Posts by Rachel Kohn
Setting Ultrasonic Cleaner Power, Frequency and Time
In addition to using the correct temperature and cleaning solution formulation, achieving optimum results in an ultrasonic cleaning operation calls for a correct “blend” of ultrasonic power, ultrasonic frequency and cleaning time. Absent a proven recipe the three ingredients often are established through experimentation using ultrasonic cleaners that provide the flexibility to vary power, frequency and time.
Indeed, it may turn out that a fixed frequency and fixed power setting do not deliver the desired results. Adjustable power and adjustable frequencies may be the key to optimized cleaning action thereby reducing the time needed to complete jobs and improve operation efficiency.
A Brief Brief on Ultrasonic Power and Frequency
Power in this post is defined as the electrical energy in watts per gallon of cleaning solution delivered to the transducers that provide cavitation action in the cleaner. More power generally means faster cleaning but only to a point, beyond which … Read the rest
Sonic Cleaning Solves 3D Printing Mold Support Challenge
3D printing, also called fused deposition modeling and fused filament fabrication, has revolutionized and lowered the cost of traditional molding techniques such as the lost wax process. By using two moldable thermoplastic formulations such as ABS for the part itself and PLA for removable mold supports 3-D printing is capable of quickly producing highly complex configurations.
A key to the efficiency of the process is fast, safe removal of the PLA mold support without risking damage to the ABS part. An ultrasonic cleaner is proven far faster, safer and more effective than water sprays or manual scrubbing.
3-D Printing in Brief
Computer aided design files for components are programmed into the 3D printer which uses thermoplastic filaments to create components by successively building up extremely thin layers of plastic. The ABS filament ends up as the product; the PLA filament, deposited at the same time, serves as a support for … Read the rest
Understanding the 3 Rs + L of an Analytical Balance
Selecting the correct analytical balance for precise weighing is not an easy task. We’ve covered several key points in previous posts but it’s always a good idea to provide a refresher course – especially as it relates to terminology that is sometimes confusing yet important. In this case it’s the 3 Rs: readout, repeatability and reproducibility plus linearity.
We also provide hints on applying these criteria to selecting a lab scale.
R #1: What’s readout? Also called readability it’s what you can read on the scale’s display panel. Simple enough but in terms of specification you’ll have to decide on what you require in terms of the smallest difference displayed when weighing. Usually its 0.1 milligram but in the case of a semi-micro balance it may be 0.01 mg.
R #2: Repeatability is the ability of a balance to display the same result when an object is repeatedly placed … Read the rest
Selecting a Moisture Analyzer Drying Process
Infrared moisture analyzers such as the new Kern MLS-C now available from Tovatech use the thermogravimetric drying process to calculate the moisture content of a sample. Also called the loss of weight on drying (LOD) method, the drying process compares the weight of a sample after drying to the weight before drying. The difference is displayed the percent of moisture in the sample. This is a critical quality control step to confirm that commercial bulk drying ovens are performing to specification and that the product meets regulatory or industry standards for moisture content.
Selecting the Moisture Balance Drying Mode
Because products react differently to heat employed during the drying process, laboratory moisture balances can be programmed for different drying modes or drying profiles. These can be classified as standard, rapid, step and gentle. The mode is graphically displayed on the control panel. Here is a general description of each:
- Standard
Tips on Mixing an Ultrasonic Cleaning Solution
Mixing an ultrasonic cleaning solution is simply a matter of following instructions. While it may be politically incorrect we refer to the common cliché “real men don’t read instructions” to introduce our point: There are many benefits to be gained by preparing an ultrasonic cleaning solution according to instructions.
Ultrasonic cleaning solution manufacturers such as Elma, represented by Tovatech, spend a significant amount of time developing instructions on preparing recommended dilutions and cleaning procedures for their line of liquid cleaning solution concentrates and powders. As an example, elma tec clean A4, a widely used demulsifying formulation for labs and workshops, is to be diluted to 2 to 5 percent with water in the ultrasonic bath. Whip out your calculator and figure out how many liters of cleaning solution can be prepared with a standard 2.5 liter container of biodegradable elma tec clean A4 concentrate.
