Category precious stones

Jun 14 2013

how to degas your ultrasonic cleaner

Why Degas Your Ultrasonic?

Before the start of each working day it is best to degas the liquid in your ultrasonic cleaner tank.  This simple procedure allows the ultrasonic cleaner to work most effectively, since the ultrasonic waves can pass more freely through liquid than they do when air is mixed in the liquid in the tank.  If you are in a lab, or a dental, vet or medical practice this is the ideal time to prepare for your daily foil test.

You should also perform this task whenever you start with a fresh tank of water during the working day.  NB Take extra care when you empty your ultrasonic cleaner tank, as this is a risky time – see notes below.

Unless you are in a laboratory or clinical setting, where you will be completing a foil test to meet regulatory obligations, you can use the degas process to start your daily cleaning.  The first 10 minutes of degas/cleaning will be a little less effective than the rest of the day, but they will still generate a very good cleaning result.  Anyway, you’re paying for the electricity – you may as well get some value out of it.

How to Do It

  1. Fill the tank with the recommended amount of water and add a squirt of dishwashing detergent.  The detergent will help to soften the water which assists in the degas process.
  2. Degas the water in the tank.  Set heater thermostat to 60C.  After temperature is achieved run unit on cleaning cycle for about 10 minutes.  Degasing will expel the air so that the unit operates at optimum effectiveness.
    • NB If your machine does not have a heater, or if the heater is slow to increase temperature, you can boil water in a kettle to get the same result.  In a boil proof jug add two parts boiling water  to one part tap water.  If the tap water is room temperature (25C), the combined water will give you about 60C.  Adjust the mix for local conditions.

Notes:

  1. Foil Test. Always degas the tank before doing a foil test.
  2. Many desktop machines are designed to maintain minimum set temperature with their heater, but they can be rather slow to heat up, especially if ambient (or tap water) temperature is low. You can run the machine (e.g. start to clean some items) while the unit is heating.  This will usually only draw a small amount of additional electricity, but it will save time and help to get the tank up to operating temperature a lot quicker.  Covering the tank with its lid will also help speed the process.
  3. Empty Tank Safely. Some hints to safely empty liquid from your ultrasonic cleaner’s tank, for units without a tap.
    1. Water and Electricity Do Not Mix. Turn off power and disconnect unit from mains before emptying tank. Refill tank when unit back in designated safe working location and before power is reconnected to machine.  Remove all spills promptly and completely, ensuring that no water is on or near leads, plugs or power points.  Do not turn power back on until it is safe to do so.
    2. Cool Tank to 25C. Wait until liquid inside tank has cooled before emptying – you should turn heater off, or set thermostat to zero C and empty liquid only when contents has dropped to room temperature.  This will prevent damage to heater pad.
    3. Check for Lost Stones.  If you have been cleaning jewellery check that no stones have not come adrift from settings BEFORE you empty the tank. This problem is more common than you might think.  If you discover a setting is minus a stone use our procedure to find it in the tank, or ensure that you pass liquid through a fine sieve. Do not just pour liquid down the drain.
    4. Avoid Splashbacks.  Most ultrasonic cleaners are very well sealed around the top and sides of the unit.  But bench top ultrasonic cleaners will commonly have holes in the base or rear to allow for venting of excess heat from the unit.  So it is possible for liquid to enter the unit when tank is being emptied.  You would be amazed at where splashed water can end up. We recommend against vigorously upturning the unit to empty the tank, as this can cause unwanted liquid splash backs or internal components becoming dislodged.   Instead, use a household plastic jug to bail the liquid out (also makes it easier to use a sieve if searching for missing stones) and to wipe out the last bit of liquid in the tank with a clean sponge.  This procedure takes no more than a few seconds, but it can save a lot of time and money.

Liquid Glass Oz designs quality ultrasonic cleaners for commercial operations in Australia and New Zealand (N18973). 

www.liquidglassoz.com.au

Apr 12 2011

Saving Precious Stones from the Plumber’s Wrench

A recent question from an amateur jeweller is the inspiration behind this post.

The questions are

‘How to stop precious gems and small jewellery going down the sink?’

and

‘How to find diamonds at the bottom of a dirty ultrasonic cleaning tank?’

As a diamond setter, each and every time we set a stone the final test is to run it through the ultrasonic cleaner.  Naturally, this cleans the setting nicely before presenting it to the customer, but since it also  gives the setting a serious workout, for us it also serves as a practical test of how securely the stone has been set.  We often clean settings in the ultrasonic cleaner before working on a new job, so we can have a real good look at the piece before we start.

Every now and then the ultrasonic cleaner will loosen dirt which turns out to be the only thing that was holding a stone in place in its old setting – and the setting and stone will part company.  If that happens at the start of the day, when the cleaner’s tank is still pretty clean, it’s a very simple task to find the stray stone.  But after a big day, with lots of gunk floating about in the tank, it can be a major search and rescue operation.  What’s more, fishing inside a really dirty tank is not our idea of fun.

