Robinair 75240 User Manual

SPX Corporation
655 Eisenhower Drive
Owatonna, MN 55060-0995 U.S.A.
Tech Serv.: 1-800-822-5561

Fax: [phone]

Customer Serv.: 1-800-533-6127

Fax: [phone]

Website: www.robinair.com

75240 Hand Refractometer

Operating

Instruction

Sheet

WARNING!
damage resulting in personal injury:

To prevent equipment failure or

Read and follow all warnings in this

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instruction sheet before operating this
unit. If the operator cannot read
English, operating instructions and
safety precautions must be read and
discussed in the operator’s native
language.

- Si el operador no puede leer el inglés,
las instrucciones de operación y las
precauciones de seguridad deberán
leerse y comentarse en el idioma
nativo del operador.

- Si l’utilisateur ne peut lire l’anglais,
les instructions et les consignes de
sécurité doivent lui être expliquées
dans sa langue maternelle.

Always wear eye protection and

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protective clothing when working with
refrigerants and sulphuric acid.
Contact with refrigerants and
sulphuric acid may cause personal
injury.

Do not drink antifreeze (propylene or

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ethylene glycol base) or solution
(sulphuric acid base). If swallowed,
give two glasses of water and induce
vomiting. Call a physician.

SPECIFICATIONS

Style: Battery/Coolants
Model: 75240
Range: – 60°F
Resolution: 10° F; 0.01 sg
Size: 27 x 40 x 160 mm
Weight: 176 g

32° F / 1.15 ˜ 1.30 sg

˜

1. Prism

2. Cover plate

3. Correction screw

4. Mirror tube (holds the reticle scale)

5. Eyepiece (focusing ring of diopter)

Accessories

Eyeshade Screw driver Leather cover
Glass rod Soft cloth

Application

The 75240 Hand Refractometer is a portable, precision
optical instrument used for measuring the freeze point
of engine coolant and the operation state of battery
charging liquid. It is used on transportation vehicles,
such as cars, tractors, tanks, ships, etc., which use
propylene or ethylene glycol for coolant and sulphuric
acid for charging liquid.

When a liquid (such as coolant or charging liquid) is
placed on the prism, the light passing through it is bent.
The more concentrated the liquid, the more the light
will bend. The refractometer contains a reticle, or scale,
that is enlarged through the eyepiece to measure this
bent light.

The values of the scale have been established to
evaluate the coolant or charging liquid.

518712 Rev. A - (1/22/03)

The reticle without
any liquid on the
prism.

The reticle with liquid on the
prism. The reading is taken at
the point the shadow line
crosses the scale.

Operating Instructions

Use the following instructions to operate the 75240
Hand Refractometer.

IMPORTANT: Read and understand all Operating
Instructions and Helpful Hints before operating
the Refractometer.

1. Aim the front end (prism [1] and cover plate [2] end)
of the refractometer toward a bright light; then adjust
the focusing ring of the diopter (5) until the reticle
(scale within the mirror tube) can be seen clearly.

2. To set the Hand Refractometer to a null or zero
point -

(a) Open the cover plate.
(b) Place one or two drops of pure distilled water

on the surface of the prism.
(c) Close the cover plate and press it lightly.
(d) Through the eyepiece, observe where the

shadow line falls.
(e) If necessary, adjust the correction screw (3)

with the screw driver provided to make the

shadow line coincide with the water line.

The Hand Refractometer should now have a null point,
and you are ready to begin measuring.

3. Open the cover plate, and wipe the water off the
surfaces of the prism and cover plate with the soft
cloth that is provided.

4. Then place one or two drops of the liquid needed to
be measured on the prism surface.

WARNING: To prevent personal injury, use
glass rod provided when measuring battery
liquid.

Close the cover plate and press it lightly. The reticle
reading on the shadowline is the freeze point of the
liquid, or an indication of the operation state of the
battery liquid.

5. After measurements are taken, wipe the liquid
completely from the prism surface with the soft cloth
and let dry.

CAUTION: To prevent damage to the
refractometer, do NOT use water to wash the
instrument.

6. Replace the refractometer in its case, and store it in a
dry, clean area.

Helpful Hints and Maintenance

The distilled water and the liquid to be measured

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should be at the same temperature.
Null point should be adjusted once every 30 minutes.

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Clean prism completely to prevent residual impuri-

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ties, which could cause error during measuring.
The refractometer is a precision optical instrument;

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handle with care. Do NOT touch the optical surfaces.
Avoid strong shock during transportation.

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