Garden Railway Forum

Hello All, I wonder if anyone can help me please? I want to make a safety valve similar to the old Roundhouse 'Pop' or 'Rasberry' type. I believe the diameters of counterbores and dimensions within are critical for the correct working of quick pressure release, and immediate closing. Archangel use them extensively, I believe. Thanks

I've experimented with pop type safety valves and there seem to be three main factors in getting them to work reliably with the minimum of hysteresis at the required operating pressure.

They are the ball diameter to steam hole ratio, the depth of the shoulder and the rate of the spring. The last is the trickiest to get right.

I'll try and post a drawing of the designs I have made. I must confess that I still struggle to make one so that it operates well. Good luck and be prepared to experiment.

Hello Garden Steamer,

Thanks for that. I look forward to seeing the drawing.

What has instigated this is a R/House Vor which wastes an awful amount of steam from about 10 psi onwards until blows off properly at 40psi.

Best Wishes,

Gareth

I'm struggling to post the pdf - all I get is a load of gibberish when I try to upload it. I'll have to ask how it should be done

GardenSteamer wrote:I'm struggling to post the pdf

A common problem with MyFreeforums.

As long as your file is smaller than the upload limit of 2Mb try changing it's name to something simple.

Chris Cairns.

Here's hoping Chris's advice works

Click to download file

It did!

Thanks for that, will have to get machining. Gareth