Understanding Ultrasonic Cleaning Chemistries

Elma tec clean formulasWhile most of our ultrasonic cleaning posts provide practical advice on how to clean specific items there’s more to the science of the process.   In fact effective ultrasonic cleaning is a combination of ultrasonic frequency and power, the temperature of the cleaning solution, the time it takes to complete the job, post-cleaning procedures if required, and cleaning solution chemistry.

 Three Cleaning Solution Chemistries

A wide variety of cleaning solution chemistries are on the market but just about all commonly used solutions fall into three categories: alkaline, acidic and neutral. While terms like alkaline and acidic may cause some initial concern we are confining our examples to highly diluted biodegradable … Read the rest

How to Clean Fiber Optic Subassemblies

Ultrasonic cleaning is a proven technique for fast, safe removal of polishing compounds and other contaminants from optical fiber subassemblies.  The compounds are used to polish mating surfaces to a perfectly smooth flat surface. Scratching during cleaning is unacceptable.  Total cleaning is crucial to avoid potential damage to other components in an assembly.

Specifying an Ultrasonic Cleaner and Procedure

Ultrasonic cleaning works on the principle of cavitation, the implosion of millions of microscopic bubbles when they contact surfaces immersed in an ultrasonic cleaning solution.  The implosions, which occur on any surface wetted by the solution, dislodge and carry away the contaminants.  This is faster, safer and more efficient than manually cleaning optical fiber surfaces.

Ultrasonic frequency, measured in kilohertz (kHz) or thousands of cycles per second, is an important criterion in specifying an ultrasonic cleaner.  High frequencies such as 80 kHz create bubbles that are relatively small and gentle and … Read the rest

Achieving Uniform Sonication in an Ultrasonic Cleaner

Uniform distribution of sonic energy in an ultrasonic cleaning solution or water bath used for sample prep provides two benefits.  In a cleaning exercise parts are evenly exposed to cavitation action, resulting in more uniform cleaning.  The same uniformity results when the tank is used to sonicate samples in flasks or beakers.

A modified benchtop laboratory ultrasonic cleaner, the Elmasonic P30SE now available from Tovatech, demonstrates superior performance in delivering uniform sonication while providing a full range of operating options unavailable in conventional benchtop units. Elma researchers determined that the main impediment to uniform sonication was interference due to the tank drain duct.  It was visually demonstrated in a drain-equipped unit that cavitation in a beaker suspended on the drain side of the tank was not nearly as vigorous as in the beaker on the opposite side.  Therefore, the new P30SE has no drain and demonstrates homogeneous sonication.

Other Processing Read the rest

A Primer on HPLC Flowmeters

High performance liquid chromatography – HPLC – is very often the method of choice for analyzing pharmaceutical compounds starting with R&D and continuing into manufacturing.  Among other things it is used to

  • Check candidate drugs for purity
  • Monitor changes in pharmaceutical intermediates during chemical synthesis scale up
  • Test the stability and dissolution of formulations in development and
  • Support quality control in final drug products

Identifying an analyte by HPLC is based on accurate and reproducible column retention time as it passes through an HPLC system.  Reproducible retention time is critical and depends on uniform, reproducible HPLC pump flow rates.  A leak developing or other malfunction in the HPLC system will result in analysis errors.  Obviously, then, continuous testing is necessary to insure that the HPLC system is properly calibrated.  This is called operational qualification. OQ starts before the HPLC system is put into use and as part of ongoing system … Read the rest

An Ultrasonic Cleaner Design for Food Laboratories

Food laboratory technicians charged with cleaning sieves used to inspect raw materials for correct grain size may welcome a specially designed ultrasonic cleaner developed by acoustic R&D engineers at Elma Ultrasonic in collaboration with food lab personnel  at two locations.   

The result of this collaboration is the Elma S50R ultrasonic cleaner available from Tovatech.  It is optimized for sieve cleaning, but also for degassing HPLC solvents and for sample preparation involving difficult-to-dissolve substances.   A unique feature of the S50R is its built-in programming:  food scientists can select three programs by pressing the corresponding key on the cleaner’s control panel:  sieve cleaning, degassing and sample prep. There is also an on-off key for standard cleaning and a timer showing set and remaining time.

Sieve Cleaning Challenges Solved

While ultrasonic cleaning is safer and gentler than using brushes to dislodge particles trapped in lab sieves thoroughness has been a problem due to … Read the rest

How Ultrasonic Cavitation Bubbles Scrub

Pardon us for the take-off on a well-advertised household cleaner.  We have many posts describing how the implosion of cavitation bubbles in an ultrasonic cleaner solution removes contaminants from wetted surfaces. Here we’ll take a look at what happens at the bubble/surface interface in an ultrasonic cleaner.

Airless Bubbles

Let’s start by saying that unlike the household cleaner bubbles cavitation bubbles have no “air” inside.  Instead they have a vacuum.  The nitty-gritty of how is not as important as what happens.

Except to say in brief, cavitation bubbles are created by ultrasonic transducers bonded to the bottom and/or sides of the ultrasonic cleaner tank.  The generator-driven transducers cause a vibration on the tank surface to produce sound waves in the cleaning solution.  This causes compression and expansion in the liquid leading to cavitation bubbles that implode violently and produce shock waves radiating from the site of the collapse.

What is … Read the rest

How to Remove Jewelry Polishing Compounds

Watch case manufacturers, class ring manufacturers, earring manufacturers, body jewelry manufacturers and other quality jewelry manufacturers with broad markets can quickly and efficiently remove jewelry polishing compounds with an industrial ultrasonic cleaner.  Following the removal of jewelry polishing compounds final cleaning can be accomplished with the ultrasonic cleaner and/or steam cleaning before products are shipped.

Why Ultrasonic Jewelry Polish Removal?

In a word: efficiency.  Ultrasonic cavitation, the implosion of microscopic bubbles against the surface of the jewelry, safely and quickly dislodges and carries away jewelry polishing compounds and other dirt from all surfaces including those difficult or impossible to remove by manual methods.  The action is performed in an ultrasonic cleaning tank filled with a biodegradable cleaning solution excited by ultrasonic transducers powered by a generator.

An example of an ultrasonic system to remove jewelry polishing compounds is the dual-frequency Elmasonic X-tra basic line available from Tovatech.  It is available … Read the rest

How to Comply with New CDC Vaccine Storage Guidelines

Ongoing instances of vaccine spoilage due to improper storage and inattention to expiration dates has prompted the CDC to issue its “Interim Vaccine Storage and Handling Guidance.”

The CDC guidance and related documents are designed to help healthcare facilities plan procedures and equipment procurement related to the storage of vaccines.

Compliance is particularly important if clinics participate in government-sponsored vaccination programs such as Vaccines for Children. CDC is currently evaluating the most efficient and cost effective method to phase in the recommendations.  More guidance is coming.

CDC Vaccine Storage Guidelines; Tovatech Suggestions

We summarize the current CDC document here with our own suggestions on how healthcare facilities and clinics can take steps to protect their investment in vaccines from the time of receipt to administering.

Guideline:

Use a biosafe glycol-encased probe or a similar temperature-buffered probe rather than measuring ambient air temperatures; provide a hi/low alarm system to alert personnel … Read the rest

How to Avoid Analytical Balance Weighing Errors

The Kern ABT analytical balance with automatic internal calibration
The Kern ABT analytical balance with automatic internal calibration

Precision weighing with an analytical balance requires care and alertness on the part of the operator. Many factors can influence the performance of an analytical laboratory balance.  Where precision is paramount an error of 0.001gram or smaller can be significant when strict regulations apply.

How Lab Balance Errors Occur

In simple terms, digital analytical balance errors arise when the instrument inaccurately records the weight of the sample due to influences that can occur without the operator’s knowledge, or because of poor weighing practices.  Influences can be external or internal.

Although externally induced errors can be caused by many factors, they are easy to reduce or eliminate.  Usually these causes are traced to lapses in precision balance operating procedures relating to the sample and the laboratory environment.  Here are some suggestions on reducing external sources of balance weighing errors.  Note that some … Read the rest

How to Position Parts in an Ultrasonic Cleaner

Correct parts positioning in an ultrasonic cleaner is as important as the ultrasonic cleaning frequency and ultrasonic cleaning solution formulation.  Yet of these three criteria improper parts positioning is often the cause of unsatisfactory results or extended time in the cleaning solution.

Don’t Fight Cavitation

Better said, don’t impede cavitation action.  Cleaning is accomplished by the violent implosion of minute bubbles created in the cleaning solution by ultrasonic transducers.   The cleaning action occurs on all surfaces wetted by the solution as sound waves migrate upward through the solution from the bottom of the ultrasonic cleaner tank and reflect back down from the solution surface. This suggests that putting too much product in the cleaning baskets is not a good idea because it will impede sound reflection.  At Tovatech we recommend a 1 to 2 inch space between the tank walls and parts in the basket.

Related to this, strive to … Read the rest