EBME Forums Forums Maintenance Technical Assistance Therapy O2 flowmeters

Hi,
I don't know if there has been a previous thread on the problem with Therapy O2 flowmeters whereby the flow can be significantly reduced by applying slight pressure to the control knob. We found during PPMing that the flow can be reduced by about 5LPM by pushing lightly on the knob. At low flow rates the flow can be stopped completely. We have spoken to Therapy about this but they have not heard of this problem before. They stated that they expect a difference of about 2LPM at a setting of 10LPM due to the play on the thread of the spindle. Has anybody else come across this problem? I will add that the reding on the tube will always be accurate, but any problem will only be noticed if the flowmeter is checked at regular intervals by the user. I don't have any values of how much pressure is required to aheive this condition but have been told that it is very small.

Which flowmeters, e.g. Std/Diamond range, BB? Is this from new or with used flowmeters? Do you think this is a problem with wear or a design/manufacturing issue? I think there's a 4 year performance warranty on Std and 7 year warranty (that covers performance problems/accidental damage, I think) on Diamond range products. Have you discussed this or had any further response from Therapy on this issue?

We're having trouble with the std 15LPM flowmeters. The problem was first noticed with old ones > 4 years old but we checked a new batch and they are the same. Not all flowmeters do this some fall by about 2LPM.

Why arent MHRA being informed of these problems. I've read that such devices conform to ISO and that there is no need to check their accuracy over their lifetime. This indicated that there is need. Doesnt it?

Had the same problem with some non-therapy equipment Ltd flowmeters mounted on a nearly new transport incubator a few weeks ago and have had similar problems on other neonatal ventilator flowmeters in the past - it's not just confined to a single flowmeter or manufacturer. It's down to general design, manufacture, wear and tear - mechanical tolerances I think. Threads wear over time and valve seat clearances need to be adjusted at manufacture.

Well, it’s just a needle valve, after all. I should imagine that all such valves would show the same tendency. It’s a good observation, but does it really matter, I wonder? Is a nurse going to stand there for five minutes with her finger on the button, as it were? She’s far too busy for that, surely?

Put another way.
If its leaking your wasting energy from your plant.
If its leaking into an area were you dont want uncontrolled O2 at a certain time you could have clinical / operational issues.
If its giving more or less than it should do and you are aware of it and do nothing about it are you as Clinical Technologists responsible for any / all consequences of that leak?
If the manufacturer of any device says you should test it at set intervals and you dont, without authorised risk analysis to say why you havent how much are you as a Clinical Technologist responsible for?

Speak to the manufacturer? Sorry, silly question

We usually get a positive response from Therapy - this includes regular visits from our local sales representative to pickup faulty items and check up on any problems - these are usually associated with operator abuse not performance of the equipment. A highly technical response is not required on site if replacement or service-exchange equipment, under the terms of a contract or warranty, can be made available.

Is it possible that problems with manufacturing, i.e. batch problems, were missed on acceptance checks or perhaps operators' are over-tightening the flow valve (possibly damaging threads, the valve-seat, gastight seals or some other component(s)? It's apparent the company is not "shy" about specifications, e.g. Diamond Range Flowmeter , and servicing requirements of its other flowmeters, e.g. Flowmeter Manual since they're available on the website for all to peruse.