tm associates: 3678 Bassett Street Santa Clara, CA 95054 Phn: 408 727 8388 Fax: 408 727 8997 E-Mail: tony@


Ultrasonic Cleaning Systems

Ultrasonic Probes / Meters

 DI Water Systems

Ultrasonic / DI Process


L-2001-4 Ultrasonic Probe

Includes quartz probe [½" dia.]
Includes interface Electronics for computer
Includes Software for your computer
Attaches to USB port
Display Wave form on oscilloscope
Display Frequency on Spectrogram
Display Power Level in RMS, Peak to Peak & Db/watts per cm2
Record all Displays as Files
Transient Recorder for tracking Process
Lap Top computer compatible
Map power levels in tank
Check effect of baskets on work load
Check transducers for operation
Check effects of filtration on ultrasonic power
Check power intensity levels between tanks


Spectral Analysis of Frequency for a 68 kHz tank vs. 170 kHz tank

The tm associates ultrasonic Probe consists of a sensor that is immersed in the liquid of the ultrasonic tank. The sensor senses the energy of the actual cavitation collapse generated by your ultrasonic tank. This energy is translated into a voltage that changes and fluctuates with the amount of energy generated. The voltage is then amplified and displayed a portable computer screen with our L 2001 probe system software. The Model 2001 Ultrasonic probe consist of a sensitive Probe, and an interface box that plugs into the parallel printer port of any computer including a portable or lap top type and the software to display the readings from the probe. It is completely self-powered and no batteries are required.

The L-2001 Software displays the following Information:
A. Wave form; The ultrasonic wave form is displayed on an on screen oscilloscope
B. Frequency; The frequency [Major and secondary] are displayed along with relative power on the Spectrogram screen. A set of cursors may be placed on the screen and a small box will show the relative frequency and strength of that frequency.
C. Power; The voltage meter screen has three windows that will show the RMS of the ultrasonic power, The peak to peak power, and the power expressed in dB/m Watts. All three of the readings are displayed at the same time.
D. Transient Recorder; The transient recorder will allow you to make a continuous record of the power in the tank over a long period of time.
E. The oscilloscope, spectrogram, and power meter readings may be saved as files and recalled and played for later analysis
F. You may display the oscilloscope, spectrogram and voltage meter all at the same time. The transient recorder operates separately.
G. Information on power levels may be imported to a spreadsheet for graphic analysis.
H. Screen shots may be saved as Jpeg files and all files and screen shots can be annotated with on screen comments.
I. All data files may be recalled and placed in comparison mode for comparison to new readings

Spectrum Analysis of different Frequencies 68 kHz & 170 kHz

Transient Recorder Showing Power Intensity Control Increase

Scope Comparing different Wave Forms at different power levels

Digital Meter

Tanks vary widely with frequency and the amount of power per gallon of solution in a tank. The digital meter compensates for a low power to volume ratio or a high frequency vs. low frequency tanks. [Lower frequency will tend to concentrate energy in a band or level with in the liquid. A higher frequency will distribute the power evenly throughout the tank.

A 1/2" diameter quartz probe is included for measuring the power in close quarters around work fixtures. The probe is a .5" dia. sensor for making cavitation measurements over the frequency range of 20 kHz to 2 MHz. It has a high sensitivity relative to its size and is Quartz. It measures the cavitation in a constrained spot.  This is a realistic picture of what your part sees as its cleaned. Special probes are available on a custom basis.


Probes: Note: Probes are available in Quartz or Titanium in 18" or 6" lengths

 Lap top computer with CD, Hard Disk, and Floppy Disk USBt with the software pre installed is available as an option. The computer has a full range of forms, instruction manuals and articles on ultrasonic cleaning. It is pre set up with directory files to help you organize your ultrasonic cleaning systems performance files.

Custom Probes: Probes such as a 4 sensor disk probe for measurement in work holder and Titanium probes for rugged use. Other custom probes available on request.

Probe Holder: A probe holder allows positioning of the probe at any point in the tank for continuos measurement.

