The 1505D-EXP Pressure Chamber Instrument comes with all the normal features of our digital pressure chamber and in addition comes with a Cavitation Chamber. The instrument can be used for either Cavitation work or Pressure Chamber work.
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.
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 recognise 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|
|Cavitation Chamber Construction:||Solid Stock Stainless Steel|
|Read-out:||Digital Gauge (Reads in Bar, MPa or PSI)|
|Size (L x W x H):||33 × 28 × 24 centimetres|
|Gauge:||2.5” Diameter Gauge
1/2 of 1% accuracy