Operation
Total pressure cells are formed from two circular plates of stainless steel. The edges of the plates are welded together to form a sealed cavity, which is filled with fluid. Then a pressure transducer is attached to the cell. The cell is installed with its sensitive surface in direct contact with the soil. The total pressure acting on that surface is transmitted to the fluid inside the cell and measured by the pressure transducer.
Installation
Total pressure cells are embedded in fill or mounted on structures. In fill, cells are often installed in arrays. Each cell is placed in a different orientation and covered with hand-compacted fill. On structures, the cell is typically placed into a recess so that its sensitive side is flush with the surface of the structure.
Advantages
Conformance: To minimize bridging effects, the total pressure cell has a low profile and a modulus similar to that of a typical soil. Fluid in the cell is de-aired to maximize sensitivity.
Pneumatic or Vibrating Wire: The total pressure cell is available in a pneumatic or vibrating wire version.
Manual or Automatic Readout: The vibrating wire version can be read manually with a portable indicator or automatically with a data logger. The pneumatic version must be read manually.
For more information
Please download the datasheet and the manual for Total Pressure Cells. You can view and print these documents with Adobe Acrobat Reader.
Total Pressure Cells Specifications
| VW PRESSURE CELLS |
|---|
| 3.5 bar (50 psi) Pressure Cell | 52608220 |
| 7 bar (100 psi) Pressure Cell | 52608230 |
| 17 bar (250 psi) Pressure Cell | 52608240 |
| 35 bar (500 psi) Pressure Cell | 52608250 |
| Resolution | 0.025% FS |
| Repeatability | ±0.5% FS |
| Max. Pressure | 150% rated range |
| Fluid | Ethylene glycol, de-aired to 2 ppm |
| Dimensions | Cell is 230 mm diameter and 11 mm thick (9 x 0.43"). Transducer and connecting tube is 410 mm (16") long. Dimension from sensitive surface to connector end of transducer is 180 mm (7") |
| Weight | 3.2 kg (7 lb) |
| VW Jackout Cells |
|---|
| 7 bar (100 psi) Jack-Out Cell | 52618230 |
| 17 bar (250 psi) Jack-Out Cell | 52618240 |
| 35 bar (500 psi) Jack-Out Cell | 52618250 |
| SIGNAL CABLE |
|---|
| Polyvinyl Chloride (PVC) Cable | 50613824 | Shielded cable with four 22-gauge tinned copper conductors and polyvinyl chloride (PVC) jacket. Attached to pressure transducer at factory |
| Universal Terminal Box | 57711600 | Not used if pressure cells are connected to data logger. Provides connections for 12 sensors and an indicator. Sensors selected by rotary switch. Weatherproof fiberglass box measures 290 x 345 x 135 mm (11.5 x 13.5 x 5.25") |
| VW READOUTS |
|---|
| Compatible readouts include the VW Data Recorder and other pluck-type VW readouts. See separate data sheets for details. |
| DATA LOGGERS |
|---|
| VW MiniLogger for 1 Sensor | 52613310 |
| 4-Channel V-Logger | 52615140 |
| 8-Channel V-Logger | 52615180 |
| Campbell Scientific Data Loggers | VW pressure transducers connect directly to the VW MiniLogger, V-Logger and Campbell Scientific CR6. Campbell Scientific CR800 or CR1000 require an AVW200 vibrating wire adapter. See separate data sheets. |
| PNEUMATIC PRESSURE CELLS |
|---|
| 21 bar (300 psi) Pressure Cell | 51408200 | Pressure cell has pneumatic pressure transducer attached. Requires pneumatic tubing |
| 21bar (300psi) Jackout Cell | 51418200 |
| Range, Resolution and Repeatability | Determined by pressure gauge and indicator |
| Fluid | Ethylene glycol, de-aired to 2 ppm |
| Dimensions | 230 mm diameter x 11mm (9 x 0.43"). Transducer adds 300 mm (11.75"). Jackout version has transducer is mounted to center of cell. From sensitive surface to connector end of transducer measures approximately 100 mm (4") |
| Weight | 3.2 kg (7 lb) |
| PNEUMATIC TUBING |
|---|
| Twin Tubing | 51416900 | Two 4.8 mm (3/16") polyethylene tubes bundled in polyethylene jacket. Rated for 35 bar (500 psi). Nylon tubing can be quoted on request |
| Splice Kit | 51401723 | Includes 3 brass unions, self-vulcanizing mastic pad, and sealing tape |
| Quick Connect Plug | 51407302 | Brass quick-connect fitting for input tube. Plug includes in-line filter and 90° elbow for insertion into panel |
| PNEUMATIC READOUTS |
|---|
| Compatible readouts include 256 pneumatic indicator. See separate data sheet for features and specifications |