Custom 4 sensor probe for Disk Drive substrates or Wafers

Probe Holder

Digital Hand Held Meter for quick measurements

Probe Set in Case

Cleaning Process Certification with the L-2001-4 Ultrasonic probe

Todays requirements for cleaning certification are more difficult to archive. With the L-2001 probe this is no longer a problem. Any ultrasonic or mega sonic cleaning system can be certified with complete records of its performance. You can easily compare the performance of a tank from month to month.

Probe Calibration:

The L-2001 Ultrasonic Probe is calibrated to a known internationaly recognized standard of Joules;

Checking power in an Ultrasonic Tank via Heat rise method is straightforward. An LF or RF generator can be attached to an antenna or a tank. Heat rise, over a defined time, with a set amount of fluid with a fixed density is the determinative value in watts that directly and accurately correlates to power in your ultrasonic tank. As an example 500 wall watts to the generator will generally show between 380/420 generator watts and power measured in the tank itself will be 280-340 watts. All ultrasonic tank and generator systems will absorb watts in the generator circuit and in the conversion and transmission of the power to the fluid in the tank. The common fluid used is DI Water at 18 meg-ohms. [ Note: if other fluids are used compensation must be used to obtain accurate measurements]

The following are Typical results for determining watts in an ultrasonic tank

Note all test are made as follows
Standard ultrasonic tank with known volume of water.
Water in Tank is 17-18 meg Ohm DI
No recirculation in tank
Generator set a full power [if power intensity control is present] [degas tank for 15 min before test]

The chart below shows Watts / Avg. of a 500 Watt Ultrasonic tank with power intensity control where the power has been decreased for each of the 3 measurements [power measured at supply point] and also shows the Watts / Avg. expressed in the tank at the reduced power levels.

   Ambient T/C

      Start T/C

      End T/C

    Mass /H2O

   Elapsed Time

   Watts Avg.

   Wall Watts

22 C

25 C

27 C

24 Kg

600 sec [10 min]



22 C

25 C

26 C

24 Kg

600 sec [10 min]



22 C

25 C

25.5 C

24 Kg

600 sec [10 min]



1cc = 1 g [@ 4deg C] 
L x W x D of water in tank in centimeters / 1000 = Kg 
1 cal raises 1 gram of water 1 deg C [specific heat of water]
1 cal = .00163 Watts 
1 cal = 4.19 Joules
Note: All calculations reference pure [De Ionized]  water

Watt Calculations:

1. Final temperature of tank liquid - Initial temperature of tank liquid = Temperature Rise [Tf]-[TI]= [Tr]
2. Grams of water [Gw] x Tr = Calories of heat added to water by ultrasonic energy [Cus]
3. Work [Joules] is calculated by multiplying Calories by 4.19 Joules [1 calorie =4.19 Joules
4. Power is defined as work over time and is expressed in Watts. Joules /ultrasonic energy divided by time of test in seconds [T] = Watts of ultrasonic energy required to raise temperature of liquid =W/A
Tf-Ti=Tr xGw=Cus x 4.19Jus = Tjus/T = Watts of Ultrasonic Energy expended in working liquid over the test period.

Or more simply:
Temperature rise x # of Calories required to raise water to new temperature x 4.19 divided by the time of the test in seconds = Watts / Avg. of the ultrasonics

Note: the method described above is valid for a static tank factors such as different solvents, detergent or overflows will dramatically affect the amount of ultrasonic power in a tank. The initial calibrations should be made using a standard setup. Future measurements of tank power then can be made using the L-2000 or the L-2001 with complete accuracy.

In addition to the base line certification of an ultrasonic tank in static mode [DI Water Only] Cleaning Process certification can be made by repeating the same test with product in the tank. Using the L-2001 probe with the product in the tank will yield a record of the tanks performance with product.

The following factors will affect the amount of energy in the tank.

1.Temperature of the water: As the temperature increases the efficiency of power expression in the tank increases. This increase may be up to 50 to 60 Watts.

