Das & Kumars

Mahmoorganj, Varanasi, Uttar Pradesh

Fast, Accurate Water Potential Measurements

Use the WP4C to measure water potential in 5 to 10 minutes. Range: -0.1 to -300 MPa*

Versatile

The WP4C can be used to measure the water potential of any porous material. It"s typically used to analyze soil, soilless substrates, plant material, and seeds, but it has been used to measure a variety of unusual things, including apples, bricks, oil, and insect carapaces.

Easy Operation

Simply place the sample in a round sample cup (4cm in diameter and 1cm tall) and set the cup in the lexan sample drawer, slide in the drawer and turn the knob to seal the chamber. After about 5 minutes, the WP4C will beep and show your final water potential reading.

Precise Mode

Measurements can be inaccurate if they"re made too soon. When run in Precise Mode, the WP4C checks to make sure the sample has reached equilibrium before displaying a final reading.

Faster Equilibration

The WP4C"s nickel Teflon sample chamber coating is hydrophobic. Less water absorption in the sample chamber means faster equilibrium.

Finely Tuned Calibration

The WP4C sensor is durable and easy to clean. The instrument can be calibrated using saturated salt solutions (mix your own or order single-sample vials of standards on the accessories tab). New algorithms let you fine-tune calibration for excellent accuracy (0.05 MPa or better).

Plug WP4C Data into HYPROP Data Evaluation Software

TheHYPROP FIT Softwarecan be used to plug in water potentail data collected by the WP4C for fitting different water retention models (i.e. van Genuchten, van Genuchten Bimodal, Brooks & Corey).

Learn More

How Does it Work?

Chilled Mirror Dewpoint Technique

The WP4C measures water potential by determining the relative humidity of the air above a sample in a closed chamber (an AOAC-approved method; also conforms to ASTM 6836). Once the sample comes into equilibrium with the vapor in the WP4C"s sealed chamber, the instrument finds relative humidity using the chilled mirror method. This method entails chilling a tiny mirror in the chamber until dew just starts to form on it. At the dewpoint, the WP4C measures both mirror and sample temperature with 0.001C accuracy.This allows the WP4C to deliver water potential readings with unparalleled accuracy in the -0.1 MPa to -300 MPa range

Limitations

The WP4C range goes to 0 MPa, but readings of samples wetter than -0.1 MPa will have an increasing, and typically unacceptable, percentage of error. Some users may be able to make useful measurements in samples wetter than -0.1 MPa using special techniques. For more information, see the WP4C User Manual.

Limits of the Method

At high water potentials, the temperature differences between saturated vapor pressure and the vapor pressure inside the sample chamber become vanishingly small. Because of this, the WP4C can now resolve temperatures to a thousandth of a degree. To read water potentials in the wet range (0 to -0.1 MPa), we recommend German manufacturer UMS"s fast responsetensiometersandHYPROPmoisture release curve instrument.

Direct digital readout displays instantaneous sensor output of 15 second averages. Measures mol, lux k lux or Wm-2. Meter automatically selects range with best accuracy and resolution for a given input signal so that measurements can be made in a variety of light environments. High quality amplifier provides automatic zeroing capability and long term stability. Calibration multipliers can be entered easily, and two sensor multipliers can be stored in memory. Licor Make, USA

Range: 199 mol s-1 m-2, 1, 999 mol s-1 m-2, 19, 999 mol s-1 m-2.
Accuracy: 25 oC: typically 0.4% of reading 3 digits on the least significant digit displayed (all ranges); 0-55. oC: typically 0.6% of reading 3 digits on the least significant digit displayed (all ranges).
Range Selection: Autoranging (3 ranges). Range: 199 mol s-1 m-2, 1, 999 mol s-1 m-2, 19, 999 mol s-1 m-2.
Resolution: 0.01 mol s-1 m-2, 1 mol s-1 m-2
linearity: 0.05%
Display: 4-1/2 digit LCD display, updated every 0.5 seconds in instantaneous mode.
Keypad: Sealed, 5-key tactile response keypad.
Power: One 9-volt alkaline battery (included).
Battery Life: 150 hours.
Weight: 0.57lbs.
Dimensions: 5.5L x 3 W x 1.5 D.

Ideal for educational use as well as for work in remote locations. The probe folds down into 3 separate sections measuring 16" each. This collapsible design allows you to easily pack the flowmeter in a backpack. Flow measurements can be taken in knots, km/h, mph, and m/s. The meter also takes temperature measurements in either F or C, including minimum and maximum temperature and current temperature. The basic unit includes meter, foldable probe, standard flow sensor and carrying case.
Also included is a wind speed impeller which allows you to take air velocity and wind chill measurements. To take flow measurements from a bridge or other elevated location, use the flow sensor with 15 meter cable (purchase seperately). The unit automatically turns itself off after 36 hours. Power: CR2032 Lithium battery (included). Provided with Backlight