant force on the displacer and rotates the torque tube. A reversing arc and control link move a control arm, which positions a flapper against a nozzle, and a relay amplifies the nozzle pressure so that about 3.5 psi at the nozzle gives the full 12 psi change of a 3-15 psi output. Up to here the mechanism is that of a proportional controller.
In the Masoneilan 12810 the bellows spring of the proportional unit is replaced by a reset bellows, and a resistance unit and capacity tank sit in the air circuit between the two bellows. After a deviation the proportional bellows reacts at once while the reset bellows follows more slowly through the resistance. Air flows until the pressures in the two bellows are equal, and equilibrium returns only when the level is back at its set point, so the reset rate is adjusted by changing the resistance.
Choosing Reset Action for the Masoneilan 12810
The proportional band scale shows the percentage of the total level range through which the level must travel to move the output from 3 to 15 psi. Baker Hughes advises setting the band as narrow as the process allows without cycling, because that keeps level variation to a minimum. Where the band cannot be narrowed enough to hold the level within its limits, the manual says reset should be added, which is the case the Masoneilan 12810 is built for. The reset rate knob counts repeats per minute, meaning how many times each minute the reset action repeats the effect of the proportional action for a given deviation.
Engineering Design of the Masoneilan 12810
The two parts that distinguish the 12810 from the proportional 12800 are the resistance unit assembly and the reset bellows tubing. The resistance unit may need occasional cleaning: the manual has the technician back the reset knob off, withdraw the unit body from the frame with a twisting motion, strip the spring retainer, spring, button, plug and O-ring, blow out the ports and wipe the parts with a lint-free cloth. On reassembly the reset knob is turned back to the 0.02 mark.
Alignment and Tuning of the Masoneilan 12810
Alignment follows the proportional procedure after one extra step: with the displacer hanging free, the reset rate index is set at 6 (open) and the control setting index is adjusted for 9 psi output. When 9 psi has held for at least 30 seconds, the index is moved to the white dot, which locks 9 psi in the reset bellows.
For tuning, start with a low reset rate, around 0.02 to 0.2 repeats per minute, and narrow the proportional band as far as the process allows without cycling. Widen the band by about 50 percent, then turn the reset knob slowly clockwise until cycling occurs and set the reset rate to roughly half that value.
Converting a Proportional 12800 to the Masoneilan 12810
The 12800 Series is designed for field conversion between modes using a kit of the parts involved: a bellows tubing assembly, a reset bellows assembly and a resistance unit assembly. The manual has the technician remove the output pressure gauge, disconnect the bellows tubing, move the proportional band index fully left and compress the bellows spring until its button clears the proportional spring thread. The reset bellows slides into the spring’s place, the resistance unit is mounted in the lower left corner of the case and new tubing is fitted with the copper gasket supplied. The gauge is then refitted and the mechanism aligned.
Key Features
- Reset action returns the level to the set point after a disturbance, removing offset.
- The reset rate knob is graduated in repeats per minute.
- The proportional band scale shows the percentage of level range needed to move the output from 3 to 15 psi.
- The control link and reversing arc select direct or reverse action and compensate for specific gravity down to 0.1.
- The Masoneilan 12810 runs on instrument air alone, with no wiring at the controller.
Industrial Applications
Reset action is chosen when a narrow proportional band alone would make the loop cycle or when the process cannot tolerate a permanent offset. The Masoneilan 12810 therefore suits level loops with changing inflow, such as separators and accumulators in oil and gas, refining and petrochemical service at Sohar, Duqm and Salalah. The same torque tube hardware supports interface service between two liquids.
Typical loop partners are the Masoneilan 10000 series double-port control valve and the Masoneilan Type 87/88 spring-diaphragm actuators.
Related published Masoneilan pages: Masoneilan 35002 Series Camflex rotary control valve.
Technical Specifications
Published data for the Masoneilan 12810 from the 12800 Series instruction manual (Baker Hughes, 2022).
| Parameter | Specification |
|---|---|
| Model | Masoneilan 12810 proportional-reset level controller |
| Control mode | Proportional plus reset (integral) action |
| Output signal | 3-15 psi or 6-30 psi |
| Supply and regulator | Filter regulator fed with 50 to 125 psi gauge; set to 20 psi for 3-15 psi output, 35 psi for 6-30 psi |
| Reset adjustment | Knob in repeats per minute; resistance unit and capacity tank between the bellows |
| Reset alignment | 9 psi locked in the reset bellows with the index at the white dot |
| Typical starting reset rate | 0.02 to 0.2 repeats per minute |
| Case limit | Ambient at the case not above 180 degF; 1/4 in. NPT supply and output |
| Service life | 25 years or more with annual inspection |
Related Masoneilan level instruments include the Masoneilan 12800 Series pneumatic level controller, Masoneilan 12400 Series digital level transmitter, Masoneilan 12820 pneumatic level transmitter, Masoneilan 12830 differential-gap level controller and Masoneilan 12840 pneumatic-set level controller.
Request a Quote for Masoneilan 12810
Send a formal RFQ for the Masoneilan 12810 to the Seven Star LLC instrumentation division with the displacer range, mounting arrangement, specific gravity, output range and control action. We confirm the model, advise on availability and lead time and supply the Baker Hughes instruction manual from this page. In Oman and the GCC, Seven Star LLC delivers genuine products with manufacturer documentation and local engineering support.
- Instruction Manual Masoneilan 12810 Level Controller Instruction Manual Download
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The globe valve listing centers on the 21000 series, including the cryogenic version with extension bonnet, and the 41005 cage-guided series in high pressure, API 6A and VRT anti-cavitation executions. The 80385 and 80386 are three-way combining and diverting valves. Rotary products include the 35002 Camflex II and the 37002 MiniTork II butterfly control valve. Actuators cover spring-diaphragm, cylinder and rack-and-pinion designs, among them the 5A cylinder actuator for Camflex II. Masoneilan also makes pressure regulators, SVI digital valve positioners and displacer-type level instruments, and offers Lo-dB trim for noise control.Where Masoneilan valves are used
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For spare parts the serial number is decisive, since the factory record behind it lists trim, materials and actuator. Send a clear nameplate photo with serial number, model number, size and pressure class. For a new valve add the process data: fluid, inlet and outlet pressure, temperature, minimum, normal and maximum flow, required leakage class, fail position, air supply and control signal.Browse Masoneilan products by category: Control Valves, Valve Actuator, Regulators, Valve Positioner, Level Transmitter.
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