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Ensure accuracy and safety through the correct method!
Recommended Cleaning Procedures for Electronic Balances
1. Why is cleaning necessary?
If dust or sample residue remains on the weighing pan, it may cause a slight difference in weight, thereby compromising weighing accuracy. In addition, cross-contamination due to the mixing of different samples can cause serious safety issues depending on the sample. Furthermore, leaving instruments in a dirty condition can lead to premature deterioration of the instruments.
In short, to use your precious electronic balance accurately, safely, and for a long time, it must be cleaned at an appropriate frequency.
2. What is the appropriate frequency of cleaning and what should be taken care of on a regular basis?
It depends on the sample to be weighed and the degree of dirtiness, but it is best to perform the cleaning after each use. In addition, it is recommended to have an SOP (Standard Operating Procedure) to check for dirt before each use.
When using the balance, try to keep it as clean as possible. For example, when weighing powders, use containers such as folded wrapping paper or weigh boats, do not blow on them, and (for balances with breeze breaks) place the sample in the container outside the breeze break if possible.
3. For safe cleaning
Turn off the balance (unplug the AC adapter) beforehand.
If the samples that were weighed are hazardous to the human body, take sufficient safety precautions such as wearing rubber gloves, masks, coats, and goggles. When the person tasked with weighing and the person tasked with cleaning are not the same, it is important that the latter is informed about the nature of the samples that were weighed.
4. Cleaning method (when the sample is relatively harmless)
A) If powder is spilled
Sweep it out using a bristle brush (* An animal fiber bristle material is ideal as it is not easily charged. Foam brushes are not recommended). Remove the weighing pan, pan support, breeze break ring, dust plate, etc.i, and sweep out any powder remaining under them. When doing so, move the brush from the inside to the outside to prevent powder from entering the balance through the gaps around the pan support boss (also be careful powder does not enter the balance when removing the pan support, etc.). Clean the areas other than around the weighing pan, such as the display, if they are covered with powder.
Finally, dry wipe with a lint-free tissue, paper towel, or cloth to remove minor dirt, and then put the removed parts back together.
For cleaning dust and powder, AX-CLEANING-SET, which includes two sizes of bristle brushes (animal fiber) and a chamois leather cloth, is useful.
B) If liquid is spilled
Wipe up with a lint-free tissue, paper towel, or cloth. As with the case of powder, remove the weighing pan, pan support, breeze break ring, dust plate, etc., taking care not to allow any liquid to get inside the balance, and wipe off any liquid remaining underneath. Clean the areas other than around the weighing pan, such as the display, if they are covered with liquid.
If the stain is sticky or difficult to remove, wipe it off with water or mild detergent. For unpainted metal partsii, ethanol or isopropanol (IPA) may be used. However, avoid using other organic solvents or abrasives.
Once the surfaces are sufficiently dry, put the removed parts back together.
When cleaning an analytical balance whose breeze break is readily removableiii, it will make the task easier if you remove the breeze break first. Also, be sure to clean the rails of the breeze break doors thoroughly, as dust accumulated on the rails can not only cause cross-contamination but also prevent the doors from sliding smoothly (* this is not a concern for analytical balances with fully hanging breeze break doors and no underlying railsiv).
[Other precautions]
► Do not use air to blow away powder or liquid. They may get into the gaps or inside of the balance.
► Do not spray cleaning solution (mild detergent, ethanol, etc.) or pour it directly from the container, but be sure to apply it by moistening a cloth or similar with it first. Otherwise, the solution may get into the inside of the balance.
► Do not apply force to the pan support boss or wipe strongly while the weighing pan and pan support are attached to the pan support boss. Doing so may damage the weight sensor.
► Do not deform the diaphragm around the pan support boss of a dust/waterproof balance. Doing so may degrade the dust/waterproof performance.
5. Cleaning method (when the sample is hazardous)
First, as mentioned above, please take sufficient safety precautions such as wearing protective equipment before carrying out the task.
In addition to the weighing pan, pan support, breeze break ring, dust plate, etc., remove the breeze break of the analytical balance if it can be removed. Moreover, if the breeze break is designed so that you can disassemble and reassemble it by yourselfv, disassemble it as much as possible.
Wipe the balance body and each component carefully with a lint-free tissue, paper towel, or cloth moistened with mild detergent. The balance body includes not only the area around the weighing pan but also extends from the housing to the display. The area surrounding the balance should also be wiped carefully, as there may be harmful samples attached to it. Metal parts (weighing pan, breeze break ring, dust plate, etc.) can be sterilized by autoclaving if necessary.
Breeze breaks coated with antistatic agent (mainly plastic breeze breaks) will gradually lose the antistatic agent after repeated wiping with water or mild detergent. In such cases, apply a commercially available antistatic agent. On the other hand, wiping with ethanol or isopropanol (IPA) will not only quickly remove the antistatic agent but also lead to cracking and deterioration. As explained above in "4. Cleaning method (when the sample is relatively harmless)," the use of ethanol or isopropanol (IPA) should be limited to unpainted metal parts. Other organic solvents and abrasives should not be used on any part of the balance.
As to other precautions, please refer to those described in "4. Cleaning method (when the sample is relatively harmless)" as the same precautions apply.
6. After cleaning
Before using the balance, turn it on and allow it to warm up sufficientlyvi. Ensure that it is level and that each component is properly installed. Then, place a weight on the balance to check its accuracy, and if it does not meet the criteria, perform a sensitivity adjustment using the internal weight or an external weight. * It is recommended that these processes also be defined in an SOP (Standard Operating Procedure).
7. Other
Dust and waterproof (IP65) balances such as the GX-AWP/GF-AWP series and FZ-iWP/FX-iWP series can be cleaned by pouring water directly on themvii. Especially at locations where balances are easily soiled, these balances make cleaning much easier.
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i Depending on the balance model, there are differences in supplied parts and parts that can be removed. Please check the instruction manual of each balance in advance.
ii Use on resin or vinyl parts (such as cables) may result in cracking or deterioration.
iii Such as the GX-A/GF-A series and HR-AZ/HR-A series.
iv Currently, the BA-T/BA series is of that type.
v The breeze breaks of the BA-T/BA series, including the inner small breeze breaks, can be disassembled down to individual pieces of glass.
vi Refer to the instruction manual of each balance for the time required for warm-up.
vii Please refrain from applying a water jet from the underside of the balance or immersing the balance in water.