2.Tank Design and Transducer Placement: The thickness, shape and interior design of an ultrasonic tank will have a significant effect on the propagation of ultrasonics within the tank. The attachment method and type of transducer will affect the ultrasonics. Additions such as spargers, overflows, and recirculation filter banks will also affect the ultrasonic propagation. The only way to measure these effects are from within the tank liquid.

3.Addition of detergents: The addition of detergents to the water will change the viscosity of the cleaning solution. This will increase the amount of cavitation in the tank due to the lower energy requirements to form cavitation vacuoles.

4.Filtration of the tank liquid: When and how often the tank has its liquid pumped though a filter will cause a disturbance in the tank liquid and ingress air into the cleaning solution. The ultrasonics must then use some of the energy to 'degas' this solution before the full effect of the ultrasonics is again applied to the cleaning process. The speed of the liquid movement will also affect the ultrasonic action

5.Work holder Design: The design and material of the work holder has an enormous effect on cleaning. Some types of plastics will absorb ultrasonic energy faster than the water. [a simple test is to measure the temperature of the water and the temperature of the plastic, run the tank for a set time and re-measure the temperature difference between the plastic and the water. The plastic will temperature will be higher than the water showing it has absorbed more energy than the water.] Stainless steel open work holders are the best choice, plastic of any type should be avoided.

6.Product type and placement in the tank: Some product will tend to absorb energy more than others. Some product will reflect ultrasonic energy and dependent on placement will cause localized increases in watt density. Placement within the work holder ant placement in the tank will affect the ability of the ultrasonics to reach all areas of the product. At the edges of the ultrasonic tank power will drop due to the placement of the transducers and the stiffing of the diaphragm of the tank bottom.

7.Insertion and removal of product: The speed of insertion and withdrawal of the product can cause ingression of air to the cleaning fluid requiring more time for the tank to recover to full operating power. Care should be taken to determine the best insertion and pullout speeds for the product.

The use of the L-2001 ultrasonic probe will measure all of the above changes and allow the process engineer to optimize the cleaning process.

1 .TM associates standard Meter and Ultrasonic Probe: [L-2000]

A. Originally tm associates supplied meters with complete certification to National and International Units [i.e. volt / ampere / ohm / Hertz] this certification would only apply to these units.

B. The probe and meter measures dB/m a measure of relative sound pressure difference. The certification does not apply to dB/m [this is not a recognized international measurement] even though dB/ is widely recognized and used daily it is not an international recognized unit but as the sound pressure measurement developed by Bell Labs.[ this measurement can be translated into "Watts" [Joules /Second] by setting the correct impedance of the meter for any given frequency. By combining the decibel unit with a suffix to create an absolute unit of electric power [i.e. it can be combined with milliwatt suffix to produce the 'dB/m] Zero dB/m is the power level corresponding to a power of one milliwatt and 1 dB/m is one decibel greater [about 1.259 m/W

C. tm associates probe assemblies are linearized and a ratio of 1: 1000 is used and therefore at an impedance and frequency dB/m is equivalent to watt per cm2. We correlate and calibrate the probe to an absolute recognize "known" and do this over a fixed period of time. The known is the joule and the fixed period of time is seconds and therefore the calibration is to "Watts" when measuring temperature change.

This is the same procedure used to calibrate tanks using the Temperature change method. It is the same method used for RF calibration and is directly traceable to Joule's original determinations.

The absolute measurement is temperature, and we measure the rise in temperature from the monitored power input from the wall [supply] and the generator circuit [ultrasonic power supply] while measuring the temperature range in the bath of DI water [24 liters]

We prequalify the temperature probes [2 K types, Stainless Steel attached to a B&K 715[ NIST calibrated] meter using salt and Ice to verify true "0" degrees C. Then measure over a period of time on a high resolution oscilloscope [self calibrating signal, square wave] set to transient record in milliseconds measurement mode. We match the transient impedance based on frequency to the "heat change based on frequency to the "heat change" watts calculation and then match that to dB/m on the meter and oscilloscope.

We have therefore applied basic heat units and directly applied them to electronic amplitude data at frequency and set our numbers accordingly after five repetitions.

The same procedures are used on our L-2001 ultrasonic probe with self calibrating Oscilloscope software