Portable Xray / Electromagnetic Radiation / Forums

Forums

4hv.org :: Forums :: Electromagnetic Radiation

« Previous topic | Next topic »

Portable Xray

1 2 3 4 next

Move Thread

LAN_403

Japex92

Thu Jan 06 2011, 02:33AM

Registered Member #3334 Joined: Tue Oct 19 2010, 02:24AM
Location: Colombia
Posts: 17

Hi,

This is Jairo PÃ©rez from Colombia, I am trying to design a portable X-ray unit for dental applications, I have seem many devices that reach 70 KVp but I am not sure how they get it. It looks like they use a powerfull source based on high frecuency conversion, i am wondering if you know how is that. I have used a flyback to obtain high voltages; however, this options is a bit too old.

Any ideas?

Adam Munich

Thu Jan 06 2011, 02:45AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

Heh, I am actually in the process of making a portable x-ray myself. This is what I plan on doing.

1294281915 2893 FT105404 New Bitmap Image 2

Japex92

Thu Jan 06 2011, 05:00AM

Registered Member #3334 Joined: Tue Oct 19 2010, 02:24AM
Location: Colombia
Posts: 17

Hi Grenadier,

I have used something similar; I set two flybacks, the primaries in parallel and the secondary in series, obviously with their respective ZVS drivers using four MOSFET transistors, but It looks like It has not reach the necessary voltage to shoot electrons from the catode to the anode.

Have you tested your design?, I can provide you the components I used and we can share experiences. Please check our design.

Thanks,

Dr. ISOTOP

Thu Jan 06 2011, 05:47AM

Registered Member #2919 Joined: Fri Jun 11 2010, 06:30PM
Location: Cambridge, MA
Posts: 652

The easiest way to achieve the necessary voltages is with an AC high voltage source and a multiplier.
Series-connected flybacks is risky; the secondaries might be damaged by overvoltage.
Perhaps a 12KV NST and a 4-stage multiplier? That should give you 69KV peak and ~7 mA current.

Proud Mary

Thu Jan 06 2011, 09:57AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Hello Jairo PÃ©rez,

a portable dental X-ray machine must have "type approval" and conform to national safety standards for use on human beings, so you will have to design your product around the 'type approval' criteria and national standards of Colombia.

In practice, 'type approval' criteria are much the same from one country to another, and you should examine machines currently authorised for use in Colombia to see how the designers have approached the problem of meeting type approval standards and safety standards.

Type Approval and safety certification examinations by government agencies are always very expensive, and can involve submitting a number of machines for examination.

Here is a Type Approval application form from India, which must stand in for many like it from other nations:

China is the present market leader in lightweight portable dental X-ray equipment, and is able to offer machines at such low prices it would be hard to find a way to compete with them:

Notice that the mounting type specified for Canadian sales is different "Ball- 2009140* Spiral (excluding Canada longituba)" - clearly to meet a Canadian Type Approval criterion.

Trust me, you will, thankfully, never get Type Approval for a portable dental X-ray machine made out of scrap,

Stella

Adam Munich

Thu Jan 06 2011, 11:27AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

I haven't built it yet because I'm still waiting for the voltage multiplier parts from china, and I'm still looking for an AC FBT.

Japex92

Fri Jan 07 2011, 04:21AM

Registered Member #3334 Joined: Tue Oct 19 2010, 02:24AM
Location: Colombia
Posts: 17

Hi,

Well, I realized that using flybacks is not a good option few months ago; however, it is a good way to start designing and understanding the principles of high frecuency techniques, I have been through legal procedures because we have a 510k FDA approval. Once, I bought UHV-11A capacitors (1000pF@50kVp) and some fast diodes but this solution is not very effective, I did import the lightweight portable dental X-ray equipment you mentioned; but it is not really portable beacuse it is composed by a mainframe and a head:

the weight is nearly 11 kg.
I know that Medium-frequency generators, CW multipliers and Constant potential generators are commonly used in these applications; but I do not know how to start.

I contacted some chinese FBT manufacturers but it seems they do not know much about customized designs;nonetheless, there is an american company that manufactures power supplies like: HVP080 and XRS050N200, have a look at them, the problem is that these devices cost over 1800 USD each. Do you think buying one of these will help?.

Help, help!!!

BR,

Adam Munich

Fri Jan 07 2011, 04:51AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

Just so you know, HV power supplies like that are usually just a flyback and a CW multiplier.

Info on multipliers >

How will you power this? If you choose a battery expect it to be bulky/possibly heavy.

Proud Mary

Fri Jan 07 2011, 09:09AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

You should look at the construction - and any patents - for The Aribex Nomad Pro Handheld intraoral dental X-ray Unit which has a 60kV/2.5mA source, weighs 2.5kg, looks much like a handheld XRF analyser, and costs US$6,495:

Japex92

Fri Jan 07 2011, 07:49PM

Registered Member #3334 Joined: Tue Oct 19 2010, 02:24AM
Location: Colombia
Posts: 17

What do think about the XRS050N200?

1 2 3 4 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob