Deltat-T's Tensiometer types SWT3, SWT5 and SWT6

Tensiometers type SWT3, 5 & 6

Excellent accuracy in wet and irrigated soils

Miniature and rugged models available

A range of loggable, water-filled, pressure transducer tensiometers to measure soil water potential in many different soil environments

Applications

These conventional, water-filled, ceramic cup tensiometers have good accuracy (± 0.2kPa) over the range 0 - 85 kPa, which makes them well suited to applications in water movement and water uptake studies, and in irrigation monitoring.

The SWT tensiometers require regular refilling and degassing after dry period; also the SWT3 and SWT5 are susceptible to frost damage. These factors can make operation at remote or inaccessible sites impractical. In these conditions and in dry soils, the Equitensiometer should be considered but for most applications in the 0-85 kPa range, water-filled tensiometers are the natural first choice.

Power supply and data logging

The tensiometers require a stabilised 10.6V dc, 1.3mA power source. A DL2e Data Logger, fitted with a TVB1 Voltage Regulator can power and log up to 30 tensiometers (or 60 with special cable arrangements)

Summary of characteristics

Shaded columns indicate models and variations available

*Description*	*Notes*	*Range of shaft lengths available*	*ceramic cup dims.*	*Measure-ment range*
Tensiometer, general purpose, shaft 300mm, type SWT3 (5m cable)	Lowest cost version. Can be easily refilled in the ground. Whole body filled with water-more prone to thermal effects than other models.	50 - 2000mm (available in 100mm increments)	50mm x 20mm dia	+10 to -70 kPa
Tensiometer, miniature, shaft 70mm, type SWT5 (5m cable)	Compact - cause minimal soil disturbance. Can be used in plant pots.	20 - 200mm (available in 20mm increments)	20mm x 5mm dia	+100 to -85 kPa
Tensiometer, rugged, shaft 300mm, type SWT6 (5m cable)	The water and pressure transducer are further below ground. Can be left installled in frost free zones.	50 - 2000mm (available in 100mm increments)	60mm x 24mm dia	+100 to -85 kPa

Non-standard cable lengths, up to 100m, are available.

		Delta-T's new catalogue: covering: Soil Water Content: ThetaProbe - introduction ; performance ; theory Soil Water Potential: Tensiometer ; Equitensiometer Pore water conductivity: Sigmaprobe theory Evapotranspiration: (Software and weather stations) Data loggers and readout units ; Application examples ;
A sowacs feature page			Back to Delta-T Feature Page Index	© Bruce Metelerkamp www.sowacs.com/feature/deltat/swp-swt.html last update : 14 August 1999