Digital refractometer PAL-1
Hand refractometers types HR 10, 20 and 53
Digital refractometers PR-32a and PR-101a

drawing up a diagram / determining the conversion factor "F"

The new digital refractometer PAL-1 encompasses all advantages of usual digital and hand refractometers. The PAL-1 is so small and compact that it fits into every pocket. Measurements can be made very easily at any place. Because of the digital indicator, reading mistakes are impossible. In addition, the PAL-1 is fully serviceable also in bad light conditions. The PAL-1 guarantees an optimal and quick determination of the concentration of aqueous coolants. The PAL-1 provides an excellent price/performance ratio.

To rapidly determine and control the concentration/mixing ratio of aqueous coolants (emulsions and solutions).

• Determination and checking of new and used emulsions and solutions can be done in a few moments, directly at the machines, in the work shop or in the laboratory.
• Considerably more exact method of determination, tolerance +/- 0,1, respectively 0,2, with regard to the concentrate
• Clean measuring method with minimal amounts without using separating chemicals.
• Small dimensions that make it possible to take the instrument to the factory measuring instrument in pocket size, easy to handle
  

Measuring principle The measuring method is based upon the principle of total reflection of light beams that impinge at a certain angle on the liquid that is to examine/measure. These light beams are refracted as a function of the concentration. While measuring there appears an easily readable light blue boundary on the instruments scale. The concentration is determined by the scale value and the respective concentrate factor. Instead of a calculation from the reading value and the factor, an evaluation can also be made by a nomo- or diagram. Hereby, an immediate reading of the concentration, respectively the mixing ratio is possible. Description The construction of the TESTRÖ-Handrefractometer is shown in this picture: Technical data MASTER-10M (HR 10) MASTER-20M (HR 20) MASTER-53M (HR 53) scale range 0-10 0-20 0-53 scale divisions 0,1 0,1 0,2 scale accuracy 0,1 0,2 0,2 dimensions according to type: max. 200 mm long, 35 mm Ø weight including box: approx. 400 g Measurement Put one or two drops of sample on the prism (Figure-1) Close the Daylight plate gently (Figure-2) The sample must spread evenly over the prism surface. Air bubbles should be eliminated (Figure-3) View the scale through the eyepiece. To focus, turn the eyepiece in either direction until clear (Figure-4) Read the measurement value where the boundary line intersects the scale (Figure-7) Wipe the sample off with a wet tissue (Figure-8) Calibration This refractometer needs to be calibrated before being used for the first time each day. Moreover, if the ambient temperature changes during the day, it needs recalibrated. Put one or two drops of distilled water or tap water (Figure-1) Close the Daylight plate gently (Figure-2) Distilled water or tap water or solution must spread evenly over the prism surface. Air bubbles should be eliminated (Figure-3) View the scale through the eyepiece. To focus, turn the eyepiece in either direction until clear (Figure-4) Confirm that the blue boundary line coincides with "0%" on the scale (Figure-5) If the boundary line does not coincide with "0%", turn the scale adjustment screw with a screwdriver until it does (Figure-6) Cleaning and maintenance The measuring instrument is to be kept dry and, if possible, in its case. After use the prism and the light sensor plate have to be cleaned with water and wiped dry. (Figure-8) Parts of the accessory are intended for this procedure.

TESTRÖ-Digital refractometers PR-101a and PR-32a

For the optimal and quick determination and control of the concentration / mixing ratio of aqueous lubricants (emulsions and solutions) and other liquids. water proof design!

Measuring principle
The TESTRÖ Digital Refractometer PR 32a is based upon the principle of refraction. It was not only developed in order to check the parts of materials in an aqueous solution in percentage, but also to determine the final reaction values and mixing ratios of chemical compounds. So, virtually every concentration deviation of a mixture from the target value can be determined quickly and exactly.