It’s worse, of course, to empty the tank, only to discover, too late, that the stone has gone down the drain.  The embarrassment of calling in the plumber will only be slightly less than telling the customer you’ve lost their diamond.  Clearly, these are situations we would all prefer to do without.

Avoiding the Loose Stone Scenario

Here’s how to avoid the problem in the first place:

  1. Place suspect pieces inside a small vegetable sieve.  Most kitchens have such items in a bottom drawer – the cheap plastic style with nylon weave is perfect.  HINT. If you don’t have a sieve an old lady’s stocking will do fine – just tie a knot in one end to hold the piece secure.
  2. Put the sieve, with setting/stone, inside the basket and run through cleaning cycle as required.  At the end of cleaning cycle remove the sieve and make sure the setting and stone are intact.  If the stone has come loose then at least it has been contained in the sieve and you can have it reset.  NB Do not heat the tank  – if you notice the sieve getting floppy, remove it promptly.
  3. If you forget to use a sieve, just make sure you do not dump the tank water without checking you have the stones first.  If you do lose a stone in the cruddy tank water, do not despair – read the hint below.

Finding and Retrieving Lost Treasure

OK.  You now have a clean setting, but it’s missing an expensive stone which you need to find before the owner comes to collect it.  Here’s the procedure:

  1. Do not dump the tank water.
  2. Apparatus: You will need to acquire two items:
    1. a large glass (see through) jar or bottle
    2. a big blob of bluetack
  3. Switch off power to the ultrasonic cleaner at the unit and at the powerpoint.  Detach lead from machine.  NB If water level is high you may have to remove some from the top – you will be inserting the jar or bottle, which will displace some water.  You don’t want spills from water going over the side of the tank.  HINT.  If you do need to remove water, drain from the top of the tank to minimise risk of scooping up the stone you are searching for.  Before dumping this water we would recommend pouring it through a fine weave sieve as well.  Check that the stone is not in the sieve before going any further.
  4. Firmly attach the blob of bluetack to the bottom of the jar or bottle.  Remove the basket from the unit.
  5. Carefully push the jar or bottle towards the bottom of the tank.  As the object goes deeper into the water, most of the crud will simply move away.  Through the glass bottom you will be able to examine the bottom of the tank for any objects that have fallen.
  6. Once the stone is found, steadily press the bluetack blob into the stone until it is firmly held against the glass base.  Then carefully remove the stone from the water.  Your salvage operation is now complete.
Liquid Glass Oz designs quality ultrasonic cleaners for commercial operations in Australia and New Zealand (N18973). 

www.liquidglassoz.com.au

Mar 28 2011

Testing Your Ultrasonic Works

Not sure that your ultrasonic is working properly?

The foil test is one test that can tell you if  it is.

Foil Test

The foil test is commonly used in medical, vet and dental practices, before the start of each day.  It is critical that surgical instruments are properly cleaned, then sterilised.  A properly functioning ultrasonic cleaner is the key to an effective cleaning process.

Preparation

  1. Fill the tank with the recommended amount of water and add a squirt of dishwashing detergent.  Detergent will help to soften the water.
  2. Degas the water in the tank.  Set heater thermostat to 60C.  After temperature is achieved run unit on cleaning cycle for about 10 minutes.  Degassing will expel the air so that the unit operates at optimum level.
    • NB If your machine does not have a heater you can boil water in a kettle to get the same result.  In a boil proof jug add two parts boiling water  to one part tap water.  If the tap water is room temperature (25C), the combined water will give you about 60C.  Adjust the mix for your local conditions.

Test Procedure

You will need a piece of kitchen aluminium foil large enough to cross the tank diagonally and to drop towards (but not quite to) the bottom of the tank, with some excess foil above the water, that you can hold onto.   The foil should be oriented vertically (ie hanging downwards) – if it is laid horizontal the test will be invalid. NB Do not allow body parts to touch or be immersed in the tank water at any time during cleaning operation.

passed foil test

Typical Result – 90 seconds in 100W Ultrasonic Cleaner

Run ultrasonic cleaner through a 10 minute cycle, while holding the foil above the water line, with the foil descending to just above the bottom of the tank, and hanging diagonally across the tank.

Remove and inspect foil.  A functioning ultrasonic cleaner will show evidence of the cavitation effect on the foil.  The more powerful the machine the more intense the reaction.  This may range from pin sized indentations in a light weight machine of say 30W, to foil being ripped to shreds in a larger unit (say 100W+).  Lack of indentations is a sure sign that machine is not working properly.  If you performed this test after delivery from the supplier you should advise the supplier and request return/replacement instructions.

Warning:  Some cheaper machines are named in a way that will deliberately mislead the buyer.  Unless the machine clearly states that it is an ultrasonic cleaner  customers should assume that it is not.   Ultrasonic cleaning pretenders will never pass the foil test.  Contact the supplier or your local Department of Fair Trading for further advice.

NB If you are in a medical/dental practice consult your practice manager or your practice procedure manual. Medical practices in Australia should refer to AGPAL if they need specific guidance.

Liquid Glass Oz designs quality ultrasonic cleaners for commercial operations in Australia and New Zealand (N18973). 

www.liquidglassoz.com.au