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Enabling better global research outcomes in soil, plant & environmental monitoring.

Model 1515D Digital Chamber for Vehicles 100 Bar

The PMS-1515D Pressure Chamber Instrument is a new release. It is similar to the PMS-615D model however it has a maximum operating pressure of 100 bar (10 MPa). The PMS-1515D is a highly portable pressure chamber for growers making routine water measurements and irrigation scheduling. It can also be used in scientific research and for pressure volume curves. The digital read-out offers features such as backlighting and multiple pressure scales (Bar, MPa and PSI). Standard sealing option is a ¼ inch Compression Gland Gasket and Insert which is ideal for most woody plants. Other sealing options for bladed grass or other semi-round sizes are available.

Model 1515D Pressure Chamber Instrument is a new release with changes that most users will appreciate. It is a 100 bar digital instrument fully enclosed in a sealed case with an easily removable tank. It is similar to our Model 615 except higher pressure and digital readout. The Control Valve and internal piping have been upgraded to now allow direct connection to Nitrogen Cylinders with 207 Bar/3000 PSI pressure. The instrument is fitted with a 100 Bar Digital Gauge that offers features such as backlighting and multiple pressure scales such as (Bar, MPa and PSI).

Instrument comes fitted with our most popular sealing gasket size – 1/4 inch Compression Gland Gasket and Insert. This gasket will seal a sample that is 1/4 inch in diameter down to a completely closed position. If you need other sealing options such as bladed grass or other semi-round sizes check our other options.

This is an excellent choice for research due to the large range of operating pressure. It is good for work on high stress level plants, pressure volume curves but can also be used for routine water measurements for crop plants.

The instrument has a bail-spring handle for carrying and comes complete with a shoulder strap to lighten the load in the field. It has 5 tie-down rings for mounting to ATV or other transportation. The instrument comes complete with light weight aluminum nitrogen cylinder (20 cubic foot) that is secured with 2 inch heavy duty velcro straps and can be quickly replaced with a full cylinder.


Pressure Chamber Safety

General Warnings

  • Safety Glasses must be worn at all times when preparing the Pressure Chamber Instrument for use, using the Pressure Chamber Instrument, and trans-filling gas.
  • Working with high and low-pressure nitrogen gas requires safe handling, precaution and safety measures must be followed.
  • Nitrogen gas fittings, hoses and valves can fail. Safety measures must be followed to ensure that in the event of an accidental failure of any equipment the user will not be injured. Possible consequences of failure include but are not limited to:
  1. Dangerous whipping hose. Could cause injury to body or even death.
  2. Couplings or parts thrown off at high speed. Could cause bodily injury or even death.
  3. High pressure discharge of gas. Could penetrate skin and cause bodily injury.
  4. Catastrophic failure of fittings, hoses or valves could cause overwhelming discharge of Nitrogen Gas (N2). Risk of asphyxiation or oxygen deprivation in enclosed environment. Clear all persons from the area and ventilate in this event.

Appropriate and Intended Use

  • The Pressure Chamber Instrument must only be used for the purpose it was intended; that intended purpose is to pressurize plant samples in order to measure xylem water potential, extract xylem water or induce cavitation into plant samples. Any other process or use is not recommended and user could be injured or even killed.

Working Environment

  • Whenever operating the Pressure Chamber Instrument, be sure to operate in a safe environment. Lay the instrument on a flat surface when operating.
  • The Pressure Chamber Instrument should be operated and stored in temperatures no lower than 20 degrees Fahrenheit / -7 Celsius and maximum temperature of 120 degrees Fahrenheit / 49 Celsius. Outside of this range could cause damage to instrument.