Characteristics and advantages over the hand refractometers
In contrast to the hand refractometer the digital refractometer has the following advantages:

Prominent functions and quick measuring time After years of development we can satisfy the customer's demand for automatic measuring of concentrations. This measuring method has been made possible because of a unique refraction sensor. An integrated micro computer operates the automatic temperature compensation. The calculation takes place immediately and guarantees an accurate measuring. A correction of the scale value by the temperature coefficient is therefore not necessary. Digital indication: the new standard of reliability A large liquid crystal indicator displays a well legible measuring result. Thus, reading mistakes or optical founded display errors are impossible. corrosion free sample measuring face of stainless steel The corrosion free sample measuring face of stainless steel (V2 A) withstands all aggressive media and liquids. The measuring vat is easy to clean and disposals of earlier measurements are easy to remove. Cast prism guarantees the measuring accuracy A cast prism (contrastive to a ground prism) guarantees a non distorted light passage and exact measuring results.

compact and handy design The light weight (295g) and the small dimensions make the digital refractometer the ideal pocket device. So, you can carry out the concentrate determinations everywhere at any time. prevention of incorrect measuring The integrated microprocessor checks if a calibration with water has been made (zero adjustment). If the calibration has been forgotten, the display shows "AAA". At the same time the microprocessor detects if there is no more sample liquid in the measuring vat or if the liquid exceeds the measuring range of 32% Brix. Modern sensor technique enables independence of light An integrated quartz light with a certain light frequency and illumination (red light) permeates the prism and the sample liquid. The emitted light is measured by light sensitive sensors and converted by the computer into the measuring value. Because of this, optimal results are also reached in ill lit rooms.

Recfraction scheme of the PR 101a Specified technical data measuring range Brix 0-45% (PR-101a) Brix 0-32% (PR-32a) minimum indication Brix 0,1% measuring accuracy Brix ±0,1% automatic temperature compensation +5-40°C zero adjustment by pressing the button after applying water onto the prism measuring time 3 seconds sample volume >= 0,1 ml dry cell battery 006 P dimensions 170x90x40 mm weight 295 g A short instruction for determining the concentration Filter the liquid you wish to determine with the accessory (delivered on request) Apply a few drops of tab water onto the prism surface (zero adjustment of the PR - 101a) - picture 1. Press the calibration button for adjustment to the surrounding temperature - picture 2. Remove the water with the cleansing tissue - picture 3. Apply the emulsion or solution you wish to determine onto the prism (picture 1) Having pressed the start button, the measuring result appears on the display after three seconds. The value is saved and displayed for five minutes - picture 4 and 5. After determining the concentration clean the prism with water and a tissue (accessory) - picture 3. Important information: As long as the aqueous material shows the factor 1, the displayed value is also =%. If not, the conversion factor has to be determined, or alternately a dia- or nomogram has to be drawn up (instruction available). If you want to avoid both, please ask the supplyer of the concentrate for details. An instruction for drawing up a nomo- or diagram for determination of the factor -F- is delivered with the order.

Instruction for drawing up a nomo- or diagram and for determining the conversion factor "F" for determining the concentration by TESTRÖ-Hand Refractometers HR 10,20,32

A) Drawing up a nomo- or diagram

The nomogram and the diagram respectively can be drawn up for every cooling lubricant without difficulty. Just produce three emulsions or solutions of exact volume concentration (water and concentrate should have a temperature of 20°C) and determine, by multiple repetition, the scale values for the three calibration concentrations. The average values are drawn into a diagram (ordinates = scale value; abscissa = measured concentration). In case of appropriate implementation the values lie on a straight line. From this line the "real concentration value" correlating to every scale value can be read. Thus, to every point on the line there belongs a reading and a concentration value. By juxtaposing these number pairs there ensues the nomogram for the respective coolant.

Please note that the refraction is highly dependent of temperature. Thus, all measurements have to be carried out at the same temperature (normally 20°C). Otherwise an appropriate correction will be necessary.

B) Determination of the conversion factor "F"

The following methods are possible:

a)	The conversion factor "F" is numerically identical with the specific concentration value of the dia- or nomogram, that corresponds to the refractometer scale value 1.0, and can therefore be deduced from above mentioned documents.
b)	In general, the conversion factor "F" can also be determined from the refractometer scale value of one single emulsion or solution of known concentration by dividing the concentration value by the scale value.
	example: concentration (measured) 4.0 refractometer scale value 5.0 conversion factor "F": 4.0 / 5.0 = 0.8 comments: the method according to b) is naturally less reliable.

C) General Remark

Provided that you do not want to draw up a dia- or nomogram (optional) or determine the conversion factor "F" on your own, we recommend to ask your distributor for the dia- or nomogram or for the factor of the in question coolant.
In both cases it would be necessary that the determination and the control of the concentrations / mixing ratios of the coolants ensues with a TESTRÖ Hand Refractometer.