SATO KEIRYOKI SK-630PH Series User manual

Instruction Manual
SK-630PH Series pH Meters
No. 6416-00 Model SK-630PH
No. 6418-00 Model SK-631PH
No. 6420-00 Model SK-632PH
3-4, Kanda-kajicho, Chiyoda-ku, Tokyo 101-0045 Japan
URL: http://www.sksato.co.jp/english/

1
Introduction
Thank you for purchasing the pocket type SK-630PH series pH meters.
- These pH meters are designed to measure hydrogen ion concentration and liquid
temperature. Do not use it for any other purposes. (Note that the model SK-630PH is not
able to measure temperature)
- Read this instruction manual thoroughly before using the instrument and store it in a safe place.
Important safety instructions
Warning
These instruments are not explosion-proof. Never use them for flammable materials.
DANGER
RISK OF EXPLOSION
- Do not use the pH standard solutions for any purpose other than for calibration.
The solutions are not for drinking. Never try to drink it. If accidentally ingested, consult a
doctor immediately. (pH standard solutions are optional items, not included as standard
accessories)
- For any inquiries, contact the store where you bought the instrument or our service network.
Caution
Follow the instructions below when using these instruments.
- These are precision instruments. Be careful not to drop or knock it.
-Operating these instruments outside the temperature range may result in unit malfunctions.
Make sure to use the unit within the operating temperature range specified in this manual.
-Avoid using this unit in a place exposed to direct sunlight or near a heat source. Otherwise,
the unit may become deformed or malfunction.
-If this instrument is left in a car in the hot summer sun, it will become extremely hot and
may malfunction. Do not leave the unit in such a place.
- If this unit is used in an environment where electrical noise is generated, the display may
become unstable or the measurement error may increase.
- Never disassemble or modify the unit. Doing so may cause malfunctions.

2
- If the unit will not be used for a long period of time, always remove the batteries.
Otherwise, the batteries may leak, resulting in malfunctions.
- Do not dispose of used batteries in a fire.
- Keep the batteries out of the reach of children. If a child swallows a battery accidentally,
consult a doctor immediately
- For environmental protection, dispose of used batteries in compliance with local rules and
regulations.
- Do not wash or wipe this unit with alcohol, thinner, or other solvents. If the unit becomes
dirty, wipe it with a tightly-wrung towel or the like that has been dipped in warm water with
a neutral detergent.
- When the unit is first used or after it has been stored for several days, the pH
measurement response may be slower. In such cases, immerse the sensor terminal in
either the pH standard solution or water and let it stand for one hour (for more accurate
measurement, at least 12 hours in the standard solution) before use. Do not turn on the
unit during this immersion time.
- The glass electrode of this unit may be damaged or its useful life may be shortened if it is
used for liquids such as organic solvents, oils, adhesives, strong acids (pH 0 to pH 2),
strong alkalis (pH 12 to pH 14) and surface-active agents.
- The pH reading may become unstable when pure water is measured.
- If the pH standard solutions contact the skin (hand), immediately wash the contaminated
skin with running water. If the solution gets into the eyes, immediately rinse with water and
consult a doctor.
- Keep the pH standard solutions out of reach of children. If accidentally ingested, consult a
doctor immediately.
- This instrument is shipped with the batteries installed at the factory. The battery life of
these batteries may be short because they are designed for test purposes. If the battery
power is low, replace the batteries with new ones.

3
Overview
The SK-630PH series pH meters are designed to easily measure hydrogen ion
concentration (pH) and liquid temperature.
These can be calibrated at three pH points (4, 7 and 10), and provide reliable measurement
by using the built-in automatic pH measurement temperature compensation (Not applicable
for the model SK-630PH)
Note that the pH standard solutions do not come with the SK-630PH series pH meters.
Various types of pH standard solutions are available as options. Contact the store where
you bought the instrument or our service network for help with the standard solutions.
Features
- Compact, pocket-size
- Auto power-off
- Auto temperature compensation (* Not applicable for the model SK-630PH)
- Waterproof (In compliance with the IPX4 grade of the Japanese waterproof standard JIS C 0920)
Cautions before use
- Check that the instrument has not been damaged during transport. If damage is found,
contact the store where you bought the instrument or our service network.
- When the pH of food or drink is to be measured, take a sample (sufficient quantity so that
the electrode tip can be immersed at least 3 cm in the object) in a separate container for
measurement. Do not ingest the sample measured.
- The sensor section is made of glass. Take great care when handling the sensor section. If
it is damaged, be careful not to be injured by broken glass.
If the internal solution comes in contact with the skin (hand), immediately wash the
contaminated skin with running water.

