Optimal application scenarios for pin-type and pinless moisture meters
In many cases, it may be necessary to test the moisture content (% MC) of certain substances. Moreover, when directly testing the moisture content of materials, there are two main options - needle type water needle moisture meter and needle free moisture meter - which are good timing for use.
The needle type moisture meter uses the principle of resistance to measure the moisture content in various materials. Since water is a conductor, materials such as wood, cotton, gypsum, and hay are all resistors, and the easier the current flows through the material, the wetter it becomes. For the sake of precision, it is important to ensure that the needle instrument is calibrated for the specific material being tested - as different materials have different inherent current resistances.
On the other hand, needle free hygrometers use electromagnetic radio frequency to "scan" material samples to determine the presence of water. The fluctuation of electromagnetic waves is used to measure the amount of water in a sample. The accuracy of the needle free moisture meter is affected by the specific gravity (SG) of the scanned material, so it is necessary to calibrate the instrument for the SG value of the material. Specific gravity is a measure of the relative density of a material compared to another material (usually water).
Both needle and needle less hygrometers have their unique advantages and disadvantages, which may make them more or less suitable for specific humidity testing situations. When should a needle type moisture meter be used and when should a needle free moisture meter be used? The following is a broad scenario where one hygrometer may be better than another.
Needle free moisture meter
Test moisture in uneven surfaces and loose filling materials
Needle free hygrometers require complete contact with solid surfaces to provide accurate readings. If the scanning board cannot be completely placed flat on the tested material, the accuracy of the needle less hygrometer will be affected. In addition, if the scanned material is loosely packaged (such as for insulation or hay), the instrument may ultimately test the moisture content of the air between the fibers of the material.
On the other hand, a needle hygrometer can be easily used to test materials that are loosely packed or have uneven surfaces. The important thing is the current in the tested material - as long as there is a path for current to flow from one pin to another, the test can be completed. However, in order to test the moisture content in fiberglass insulation materials, hay bales, etc., specialized electrodes may be required.
Selection: Needle Moisture Meter
Test the moisture in materials that you do not want to damage
Needle free hygrometers are sometimes referred to as "non-invasive" or "non-destructive" hygrometers because they do not have to penetrate the surface of the material being measured to obtain accurate moisture content measurements. That's why many flooring professionals use needle less hygrometers to test the humidity of their hardwood flooring. By using a needle free instrument, moisture content can be evaluated without damaging hardwood flooring.
On the other hand, a needle hygrometer needs to penetrate the surface of the material for appropriate testing. In applications that require protection of the surface condition of the final product, leaving pinholes, even small pinholes that are easily filled or filled with epoxy resin, is usually not satisfactory.
