Ultrawave Hygea 1250 Pro ultrasonic cleaner - Frasers latest purchase :)

[Fraser]

 I have been using small consumer grade ultrasonic cleaners for mechanical parts cleaning for years. I occasionally need to clean a PCB as well but would not trust the cheap jewelry cleaners for such a task. I recently decided to add a decent quality ultrasonic cleaning bath to my tools inventory so took a look at prices. For a hobbyist they can be very expensive at round £1000    I could not justify such a cost so took a look at the secondary market.

I have ended up with a professional Ultrawave Hygea 1250 ultrasonic cleaner from a friendly dentist who accepted my offer of £120 for a unit that cost him £1800 new  It has an excellent 8L capacity and enough room for my needs. The basket is a nice 3 tier unit.

It does have a fault though. The unit is an approved product for cleaning medical tools and has various process monitoring including temperature. If the temperature goes above a pre-set level, the unit reports an over temperature alarm. This is important in the health related deployments as temperatures above 40C cook protein onto the item being cleaned !

I am hoping for a relatively simple cause of this overheating but will need to investigate further when time permits. Ultrasonic cleaners are relatively simple beasts but professional units like the Hygea use top grade transducers and drivers. Cheap Chinese units can be lacking in this respect and become unreliable. Temperature control is normally pretty simple and reliable. It may be that my unit has a failed sensor or driver circuit causing it to keep the heater on.

Well to the pictures .........

[Fraser]

Behind the front panel......

A PIC18F6680 at its heart

[Fraser]

Hygea 1250 brochure

[Fraser]

Chipset list

PIC18F6680 Micro-controller
DS1302 RTC
HIN232 RS232 transceiver
CA3140 OP-AMP
ULN2803 Darlington array
Winstar Wiel2 DC-AC backlight inverter
APS CP-205 Printer module

Fraser

[Fraser]

I will be using a quality cleaning fluid in the Hygea. My fluid of choice is an Allendale product designed for PCB cleaning.

 http://www.pcb-soldering.co.uk/flux-remover-ultrasonic-solution-5-litre.html

£20 for 5L and it is mixed in the ratio 1:10 so makes 50 Litres of cleaning fluid 

Fraser

[wraper]

It does have a fault though. The unit is an approved product for cleaning medical tools and has various process monitoring including temperature. If the temperature goes above a pre-set level, the unit reports an over temperature alarm. This is important in the health related deployments as temperatures above 40C cook protein onto the item being cleaned !

I am hoping for a relatively simple cause of this overheating but will need to investigate further when time permits. Ultrasonic cleaners are relatively simple beasts but professional units like the Hygea use top grade transducers and drivers. Cheap Chinese units can be lacking in this respect and become unreliable. Temperature control is normally pretty simple and reliable. It may be that my unit has a failed sensor or driver circuit causing it to keep the heater on.

Don't know if this is a fault, even without any heater, ultrasonic cleaners heat up the water very significantly if left running for longer time just by ultrasonic transducer. So it would need built in cooler, otherwise there is no way to keep it cool. I'd say, run it for 20 minutes and most of the cleaners will reach 40+^oC unless there are tons of water to heat up.

[wraper]

I will be using a quality cleaning fluid in the Hygea. My fluid of choice is an Allendale product designed for PCB cleaning.

 http://www.pcb-soldering.co.uk/flux-remover-ultrasonic-solution-5-litre.html

£20 for 5L and it is mixed in the ratio 1:10 so makes 50 Litres of cleaning fluid 

Fraser

I'm  wondering, does it clean only water-soluble fluxes or any type?

[Fraser]

Hi Wrapper,

Good points and well noted.

The self heating is detailed in the manual. 10C to 15C per hour. The unit is a fully programmable beast and the normal cleaning cycle is 10 minutes long. If it detects the temperature rising above the preset high limit the unit cancels the cleaning process and advises the user in a printed warning and alarm sounder. In normal use the manufacturer warns to not use the unit for expended periods of time if a high temperature is to be avoided. the machine can cope with higher temperatures and I believe it is capable of heating to +60C but that is tool high for medical use. My use is not so critical. There is no active cooling in the unit to maintain a set temperature, only the control over the PTC heater pads as you will see in the pictures I will upload in a minute.

The dentist who owned it, knew the machine well so I suspect something has changed to make him believe a fault exists. Presumably he knew about the self heating aspect of ultrasonic cleaners after years of use ? I will be testing the unit with cold water to initiate its automatic degassing and heating of the water to the correct temperature. User error is always a possibility to be excluded.

I have inspected the  main units now and will upload the pictures. It is quite an interesting design and more complex than the simple Chinese units I have worked on.

