Schrader Valve - Male NPT Fitting

[CWAnthony]

Hi folks, I'm looking for a fitting with a schrader valve on one end, and a male NPT threaded section on the other end (most common seems to be a 1/8" NPT). There is a hex section in the middle. Does anyone know of anywhere in the UK that supplies these kinds of fittings? I am in the UK and can only seem to find them on US sites, either only Americans use them or I'm looking in all the wrong places.

Thanks in advance

 

[IceStationZebra]

I can't help you with a source, but I have seen larger than 1/8" NPT used on large Agricultural wheels. I think the main reason is that it facilitates filling with liquid ballast.

ISZ

 

[Oldhydroman]

Can you be a little more specific - are you looking for something for tyre inflation or are you looking for something to charge an accumulator? Both use Schrader valves but the pressure ratings are very different.

DOL

 

[CWAnthony]

Thanks for the replies guys. It will be used to charge an accumulator, any idea on the pressure ratings of the more heavy duty ones?

 

[hydtools]

Here are two UK distributors:

http://www.schraderinternational.com/distributors

and high pressure valves:

http://www.schraderinternational.com/Products/Valves/NA-High-Pressure-Valves-and-Connectors

Ted

 

[hydromarine]

You can get charging kits from the makers of accumlators i.e christie, and best to follow the instruction to the book in the wrong hands accumalators can be lethal, all available in the uk

 

[Oldhydroman]

I couldn't get Ted's link to work (maybe the NA bit refers to North America and outside of there the link fails). Anyway, try:

http://www.schraderinternational.com/Products/Valves/EU-Screw-On-Hexagonal-Valves

You might, however, find that you would have to satisfy yourself with a valve that someone else has had designed for them and which they buy thousands of every month. Be sure to tell them the pressure you want to work at - you almost certainly want a high pressure version.

BUT... if you are making or modifying a pressure vessel in the UK (or Europe) you need to be very careful that you are satisfying the requirements of the Pressure Equipment Directive.

DOL

 

[kcj]

Do you need NPT? oring seal is the common connection and easier to seal. Parker sells them separately. We move the accumulator stem schrader valve to a remote manifold block, I just don't have the parker number available here to me.

kcj

 

[CWAnthony]

Hi all,

Thanks for all the links and suggestions. I have been casually persuing this over the past couple of months with not much luck. Schrader can supply valves that will do the job perfectly, but require a minimum order quantity of 500 or £100 (I only need 5 of them!).

McMaster-Carr supply these also, but apparently will not ship to the UK.

kcj, it does not have to be NPT at all, O-ring sealing would also do the job. All I need is a male thread, preferably around the same diameter as the schrader threaded section (this is not critical, though). I don't suppose you know whether Parker still sells the valves you mentioned and would be able to dig out a part number? Or even if you could point me in the right direction as to which section of their website I may be able to find them in, I've been scouring quite a few of their catalogues with not much luck. I'd be very grateful.

Thanks,

Chris

 

[kcj]

I checked our accumulator dwgs and we don't have a separate Parker number for the stem, we just move it from the purchased accumulator to the remote manifold.
It is a -04 or -05, or possibly -06 SAE o-ring boss male thread though.

Check with the closest Parker accumualtor rebuild shop, or if you are in the UK, maybe Hydac or some of the German suppliers would be easier to obtain.

I would definitely go with ORB not NPT. Although NPT is stronger mechanically in some small sizes, because of sealing issues I am not aware of any accumulator mfr using NPT on the gas side. NPT is available on the oil port, but the buyer should be slapped for ordering it.....

Parker probably buys from schrader or someone, in bags of 1000.

Anyway, sorry I have no parker info, the website is really tough to use.
Check a local accumulator rebuild shop.

 

[Oldhydroman]

If you could bear for the gas connection to be 1/4" BSP (with a 60 degree internal cone) then there is a part readiliy available from Olaer Fawcett Christie (now also part of Parker). Go to

http://www.fchdirect.co.uk

and search for part 10031-S03 or 10053-S03. These are gas valves for hydracushions and standard bladder accumulators. There's a photograph so you can see what you will get.

If you definately wanted the 0.302x32 tpi thread (the same as used on tyre valve stems) then you could phone up and see if you can still get hold of part number 10051-S03. This part doesn't appear on the FCHdirect website but it's a valid spare part which is still listed on the hydracushion datasheet.

You need to check in detail but I believe these valves have a 1/4" BSP male thread with an O ring at the base and they seal into a 1/4" BSP female threaded port which has been machined so there is a flat bottom to the port for the O ring to press against. If you can't get any joy directly then ask FCH for a drawing of the part which carries the gas valve in assembly 10010. This assembly consists of a length of tube, some adaptors and a KR type Tee - the assembly is used to connect a back-up-bottle to a transfer barrier accumulator and also build in the gas valve. The details of how the gas valve is built in will give you the information you need to configure your part to suit the gas valve.

DOL