4
Names of components
1. Main body
(1) Display : Displays measurement readings or status of the unit.
(2) PWR key : Press this key to turn on the unit. To turn off the unit, press the key again.
(3) CAL key : Enters the calibration mode.
(4) HLD key : Holds the value being displayed. Increments the pH value to be adjusted
in calibration mode.
(5) Glass electrode: Measures pH.
(6) Temperature sensor: Measures temperature.
(7) Glass electrode cover
(8) Battery cover
(9) Sensor cap
2. Details of the display
(10) pH reading (11) Temperature reading
(12) CAL: Calibration indication (13) ATC: Auto temperature compensation
(14) HOLD indication (only for SK-630PH) (15) Low battery mark (only for SK-630PH)
(16) Decimal point indication

5
Installing and replacing the batteries
(1) Remove the two screws on the battery cover. Be careful not to lose the screws and
packing.
(2) Remove the battery cover. The battery cover is designed to fit tightly on the unit to keep
it waterproof.
(3) Remove the four old batteries (LR44).
(4) Install the batteries by referring to the polarity marks on the battery compartment.
Use four new batteries. Do not mix new and old batteries together. Doing so may cause
malfunction or battery fluid leakage.
(5) Place the battery cover on the unit and secure it with the two screws.
Caution
- Immediately replace the batteries with new ones if the display is flashing. Otherwise the
measurement accuracy may be affected or malfunction may occur. LR44 batteries are
available at convenience stores, home centers and electric appliance stores.
- Securely fix the battery cover in place, otherwise the unit will not be waterproof. Also,
before fixing the cover, make sure that there is no dust or dirt stuck on the body packing. If
it is dirty, clean it before fixing.
- Do not try to remove the battery cover if the surface of the unit body is wet or there are
water drops on it. Otherwise, water may enter inside the unit and cause malfunctions.
Before measuring
(1) Press the PWR key. The display flashes for about one second to indicate that the unit
has been turned on.
(2) Perform the pH calibration after the battery change or when a very accurate pH
measurement is necessary.
(3) The unit is turned off by the auto power-off function if no key is operated for 20 minutes.
Turn off the auto power-off beforehand if measurement is to be done continuously.
⚫Canceling the auto power-off
Press the PWR key while pressing the HLD key at the same time to turn on the unit,
and then release the HLD key when the "n" character appears on the display.
Caution
Auto power-off becomes no longer cancelled once the unit is turned off. Perform the auto
power-off cancelling each time as necessary.

6
Calibration mode
By performing the 3-point calibration, this instrument can accurately measure the pH. To
ensure accuracy, calibration about once a day is recommended. To calibrate the SK-630PH
series pH meters, prepare the following items:
. pH 4 standard solution (phthalate solution) : pH 4.01 (at 25°C)
.pH 7 standard solution (neutral phosphate solution): pH 6.86 (at 25°C)
.pH 10 standard solution (carbonate solution) : pH 10.01 (at 25°C)
. Water (distilled, pure or tap water)
. Four beakers (Each beaker to contain one type of standard solution or water (distilled,
pure or tap water))
To ensure accuracy, perform calibration at the same temperature as the material to be measured.
* Various types of pH standard solutions are available as optional products. For details,
contact the store where you bought the instrument or our service network.
⚫How to calibrate the SK-630PH series pH meters
(1) Press the PWR key to turn on the unit.
(2) Remove the sensor cap and the glass electrode cover, and then thoroughly wash the
glass electrode with water (distilled, pure or tap water). Absorb the water on the glass
electrode by using clean filter paper, cotton swabs or tissue paper.
Be careful not to rub the glass electrode while absorbing water. Otherwise static
electricity will build up and the pH readings will become unstable.
(3) Immerse the glass electrode into the pH 7 standard solution. Do not move the
electrode and wait for three minutes.
(4) Press the CAL key. The CAL indication appears on the display. Press the HLD key to
set the pH calibration value to that of the standard solution.
The figures above show the displays when using the pH 7 neutral phosphate standard
solution of pH 6.85 (at 25°C).
NB: For the relation between the pH value of standard solution and the temperature, refer
to the section "Relation between pH value and temperature".

7
(5) Hold the set value until the "SA" indication appears on the display. In about 10
seconds, the display changes from "SA" to "En" to indicate that the set value has been
stored in the unit memory.
Note: Be sure not to press the CAL key before "SA" appears. If pressed, the calibration
ends and no setting can be stored in the memory.
(6) Wash the glass electrode with water (distilled, pure or tap water).
(7) Perform calibration at pH 4 and pH 10 by using the same procedure as for pH 7.
The figures above show the displays when using the pH 4 phthalate standard solution of
pH 4.01 (at 25°C).
The figures above show the displays when using the pH 10 carbonate standard solution of
pH 10.1 (at 25°C).
Caution
- The calibration is forcibly terminated in about ten seconds if the glass electrode is detected
as being dry or outside the operating calibration range. When terminating calibration, the
"En" indication (SK-630PH/SK-631PH) or "End" indication (SK-632PH) appears on the
display.
- The table below shows the pH value range to be set for calibration.
Calibration point
pH value range
pH 4
3.50 to 4.50
pH 7
6.50 to 7.50
pH 10
9.5 to 10.50
Note that it is not possible to perform calibration using the oxalate standard solution (pH
1.68 at 25°C) or borate standard solution (pH 9.18 at 25°C).

