Need help with an Ultrasonic Cleaner - Not working

[mecheng46]

Hello, few weeks ago i bought an ultrasonic cleaner from a local guy with the hope to use it to clean motorbike parts. Initially when i plugged it in although it seemed to be working my parts were coming out of it in the same condition.

I took the bottom cover off it and i noticed that this cleaner had 4 transducers. All 4 had some sort of issues, either cracked, broken off connections etc. I ordered 4 new ones online and glued them in position, same way as the originals.

I switched on the unit and although it does sound that is doing something in reality is not working. This time i also noticed that the stainless body gets really hot in couple of areas, it only take few seconds in operation and these hot spots are appearing in the same places on the external body/housing.

Does anybody have any experience with these cleaners and what the issue might be with it? For info this cleaner is not the cheap type, it's a british made cleaner.

 

[Spoon]

I've never messed with the circuit of one.  Never needed to as it always worked.

What's the make and model?  Someone on here may be able to help.

 

[mecheng46]

thanks Spoon, it's WE ultrasonic cleaner, i have attached couple of pictures of the PCB and the 4 sensors. I had a good look on the PCB and nothing seems to be burnt or damaged. It powers up and it's does make the usual ultrasonic cleaner sound/noise but it don't seem to be doing any cleaning. It also developed two hot spots externally and i can feel a bit of vibration around the two spots.

I never messed with an ultrasonic cleaner, it feels like it's out of sync, either too high or too low frequency if there is such a thing with these cleaners.

When i bought it the 4 ultrasonic sensors were damaged/cracked and with broken connections/loose cables. I spoke to the manufacturer back then but the initial cost to just inspect and quote for to replace the 4 sensors was not worth a go so i decided to fix it in house. There is not much of info on the internet about these cleaners.

Picture 1

Picture 2

 

[Sidewinder]

I would not be sure that you are looking at sensors but more actuators in the 4 units.

That is the “speakers” that create the ultrasound which does the agitation.

You say that you have glued them on.

What “exact” procedure for removal of the old and fitting of the new did you undertake?

What adhesive did you use?

What is the modulus of elasticity for the adhesive in the thickness of application?

What is the frequency of the “sensor”?

What is the frequency response from the adhesive as applied at the operating frequency?

You are looking at micrometer movement of the tank at frequencies above 10kHz probably more.

Very little energy in a “sound” wave at such frequency.

You might well loose that energy in the wrong way with simply incompatible or too much adhesive.

 

[mecheng46]

What “exact” procedure for removal of the old and fitting of the new did you undertake? Old fittings/sensors been pulled out and scrapped. They were glued together with epoxy. The sensors were cracked and damaged. I made 4 new fittings/sensors glued together same as the original ones

What adhesive did you use? JB weld epoxy

What is the frequency of the “sensor”? 44khz

What is the frequency response from the adhesive as applied at the operating frequency? I am not sure on this, i might have to find a frequency meter to get a reading

You might well loose that energy in the wrong way with simply incompatible or too much adhesive. I definitely used a bit more adhesive than the original to glue the fittings on the bottom of the tank. I have a spare set of sensors that i can glue directly on the bottom of the tank to i minimise the loses. I don't know much about these cleaners, i hope the issue is the amount/type of glue on the fittings.....

 

[Sidewinder]

Well, you asked for suggestions and having worked on HF cleaners and worked undertaking vibration analyses of equipment, and designed vibration sensor mountings, I felt like my points were valid.

There is more to glue than epoxy or JB Weld Epoxy.

You may well have an adhesive that resonates at 44kHz.

I would be surprised if JB Weld could tell you.

We used to get this sort of data from our adhesive suppliers when we designed the pickup points to ensure that the frequencies of interest got through.

Very important when you are diagnosing vibration spectra from expensive manufacturing equipment where downtime costs hundreds of thousands of pounds an hour, getting such things right is well worth it.

 

[Sharpend]

Sidey you never cease to amaze me with the knowledge you have, if I had a fraction of it then I’d consider myself blessed.  :Salute

 

[Sidewinder]

Sidey you never cease to amaze me with the knowledge you have, if I had a fraction of it then I’d consider myself blessed.  :Salute

Thank you @Sharpend, unfortunately it doesn’t help when you are dying from cancer!

 

[Sharpend]

Thank you @Sharpend, unfortunately it doesn’t help when you are dying from cancer!

Sadly not, this is when you realise that there is nothing more important than your health and family, it’s just a tragedy that we spend so much time neglecting those in the course of our working life. 

 

[Sidewinder]

Sadly not, this is when you realise that there is nothing more important than your health and family, it’s just a tragedy that we spend so much time neglecting those in the course of our working life. 

Yeah I have realised how much I have missed since my diagnosis at stage 4 towards the end of last September.

Still can’t walk unaided, nor more than a few steps with a frame and an assistant.

 

[mecheng46]

Today i had a conversation with a guy who knows a thing or two about these ultrasonic cleaners and circuits. Apparently due to the minor differences in glue/sensors/cable length and whatever else the system needs fine tuning to give the correct current to the 4 sensors. This guy reckons that there is not enough current reaching the sensors and thus are not giving the right frequency. He suggested to measure the current from the main coil and adjust it accordingly. Some PCB's have a trimmer for this purpose but he is not sure if mine has one or not as i did not have a good picture of my PCB. If this PCB don't have a trimmer switch then i will have to add insulation paper on the main coil to achieve the relevant current value.

There are two trimmers/potensiometers adjacent to the big coil on the PCB but i don't want to mess with them before getting some advice please.

Anybody who can comment on this? Does this process sound familiar to anyone?

Picture 3

Picture 4

If you read through this whole thread you will realise that 99.9% of "Plug in devices" (As opposed to the wiring etc for the socket they plug into) require specialist knowledge, something we do not have. By all means ask, but I doubt you will get the reply you seek.