Testing a Leaf

(Pressurization of a Sample)

  • Instrument should be prepared properly to work with the samples being tested.
  • Always fit the appropriate sized insert with appropriate sized gasket to ensure the sample does not extrude or shoot out of the lid. ½ inch Compression Gland Base should be used only with 3/8 and ½ inch sealing systems. ¼ inch Compression Gland Base should be used with 1/8 and ¼ inch and Almond sealing systems. Grass Compression Gland System should be used only with Grass Compression Gland Base.
  • Safety Glasses must be put on prior to pressurizing the instrument; they should be worn for the duration of the test until the instrument is fully depressurized and put away.
  • When viewing a sample, ensure your eyes are not directly over the sample. View from a slight angle. This will ensure your eyes are not over the sample if it accidentally extrudes or shoots out of the chamber lid.
  • If sample appears to move during pressurization, stop the process and ensure it is properly sealed and that you are using the best possible gasket, insert and Compression Gland Base for this sample.
  • If you cannot get a good seal on the sample, discontinue testing.

Transporting Instrument

  • Never transport the Pressure Chamber Instrument while connected to the portable tank. Whenever transporting the instrument, the instrument needs to be disconnected from the tank and hose, and it should be completely depressurized.

Damaged Instrument

  • In the event the instrument is dropped, struck or damaged it should be returned to PMS Instrument Company for evaluation prior to further use. Using damaged equipment could result in physical injury or death!
  • Each instrument should be inspected on regular intervals depending upon usage but at least annually. High Pressure Hose, High Pressure Fittings and instrument should be inspected for ware, cracks, leaks or any other damage that might cause danger to the user. Instrument should be in good working order prior to use! Failure to correct these problems can lead to injury or death!

Other Warnings and Considerations

  • These are basic guidelines and safety recommendations. User must consult and comply with local laws that might further govern the use of the instrument or use of compressed gases.

Disposal or Decommission of the Instrument

  • While the instrument should provide years of use, it is possible that at sometime it will be disposed of. Local recycling guidelines should be followed for disposal.

Principle of Operation
The pressure chamber can be thought of as measuring the “blood pressure” of the plant — except that for plants it is water rather than blood, and the water is not pumped by a heart using pressure, but rather pulled with a suction force as water evaporates from the leaves. Water within the plant mainly moves through very small inter-connected cells, collectively called xylem, which are essentially a network of pipes carrying water from the roots to the leaves. The water in the xylem is under tension. As the soil dries or humidity, wind or heat load increases, it becomes increasingly difficult for the roots to keep pace with evaporation from the leaves. This causes the tension to increase. Under these conditions you could say that the plant begins to experience “high blood pressure.”

Since tension is measured, negative values are typically reported. An easy way to remember this is to think of water stress as a “deficit.” The more the stress the more the plant is experiencing a deficit of water. The scientific name given to this deficit is the “water potential” of the plant. The actual physics of how the water moves from the leaf is more complex than just “squeezing” water out of a leaf, or just bringing water back to where it was when the leaf was cut. However, in practice, the only important factor is for the operator to recognize when water just begins to appear at the cut end of the petiole.

The Plant Moisture Stress (PMS) reading at any given time reflects the plant’s interaction with the water supply and the demand for water placed upon the plant by its environment. Since these factors are almost always changing, PMS is nearly always changing. The time of measurement therefore requires careful consideration — PMS is most at midday and least just before sunrise. Pre-sunrise PMS values will usually reflect average soil moisture tension, if the soil is uniformly irrigated. Midday PMS values reflect the tension experienced by the plant as it pulls water from the soil to satisfy the water demand of the atmosphere.

Maximum Operating Pressure: 100 bar
Chamber Construction: Solid Stock Stainless Steel
Read-out: Bourdon Tube
Bar – PSI Scale
Size (L x W x H): 56 × 38 × 26 centimeters
Weight: 16 Kg
Gauge: 2.5” Diameter Gauge
1/2 of 1% accuracy
100 bar (10 Mpa) range

Van Leeuwen, C., Tregoat, O., Chone, X., Bois, B., Pernet, D., & Gaudillere, J. P. (2009). Vine Water Status is a Key Factor in Grape Ripening and Vintage Quality for Red Bordeaux Wine. How can it be assessed for vineyard management purposes? Journal of International Science Vigne Vin, 121-134. PDF

Van Leeuwen, C., Tregoat, O., Chone, X., Gaudillere, J. P., & Pernet, D. (2008). Different environmental conditions, different results: the role of controlled environmental stress on grape quality potential and the way to monitor it. Proceedings of the 13th Australian Wine Industry Technical Conference, 39-46. PDF