piston accumulator position transducer

[byrdj]

My google results are not helping me to much on my quest.
I have seen in OEM (Parker) lititure about using an ultrasonic transducer to measure piston position, however I caan not find a make/brand for such a device.

My desire is to measure the piston position over the accumluator's bore for one in a 2000psi fyrquil hydralic system. the evioroment will be severe and I need at least 5 year expected life.

I have seen the position monitioring that use an LVDT rod attached to the piston with the core sliding through where the gas charging valve would have been...this will not work since I do not have the space available.

I could also use a transducer that attached magnet to piston and used external hall effect transducer

thanks

 

[desertfox]

hi byrdj

We use this type for cylinder piston position:-

http://www.balluff.com/Balluff/us/ProductsChannel/Overview/en/Micropulse+Transducers.htm

Here is a typical manual for one:-

http://www.balluff.com/Balluff/Documents/manuals/868142_EN.pdf

desertfox

 

[byrdj]

I would concider, but could not visualize how to make it work. (unless the magnet could go on the piston and the sensor tube be on the outside. This is an example of the accumulator I have. they are about 10" diamater and from 4 to 10' long

 

[desertfox]

Hi byrdj

Ah I see your problem, we have rod type pistons and we hollow out the piston rod with a blind hole so that the probe inserts into it and as you say we attach the magnet to the piston to register travel.

I'll dig around and see if I can find something

 

[byrdj]

the reason for this quest is these accumaltors require isolating and draining to check the precharge on a frequent schedule. I'm thinking if I can have a monitor that provides piston position, the charge is conformed without perform a complete charging procedure.

 

[byrdj]

I just recieved a reply from Parker and even though the sensor is in thier litature, they are not aware of an actual device.

 

[btrueblood]

MTS sensors makes pressure-capable magnetostrictive sensors that can measure cylinder/piston position inside a cylinder. You'd probably want to mount it on the centerline of the accumulator, which would mean re-purposing and drilling a new port for the charge valve. You also have to seal the sensor rod where it pierces the piston. But they do work.

 

[byrdj]

I might consider that option, but the current location of the accumulators does not have the availble space.

I just got off the phone with Hydac. Their European catoluge also offers this option. the US engineer was aware, but has never seen this option. hoping they maight be able, but I'm still searching.

 

[byrdj]

followup--just received brochures from HYDAC for their sonic and cable systems. Both of them look like the changes to install will be minimun, sorry no links

 

[hydraulicsman]

http://biem.co.kr/hydac/accumulator technology/piston accumulators.pdf

 

[byrdj]

the figure 1.7.3 is what I had seen in liteture from current accumulator supllier(Parker), but when I asked for details, it was not availaable. However, HYDAC supplied me with information giving details about sensors and processor. Thus it is available in Europe, but it most come with the accumulator.

after sitting down and doing the piston travel calcs for what I would call alarm conditions, using the ultrasonic position switches strapped to the side would provide similair assurance of accumulator health

I have presented this ideal of continous monitoring verses periodical isolate, drain, and check charge to the industry which I work and to date no one else sees the benifit. so I'm not sure If I will have the backing from my current customer to install

 

[EdDanzer]

You may be able to use a transducer by Rota.

http://rota-eng.com/

Ed Danzer

http://www.danzcoinc.com

http://www.dehyds.com