8
Relation between pH value and temperature
When performing calibration, set the pH value according to the temperature of the standard
solution as follows;
Standard solution
Name of solution
Temp.
pH value
Temp.
pH value
pH 4
Phthalate solution
0 ℃
4.00
30℃
4.02
5 ℃
4.00
35℃
4.02
10℃
4.00
40℃
4.04
15℃
4.00
45℃
4.05
20℃
4.00
50℃
4.06
25℃
4.01
-
-
pH 7
Neutral phosphate
solution
0 ℃
6.98
30℃
6.85
5 ℃
6.95
35℃
6.84
10℃
6.92
40℃
6.84
15℃
6.90
45℃
6.83
20℃
6.88
50℃
6.83
25℃
6.86
-
-
pH 10
Carbonate
solution
0 ℃
10.32
30℃
9.97
5 ℃
10.24
35℃
9.92
10℃
10.18
40℃
9.89
15℃
10.12
45℃
9.86
20℃
10.06
50℃
9.83
25℃
10.01
-
-
Measuring procedure
(1) Press the PWR key. The unit enters the measurement mode after the display has
flashed for about one second. (The decimal points on the display flash.)
(2) Remove the sensor cap and the glass electrode cover.
(3) Immerse the glass electrode at least 3 cm deep into the material to be measured.
Read the pH value when the reading becomes stable.
(4) To end the measurement, press the PWR key to turn off the unit. Wash the glass
electrode with water (distilled, pure or tap water) and store it.
(5) To protect the glass electrode from damage during storage, we recommend fitting the
electrode cover and the sensor cap. Also, to prevent the glass electrode surface from
becoming dry, it is effective to keep it in water (distilled, pure or tap water) or the pH
standard solution when not in use.

9
⚫Measuring soil pH
Mix soil and pure water in the ratio of 1 to 5 and stir it well. Then, measure the pH of
the supernatant water.
About the glass electrode
(1) Storage
If left unused for a long time, the glass electrode becomes too dry to measure the pH
accurately. The glass electrode works properly and shows accurate readings when it
is moderately moist. When using the instrument for the first time after purchasing or a
long storage period, we recommend placing the glass electrode in water (distilled, pure
or tap water) or the pH standard solution for at least 12 hours and performing calibration
before measuring the pH.
(2) Inspection and calibration
For accurate measurement, perform pH calibration using the pH standard solution. If
there is a deviation from the expected value, adjust it before performing a pH
measurement.
Note that there are cases where the pH value of the standard solution has changed
from its original value. This can happen if the pH standard solution is dirty or if it has not
been used for a long time. If necessary, use a new pH standard solution.
(3) Washing
Be sure to wash the glass electrode after each pH calibration or measurement with
water (distilled, pure or tap water). If left unwashed, the liquid measured tends to form a
film on the surface of the glass electrode, causing measurement errors. Always wash
the glass electrode after every time of use.
(4) Useful life
The glass electrode is a consumable. Its useful life varies depending on the material to
be measured, pH value or temperature.
(5) Deposit of white potassium chloride crystal
A deposit of white crystal is sometimes found on the tip of the glass electrode; this does
not pose a problem when using the instrument, and the deposit is easily washed off
with tap water. If it does not come off with tap water, soak the glass electrode in warm
water to remove it.
Do not lick or swallow the potassium chloride crystal. If the eyes or skin becomes
contaminated with the crystal, immediately consult a doctor.

10
Specifications
Cat. No.
6416-00
6418-00
6420-00
Model
SK-630PH
SK-631PH
SK-632PH
Measuring
Range
pH
2.0~12.0pH
2.0~12.0pH
2.00-12.00pH
℃
-
0.0~50.0℃
0.0~50.0℃
Accuracy
pH
±0.6pH
±0.5pH
±0.4pH
℃
-
±1.0℃
±0.5℃
Resolution
pH
0.1pH
0.1pH
0.01pH
℃
-
0.5℃
0.1℃
Elements
pH
Glass electrode
Glass electrode
Glass electrode
℃
-
Thermistor
Thermistor
Measuring ambient
0 to 50℃
Power Requirement
Alkaline Batteries LR44 (GPS76E ×4 pcs.)
Battery Life
About 200 hours continuous
Materials
Case ：ABS resin
Sensor：Glass
Dimensions
(W)36×(H)150×(D)25mm
Weight
About 65g (inclusive of batteries)
Functions
Three point Calibration function, Auto temperature compensation (*1)
HOLD. Auto power-Off, (possible to release the auto power-off)
Waterproof property
JIS C 0920「IPX4」
Standard accessories
Instruction manual,
Alkaline battery LR44(GPS76E) x 4 pcs: Factory set-
Alkaline battery LR44(GPS76E) x 4 pcs
*1. Not applicable for the model SK-630PH
Options
Cat. No.
Remarks
6401-00
Phthalate solution (pH4.01): 500ml (JCSS)
6402-00
Neutral phosphate solution (pH6.86): 500ml (JCSS)
6403-00
Carbonate solution (pH10.01): 500ml (JCSS)