Fraser

[Samogon]

Hygea 1250 brochure

Nothing said about operating frequency and if it sweeping or not.

[Fraser]

OK, time to see inside the bottom section of the unit where the work happens 

The modules and transducers seem decent quality but I am disappointed with the quality of the cable management. Maybe it is because i m used to seeing cables properly laced together but the cables in this unit looks dis-organised and messy. I will address this when the unit is confirmed fully working.

Description of what is shown in the pictures.......


240V mains enters the unit at the rear. It is dual gang switched and fed to a EMI filter. The filter feeds power to the rear mounted "LCDpanPS" PCB.

The "LCDpanPS" PCB contains several relays, a transformer and regulators. It looks well made. There are low voltage and high voltage interfaces on the PCB. The high voltage outputs provide power to the High Frequency generator, the heater and the fan. Each has its own output port. The low voltage ports connect to two cables that go to the front panel PCB in the lid. Pin identities have yet to be established. One pair of low voltage pins were easily traced and found to power the MagLoc that holds the lid closed during operation. I will likely disable that for my usage.

The heater comprises two PTC heating pads mounted on the front side of the fluid tank. They share a common neutral feed but their live feeds are slightly different. One goes directly to a bimetallic over temperature protection device mounted on the bottom of the fluid tank, whilst the other connects to the same point, but via a small blue 'pill' shaped device mounted on its pad surface. Why both pads do not have this 'pill' device I  am not sure yet. I suspect it is another temperature control device but need to investigate further. The bi-metallic safety cut-out is fed with 240V from the "LCDpanPSU" and I would expect this to be a straight forward relay controlled heater feed.

The temperature sensor is a small 2 wire device attached to the right side of the tank (viewed from the front). Its wires connect to one of the cables gong to the front panel PCB. The type of temperature sensor has yet to be established.

A water presence sensor is also present in the side wall of the fluid tank (yellow wire).

Now to the High Frequency generator that drives the 4, yes FOUR, piezoelectric transducers. The HF generator is fed with 240V from the "LCDpanPSU" PCB, presumably under the control of one of the relays on that board. The output drive for the transducers is a pair of wires that feed to all four transducers connected in parallel. The drive line is marked "HF" on the PCB. The HF PCB itself is shrouded in  a 'rain-coat' so was not closely inspected. it contains a large heat-sink with power transistors mounted on it, and a large HF transformer to drive the transducers at high voltage.
There is a single thin blue wire connecting the HF generator to the front panel PCB via one of the multi-core cables that connect to the lid assembly. The function of this cable is not proven but it is one of the following

1. HF generator on/off
2. HF Generator power output control
3. HF Generator frequency control
4. HF Generator operation monitoring by the MCU to identify a fault condition.

The lower unit is equipped with a powerful fan to circulate air around the tank and electronics.

All in all a nice setup, just let down a little by the wiring management, or lack there-of !

I will upload some pictures later. For now, a quick view with the bottom plate removed.

Enjoy the pictures 

Fraser

[wraper]

All in all a nice setup, just let down a little by the wiring management, or lack there-of !

Frankly I don't see on the pictures anything that should be tied together.

[Fraser]

Wraper,

Wait till you see the other pictures ........

Samogon,

I have just taken a picture of the specs.....

Frequency is 30 to 40 kHz into 4 pillar transducers with a modulation of 50 to 100Hz
P-P power output is 500 Watts

The unit is a swept frequency design.

[Fraser]

Here are the pictures I promised......

[Samogon]

Very impressive specifications, i would say it is better than crest  imo

[xrunner]

I just recently bought a new / better one off Ebay, but it ain't a badass unit like that one. I've done a foil test in mine, I'd like to see what a foil test looks like coming out of that thing.

[SeanB]

Blue blob will be a PTC thermistor switch, so that the initial heating is very high power with cvold water, then as it reaches around 30C ( I would guess) the PTC goes very high resistance so limiting the heater power to only one strip, so you have better control of the setpoint with a simple on off control.

Likely the temperature sensor is either cracked or failing, giving either an error in the sensed temperature or the amplifier is giving the wrong reading into the microcontroller. Otherwise the heater relay is stuck on, which is very common on those little relays.

[Fraser]

Hi SeanB,

Excellent observations thank you.

I was wondering about a two stage warm up process but did not think of the 'pill' being another PTC rather than a bi-metallic thermal switch. Thanks.

My first thoughts on hearing about the overheat fault were that the heater control was staying hard on due to a failed TRIAC. At that time I was not aware of the relay switching of the heater rather than an electronic switch. The unit displays the current detected temperature taken from the tank sensor so I should be able to check its accuracy very easily using one of my many thermocouple thermometers. I still think the heater is most likely 'stuck' in the on condition but will test that tomorrow at the same time as testing the built in temperature monitoring accuracy.

