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The element

BLT transducers — dual frequency

A dual-frequency element is one bolt-clamped Langevin transducer built with two resonances rather than one. The generator switches between them — a coarse note to break the deposit, a fine note to clear what it loosens — in the same tank, on the same parts, off the same array.

If the work is all one kind of soil on one kind of substrate, buy the right single frequency instead. Dual is for a tank that has to do two jobs.

Sold as elements — for building transducer plates, for OEM machines, and for re-elementing a tank whose bonded array has gone deaf. Quoted with the dual-frequency VarioSonic G4 that drives them.

The elements

Five pairings

The first number does the work; the second does the finish. Choose the split by the deposit you are breaking and by what the surface will still tolerate on the second pass. All five are sourced against a firm order — power per element and dimensions are fixed at quotation, against the plate or vessel they are going into.

Dual-frequency ultrasonic transducer element, 25/45 kHz25 / 45 kHz · to orderThe heaviest split. 25 kHz to break scale, hard carbon and weld deposit; 45 kHz to clear what it loosens without chewing the surface.Enquire →Dual-frequency ultrasonic transducer element, 28/68 kHz28 / 68 kHz · to orderWorkshop to finish in one tank — 28 kHz for the deposit, 68 kHz for the finish pass.Enquire →Dual-frequency ultrasonic transducer element, 40/80 kHz40 / 80 kHz · to orderGeneral engineering with a fine second pass. The pairing we are asked for most.Enquire →Dual-frequency ultrasonic transducer element, 40/130 kHz40 / 130 kHz · to orderThe widest useful split: general work at 40 kHz, sub-micron particulate at 130 kHz.Enquire →Dual-frequency ultrasonic transducer element, 80/130 kHz80 / 130 kHz · to orderBoth fine. For work that will not take 40 kHz at all — plated, polished and coated surfaces.Enquire →

Element count, spacing and bonding are specified against the plate or the vessel. Dimensions, mounting detail and power per element are confirmed at quotation. Renders of the dual elements are being produced — the cards above are placeholders, not the part.

Specification

The five pairings

PairingCoarse noteFine noteWhat it is for
25/45 kHz25 kHz45 kHzScale, hard carbon and weld deposit, then a clearing pass
28/68 kHz28 kHz68 kHzHeavy deposit and a finish pass without moving the part
40/80 kHz40 kHz80 kHzGeneral engineering, then fine particulate off the surface
40/130 kHz40 kHz130 kHzGeneral work, then sub-micron particulate
80/130 kHz80 kHz130 kHzDelicate and coated surfaces only, two levels of fine

All five are bolt-clamped Langevin elements built with two resonances: a piezo stack clamped between a front and back mass, tuned so the assembly has a usable mode at each of the two frequencies. Power is the rating of a single element — a plate or an immersible box carries several, and the total is set by the tank.

We do not publish a power or a dimension against these until the element is specified. Dual elements are sourced against a firm order, and the generator is quoted with them — a dual element on a single-frequency drive only ever runs on one of its two notes.

One note only? The single-frequency elements run 28, 40, 68, 80 and 130 kHz, four of them off the shelf.

Only after a generator? Read this firstOpen

We do not sell a generator on its own to drive transducers we have not specified, and we do not sell transducers to run on a generator we did not supply. It is not a policy about paperwork — the two are tuned to each other, and an unmatched pair usually means no cavitation, a drive running hot, and both halves replaced inside a year.

There is no warranty on an unmatched pair. If you already own one half, tell us what it is and roughly when it went in and we will tell you where you stand before you spend anything.

Why that is — the five things that have to line up →

Pairing

What drives them

Dual elements run on a dual-frequency VarioSonic G4 — the drive has to track two resonances and hold a recipe for each, which a single-frequency generator does not do. They do not run on the rod-resonator SonoDrive G5, and a rod does not run on a G4.

VarioSonic G4 generatorNine models · 800 to 1,500 W · single or dual frequencyPick a model → Immersible transducersThe same elements, sealed into a box built to your tankSpecify a box →
How it is sold

The generator and the transducer are bought together

A generator is tuned to the transducers it drives. Four things have to line up: the frequency the generator tracks, the total capacitance of the array wired to it, the impedance and phase that array presents once it is in the liquid, and the voltage across the group under load. We specify all four against each other, so the pair is quoted, built and commissioned as one item.