Well golly, you might think (that … Read the rest
Two Approaches to Ultrasonic Degreasing
Ultrasonic cleaning is an excellent method to remove grease and other oily deposits on newly fabricated and refurbished metal parts. Two types of ultrasonic cleaning solutions – emulsifying and demulsifying (or non- emulsifying) – are commonly used for removing such deposits. Let’s look at these two options.
Emulsifying cleaning solutions collect oily contaminants in a mixture or an emulsion of the water-based cleaning solution and the oil. While cleaning is initially thorough continued operation of the cleaning bath causes a build-up of contaminants in the solution. This eventually reduces cleaning effectiveness.
Moreover, when products are removed from the bath they may carry this contamination into the rinsing cycle. Because of this carry out it is important that the parts are thoroughly rinsed to remove remaining emulsified oil. More than one rinsing cycle may be required.
Elma clean 210 is an example of an emulsifying cleaner that is a good choice … Read the rest
Why Moisture Content Matters
Moisture content, as we have pointed out in many of our posts, is important for a variety of reasons, many of which have to do with quality control, product shelf life and fair pricing. Controlling moisture content can occur at several points along the processing line and usually involves the use of drying ovens, some of which are equipped with moisture sensing devices to reduce the percentage of moisture to target levels. Moisture levels are set by industry and trade associations, and by government agencies. It is up to manufacturers to verify moisture content.
Picking up on our opening sentence, an example of moisture’s effect on quality is exemplified by products as basic as sugar, table salt and bagged cement. All three are hygroscopic – exhibiting a tendency to absorb moisture. A target moisture standard for sugar is 11.9%, … Read the rest
Mechanical Motion and Ultrasonic Cleaning Efficiency
Ultrasonic cleaners are used in applications as diverse as jewelry shops, hospital central service supply departments, auto repair shops and PCB repair. They are preferred over manual scrubbing with brushes and solvents because of their thorough cleaning action and ability to reach surfaces inaccessible by any other cleaning method. Biodegradable ultrasonic cleaning solutions are also more environmentally friendly than aerosol sprays and solvents.
The contaminant-removing power of ultrasonic cavitation – the implosion of millions of minute bubbles against surfaces being cleaned – can be substantially improved by introducing two mechanical means called oscillation (also known as agitation) and rotation to the cleaning cycle. We’ll look at these two techniques separately although in some equipment they can be combined.
What is Oscillation?
Our friends at Wikipedia define oscillation as “the repetitive variation, typically in time, of some measure about a central value (often a point of equilibrium) … Read the rest
Scale with Remote Display Gives 0.1g Resolution
The separate weighing platform of the new ILS 50K and companion ILS 30K, 50 kg and 30 kg capacity industrial scales, each with 0.1 g resolution and a 5 g minimum load, makes these laboratory balances ideal quality control instruments for accurately weighing heavy toxic, odor-emitting or contaminated samples under fume hoods or in glove bags. The rugged stainless steel weighing platform handles compact high-density samples such as drilled cores and sawed beams of concrete, and is connected to the control and display unit by a cable approximately 1 meter long.
Now available from Tovatech, these lab scales are offered with external calibration (the ILS configuration using a separately purchased 30 or 50 kg weight) or with automatic internal calibration (the ILJ configuration). ILJ models will re-calibrate every 3 hours or when there is a temperature change of 3⁰C or more.… Read the rest
How to Store Hepatitis Vaccine
Proper refrigerated storage of hepatitis vaccines is essential to maintain potency as well as to avoid substantial monetary losses due to lack of potency and the time and inconvenience to revaccinate patients. Proper vaccine storage is also required for providers participating in the Adult Hepatitis Vaccine Project, which is equivalent to the Vaccines for Children program. AHVP compliance is necessary for providers participating in the project and receiving state-supplied vaccines.
Step 1: Calculate Vaccine Storage Requirements
Healthcare providers should calculate the number of hepatitis vaccines they will store in their refrigerator. This is done by adding the number of public and private vaccines on hand from the last order and multiplying that number by 1.25 to determine total doses. Using the table below match this number with the minimum cubic feet required for storage.
|
Maximum doses | Minimum cubic feet |
|
1000-2000 |
40 |
