Model 116
Bellows Type
Tank Level Gauge
±1% Full Scale Accuracy | Optional Micro-Switch | Bi-Directional Over-Pressure Protection
The Mid-West® Instrument Model 116 is a high-accuracy differential pressure gauge designed for closed-tank liquid level monitoring across a broader range of ΔP values. Using a bellows sensing element and mechanical linkage, the Model 116 delivers direct, sensitive, and reliable pressure readings with ±1% full-scale accuracy.
The gauge consists of a two-piece brass body, bellows sensor with over-pressure protection, torque tube mechanism, range spring, and 6-inch dial. The pointer includes a micro-adjust feature that allows for re-zeroing in the field if needed.
Optional micro-switch functionality is available: a mechanically driven cam linked to the bellows can actuate one or two fast-acting micro-switches for use in alarm, control, or feedback applications.
To protect internal components, the Model 116 includes a bi-directional Over-Pressure Relief Valve (OPV) that activates when differential pressure exceeds 130% of the rated range, equalizing pressure between the high and low sides.
Key Features:
- Bellows-type sensing element with mechanical linkage
- Optional integrated micro-switches for control or alarm output
- Micro-adjust pointer for easy field re-zeroing
- Bi-directional over-pressure protection (130% of range)
- ¼” FNPT dual top and bottom process connections
- Brass body with 316 stainless steel internals
- Viton® seals standard (others available upon request)
- 6” dial face: white-on-black standard; black-on-white optional
- Temperature range: -40°F to 200°F
- Proof pressure: 2x working pressure at ambient temperature
Ideal for tank-level applications involving cryogenic or liquefied gases, the Model 116 can be customized with dial scales for specific media and tank geometries.
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Product Features/Benefits
- Rugged Bellows Sensing Element
- Glass Reinforced Thermoplastic Dial case (Panel Mountable)
- Weather Resistant & Corrosion Resistant Gauge Front
- 270° Dial Arc
- Shatter Resistant Lens
- Over-Range Protection, High over Low and Low over High
- 1 Year Warranty
- For complete model details See Bulletin_115_116.pdf
- Installation and Operation Manual See Bulletin: IOM_116.pdf
Specifications / Configuration
- Dial Sizes available: 6” Diameters
- Dial Scale Ranges: 0-70” H2O to 0-800” H2O
- Differential Full Scale Ascending Accuracy available: ±1% (ASME B40.1 Grade 1A)
- Available in a Variety of Dial Scales: LOX, Ar, O2, N2, LBS. CO2, CM H2O, MM H2O, KGS, LNG, etc.
- Working Pressures 500 PSIG (34 Bar) 1000 PSI optional (69 Bar)
- Operating Temp -40°F to +200°F (-40°C to +93°C)
- Weather Protection & Corrosion Resistant
- Material of Construction of Body - Brass (Wetted Part)
- Internal wetted parts-316 Stainless Steel
- Dual Top and Bottom Process connections
- Brass Snubber fittings mounted in bottom process connections
- Optional O-rings Materials: Buna-N, Viton, and Ethylene Propylene.
- For complete specifications see: Specificationsheet_115_116.pdf
Common Applications
- Pressurized Tank Level Monitoring
- Stationary Tanks – Horizontal or Vertical
- Tanker Transport / Over the road trailers For materials such as LOX, CO2, Ammonia, Nitrogen Helium, Nitrogen, Hydrogen and Argon
Micro-Switch Specifications: (Available on 6” Dial Only)
Model 116 can be configured with one or two independently adjustable SPDT micro-switches. Each switch can be set to actuate on rising or falling differential pressure, allowing for reliable control, alarm, or system feedback functions.
Minimum differential pressure range for switch operation: 80” H₂O.
Switch adjustments are made using accessible screws after removal of the lens and bezel (secured by 4 front screws). Each switch is mechanically driven by a cam linked to the bellows—no external power is required for actuation.
Electrical Interface:
- Color-coded 18 AWG flying leads
- ½” FNPT conduit connection
Switch Ratings:
- 1 or 2 independently adjustable SPDT switches
- 5 A @ 120 VAC
- 3 A @ 240 VAC
- 4 A @ 30 VDC
- Adjustable actuation from 3% to 95% of full scale (decreasing pressure)
- CSA Listed as Industrial Control Equipment
See Installation and Operation Manual : IM116DPIS 6” DIAL ONLY
Additional Options:
- ¾” FNPT Stainless Steel Stub Mount Bracket
- Pipe Mounting Kit - 2" U-Bolt
- Multiple 3-Valve Manifold Options
- Oxygen Cleaning
- CRN – Canadian Registration Number
The Mid-West Advantage
- 1 year warranty
- 30 + Years Hazardous Location product manufacturer.
- OEM and Private Label Capabilities
- Fast on-time Deliveries
- Friendly Customer Support
- Certified Quality System CSA B51-09 SAI GLOBAL
Tank Level , Diaphragm Type
| Model No. | Differential Pressure Range | Accuracy | Working Pressure | Electrical Available | Specifications | Installation/ Operation Manual | Electrical IOM | Drawing |
|---|---|---|---|---|---|---|---|---|
| Model 114 | 0-0.72 PSID (0-20" H20) to 0-20 PSID (0-600" H2O) Tank Level Applications |
±3/2/3% | 1000 PSI | CE / LVD, RoHS Compliant, NEMA 4X, 4-20mA Transmitter |
Tank Level , Bellows Type
| Model No. | Differential Pressure Range | Accuracy | Working Pressure | Electrical Available | Specifications | Installation/ Operation Manual | Electrical IOM | Drawing |
|---|---|---|---|---|---|---|---|---|
| Model 115 | 0-10" H2O to 0-69.9" H2O Tank Level Applications |
±1% | 500 PSI (Optional 1,000 PSI) | None available | N/A | |||
| Model 116 | 0-70" H2O to 0-800" H2O Tank Level Applications |
±1% | 500 PSI (Optional 1,000 PSI) | MICRO SWITCHES 0-80" H2O to 0-800" H2O NEMA 4X, CSA LISTED IND. CONT. EQUIP. |