What goes wrong when they are not matched

The label is not the loadTwo transducers both marked 40 kHz are not the same electrical load — they differ in capacitance, in phase, and in how the assembly moves. A generator is tuned to a particular array, not to a number on a plate.
The tuning is inside the generatorA matching network — transformer ratio and a tuning inductance — cancels that array's capacitance so the drive sees a near-resistive load at resonance. Change the array and the power goes into heat and reactive current instead of cavitation.
Tracking only has a windowThe generator hunts for resonance within a narrow band around its design frequency. A stack outside that window is never found: the drive sits off resonance, runs hot, and trips or limits.
Power has to match both waysOverdriven, the ceramic depoles and the bond lines and the radiating face fail years early. Underdriven, there is no useful cavitation at all — a bath that looks like it is running and does not clean.
The cable counts tooCable capacitance sits inside the tuned circuit, which is why the length is quoted with the set and should not be extended on site.

A new generator will not rescue an old set. Transducers age — output falls away, the resonant point drifts and the impedance climbs — so an older array is no longer the load a new drive was tuned for. A set of mixed ages is worse again: the weakest element pulls the rest off tune and the drive spends its power hunting for a resonance that has moved. What you get is a generator running hot or dropping out, a bath cleaning unevenly, and transducers failing earlier than they should — and from the outside there is no way to tell which end is at fault, so you end up replacing both anyway.

There is no warranty on an unmatched pair. Equipment warranty covers a generator and transducers supplied and matched by Misonics. A Misonics transducer driven by a generator we did not supply, or a Misonics generator fitted to transducers we have not specified, is not covered — we have no way to characterise the combination, so we will not stand behind it. If you already own one half, tell us what it is and roughly when it went in, and we will tell you where you stand before you spend anything.

Enquire about dual-frequency elements

Tell us the pairing you want, how many elements, and what they are going into — a plate you are building, an OEM machine, or a repair. If you are not sure of the pairing, tell us the deposit and the substrate and we will pick it.

Questions

Dual frequency, answered briefly

What is a dual-frequency transducer?
One bolt-clamped Langevin element built with two resonances instead of one. The generator drives whichever is selected, so the same array runs a coarse note to break the deposit and a fine note to clear what it loosens — in the same tank, on the same parts, without moving anything.
Is it one element or two sets?
One. Two separate arrays in one tank is a different and far more expensive build, and it is rarely the right answer. A dual element occupies the same footprint on the plate or the box face as a single.
Can I run a dual element on a single-frequency generator?
It will run on one of the two notes, if that drive happens to track that band, and you have paid for a capability you cannot use. It is also an unmatched pair, so there is no warranty on it. Dual elements are quoted with a dual-frequency VarioSonic G4.
Do I switch mid-cycle or between batches?
Either. Usual practice is a coarse pass to lift the deposit, then a fine pass to clear the particulate before the part comes out. The G4 holds both as recipes so the operator does not set it each time.
Which pairing should I choose?
By the deposit you are breaking and by what the surface will still tolerate on the second pass. 25/45 for scale and hard carbon. 28/68 for heavy workshop soil with a finish pass. 40/80 for general engineering. 40/130 where the second pass has to take sub-micron particulate off. 80/130 where the part will not take 40 kHz at all.
Can dual elements go in an immersible box or a transducer plate?
Yes, both. The box or plate is specified against the array — count, spacing and bonding pattern — not the other way round. Tell us the vessel and what you are cleaning and we will work out the array.
Do they cost more than single frequency?
Yes, on both halves — the element and the generator. It is worth it when one tank has to do two jobs. It is not worth it when the work is all one kind of soil on one kind of substrate; buy the right single frequency instead.
Are they held in stock?
No. Dual elements are sourced against a firm order with a lead time. Power per element, dimensions, stud thread and cable length are fixed at quotation against the plate or vessel they are going into.