Thanks again for the suggestions.

Fraser

[Fraser]

I filled the tank with water for testing today and quickly established that the temperature sensing circuit is the fault rather than the heater controller.

At first the temperature was correctly reading the correct 15C of the tap water. However once the ultrasonics started the reading shot up to over 40C and was very unstable, ranging between 38C and over 50C. The unit understandably announced an over temperature alarm. The water was still only 15C yet the sensor was measuring it at 24C even without the ultrasonics running. Sounds like a damaged sensor to me rather than the readout circuit in the well isolated control panel. I shall investigate further when time permits.

Fraser

[Fraser]

OK an update.

All wiring between the front panel PCB and the sensor was tested and is OK. Sensor reads 107 Ohms at 18C and 111 Ohms at 28C. It is therefore a standard PT100 type 

Once the ultrasonic vibrations start the PT100 goes crazy with a resistance varying around 119 Ohms hence the high readings of around 50C.

A new contact type PT100 sensor will be procured and fitted.

Fraser

[Fraser]

Just ordered a patch format PT100 and some ceramic 2mmx2.3mm mini ceramic PT100's.

The patch is hopefully the best solution as it is self adhesive and good to 100C. The tiny ceramic PT100 sensors might be a pain to attach to the tank and their Platinum coated nickel leads cannot be easily soldered so must be welded or crimped.

The RS 285-661 patch looks perfect for the task though. I got it for £10 inc postage instead of the RS price of around £40 +20% VAT 

http://uk.rs-online.com/web/p/products/285661/?cm_mmc=UK-PPC-_-google-_-3_RS_stock_codes-_-RS%7CPSF_421349%7CPlatinum+Resistance+Temperature+Sensors&mkwid=sZLMMVkTr_dc%7Cpcrid%7C83735527363%7Cpkw%7C285-661%7Cpmt%7Cp%7Cprd%7C&gclid=CM-C1dfuh80CFbYV0wodvWoBkQ

Fraser

[Fraser]

The M222 'chip' PT100 sensors arrived today  I can now test the unit whilst I await the arrival of the better (?) patch sensor.

They came in their own little plastic box....nice packing 

They are a bit of a nightmare sensor though. The size is just 2mm x 2.3mm with 10mm long platinum plated nickel leads. It is not recommended to try soldering to the platinum coated leads. Welding or crimping is suggested most appropriate.

Take a look at the pictures. These things are truly fiddly to work with. I used a UK 5p piece for scale.

I may try my battery tag welder to weld some nickel solder pads to the wires or use my smallest bootlace crimp connector on them.

Fraser

[Fraser]

The new 'patch' type PT100 sensor arrived today. It looks perfect for the task and superior to the original fitment.

Pictures and X-Ray images follow......

[Fraser]

The new PT100 sensor was installed yesterday and the unit has been returned to full operating condition.

The tank heating is nice and quick and the temperature stability during a cycle is good. All functions work as expected and the unit appears very nice indeed. The tank fluid temperature may be set to ambient or up to 60C which is plenty for my needs. The fluid I am using recommends 40C to 70C.

I will carry out an aluminium foil strip test when time permits. This shows the coverage of the Ultrasound and its effectiveness within the tanks area.

I attach the original print out showing the fault, and the print out of a test run yesterday.

Another feature of this tank that I love is the ease with which the fluid may be changed. A valve on the side is opened and all the fluid drains out into your chosen container. And I mean 'All' as the drain and outflow are all lower than the tank base...... it is excellent at draining away the fluid. The user may then fill the tank with new fluid or a different fluid type. No mess and no hassle, as you would expect from a Dental product used in a dental surgery. o be honest though, the manufacturer had to employ such a system as the unit weighs 18.5kg so emptying would otherwise have to be done by syphon or 'cup & sponge' !

Fraser

[Fraser]

I have been listening to the sound the Hygea 1250Vp makes when running. I can report that it sounds like no other ultrasonic cleaner I have used. You can actually hear the sweeping effect rather than the usual regular hiss. It hisses and then goes through a sweep routine up and down its range, followed by another constant hiss, so the microprocessor actually produces a cleaning routine that is a mixture of static and sweeping ultrasonic frequency. Impressive stuff.

I have now removed the controller PCB as I want to better understand its I/O ports. I will be defeating the MagLoc solenoid and the 'lid open' sensors as they are not needed in my application. They are part of the certification for medical use.

Pictures of the controller PCB and X-Rays of it will follow.

Fraser

[Fraser]

Controller PCB images and X-Ray image.