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Liquid Tank Level Measurement

Diaphragm and Bellows type instruments can be used as liquid tank level indicators. As shown in the image, The high pressure port connects to a tap at the bottom of a tank. The low port then connects to the atmosphere.

How To Measure The Liquid Tank Level

A differential pressure instrument can be used to measure liquid level as a function of head.

The user will specify the desired units (mm., inches of water, lbs., CO2, etc.).  To measure the correct level in open tanks, the instrument should be mounted at the bottom of the tank.

If the tanks are closed or pressurized, the low pressure port can be connected to the top of the tank as shown in the figure. Regardless of the pressure, the liquid inside will give similar head as open tanks and the instrument will indicate the precise level.

More Information

Watch this video by RealPars for a visual demonstration and Find a distributor to get the right instrument you need for liquid tank level measurement.

Liquid tank level

Recommended Models:

Model No. Differential Pressure Range Accuracy Working Pressure Electrical Available Specifications Installation/ Operation Manual Electrical IOM Drawing
Model 105 0-10" H2O (0-0.4 PSID) to 0-79.9" H2O (0-2.9 PSID) ±1/2% or 1%
Note:
1/2% Full Scale available 30" H2O & above		 Up to 6,000 PSI LOCKED LOGIC SWITCHES
NEMA 4X, Class I Division I, GROUP. B, C & D, Class II Division I, GROUP. E, F & G
Model 106 0-80" H2O (0-3 PSID) to 0-800" H2O (0-30 PSID) ±1/2 or ±1% Up to 6,000 PSI LOCKED LOGIC SWITCHES
NEMA 4X, Class I Division I, GROUP. B, C & D, Class II Division I, GROUP. E, F & G
MICRO SWITCHES
0-80" H2O to 0-800" H2O, CSA LISTED IND. CONT. EQUIP.
Model 109 0-15 PSID to 0-6000 PSID (Dependent on Body Material and Safe working Pressure) 1/2% or 1% Full Scale
(1/2% Not available above 1,000 PSID or Bi-Directional Ranges)
NOTE:
Bi-Directional Accuracy is 1% Total Span
±3% Total Span
(For Ranges above 1,500-0-1,500 PSID) 		Up to 6,000 PSI LOCKED LOGIC SWITCHES
Weather-proof Housing, NEMA 4X, Class I Division I, GROUP. B, C & D, Class II Division I, GROUP. E, F & G
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.
Model 114 0-0.72 PSID (0-20" H20) to 0-20 PSID (0-600" H2O)
Tank Level Applications		 ±2% 1000 PSI CE / LVD, RoHS Compliant, NEMA 4X, 4-20mA Transmitter
Model 142 0-20" H2O to 0-25 PSID ±3/2/3% Up to 3,000 PSI CE / LVD, RoHS Compliant, NEMA 4X, Terminal Strip, Class 1-Div. 2, 4-20mA Transmitter
Model 140 0-50" H2O to 0-100 PSID 0-50" H2O to 0-399" H2O
±5%
0-15 PSID to 0-100 PSID
±3/2/3%		 Up to 3,000 PSI CE / LVD, RoHS Compliant, NEMA 4X, Terminal Strip, Class 1-Div. 1, Class 1-Div. 2, 4-20mA Transmitter
Model 700 / 710 / 715 0-5 PSID to 0-300 PSID ±0.50% 2,900 PSI 2-Wire
4-20 mA Transmitter 15-28 VDC, LCD = 4-20 mA Transmitter 18-28 VDC, LED = 4-20 mA Transmitter 20-28 VDC
3 Wire
15-28 VDC/1-5 VDC, 15-28 VDC/0-5 VDC, 15-28 VDC/0-10 mADC, 15-28 VDC/0-20 mADC, 15-28 VDC/0-10 VDC 		N/A