Memory Pressure Gauge? 2

[slickstyles5]

Hi,

I am looking for the hydraulic symbol of a memory pressure gauge? This gauge is a mechanical gauge, if possible, that keeps in memory the highest pressure attained in the hydraulic fluid line. It could be digital if a mechanical one doesn't exist. Can someone direct me to a manufacturer where I could obtain the symbol for my hydraulic schematic?

Thank you in advace.

Gabriel Leblanc

 

[btrueblood]

A check valve oriented towards the pressure gage, and manual (vent) valve between the check valve and the gage.

 

[unclesyd]

I've looked at several gauge companies that I'm familiar with and none still carry the type gauge mentioned in the OP.
Looking further all I could find were the "lazy hand' low pressure gauges. Checked with a friend who works on fuel injection systems for cars who at one time had this type gauge on his test stand, no joy he has upgraded to a recording digital. Checked my old work area where I used a pressure gauge with a lazy hand to make high pressure rupture disks, it's gone though the 16" Heise gauge is still on the wall.
Check two hydraulic system hand books, nothing. Searched the symbol library of two cad systems, again no joy. I'm in the process of asking a gentleman who's news letter on hydraulics I get quite often about your OP.
As you know pressure gauges on hydraulic systems are tolerated until you need one for diagnostics

 

[slickstyles5]

btrueblood - That's an excellent idea, I didn't think of that!! Thanks a lot!!

unclesyd - Thanks for all this research, please keep me posted if you find anything. Read below ...

Update to OP : Apparently, the gauge would have two needles, one that would give the live pressure reading, and one that would stay at the max pressure attained until it is reset.

 

[unclesyd]

This type gauge is still popular in lower pressure ranges, say up to 200 psig, but it looks like the are few and far between at any higher pressure. One problem is that this gauge has so many names like the Lazy Hand, peak pressure, and so on.
The peak holding hand is not connected to the pressure measuring part of the gauge. It is really part of the face plate of the gauge. There is a bushing in the face plate and the shaft of the peak indicating hand comes through the bushing and has a small nob on it, where after the pressure indicating part of the gauge pushes the peak hand to the indicated pressure it stays there until reset manually.
A word of advice this type gauge doesn't like fluctuating pressures.
If you have to have one I think any gauge shop could make one by modifying an existing gauge.

 

[JR97]

galeblanc,

We recently (within the last year) purchased Weksler analog pressure gages that have a maximum pressure indicating hand. We use them to determine the maximum pressure needed to operate door assemblies. They work fine and we have not had any reliability issues during re-calibration.

Their website is

http://www.weksler-gauges.com.

They have pressures from 15 to 10,000 psig available. The maximum pressure pointer is an option. The website is a bit clunky. To see the options you need to click on the blank options space in the "how to order" section.

JR97

 

[unclesyd]

JR97,
I tried to look at the Weksler gauges on the Aschroft site where the Weksler line section is under contruction, no information.
You bring up some good information where the addition of a lazy hand might be an option, since it's not part of the pressure measuring components, when ordering other brands.

 

[Compositepro]

The "maximum pointer" is an optional accessory for most Ashcroft pressure gauges, and I assume many other brands as well.

 

[btrueblood]

Gabriel,

Just remember if you use that technique, to add the cracking pressure of the check valve to the value on the gage (i.e. there is a minimum pressure drop to lift the check valve off its seat, and thus the pressure recorded by the gage is reduced from the actual peak pressure upstream of the check). If the vent valve is hooked in parallel (around the check valve), the resultant gage has the functionality, although quite a vit klugier, than the two-needle gages that unclesyd is talking about. You'd leave the vent closed, record peak pressure, then rotate the valve open to read current line pressure...etc.)

All of the mechanical devices suffer from response time lag, i.e. they may not record actual peak pressures if the event is short enough (e.g. water-hammer "spikes"). In automotive compression testers, this effect is compensated for by measuring over several cycles, and assuming the peak is eventually reached.

 

[JR97]

unclesyd,

Weksler site seems to be working today. Here is specific web address for ordering page for a 4" analog gage.

http://weksler-gauges.com/CatPages2005/P012_RoyalMonel.pdf

JR97

 

[unclesyd]

JR97,

Thanks,

I went back the route when I looked at the Ashcroft site and to get to that information one has to download a complete catalogue under the Weksler banner.
It looks like Ashcroft has two sites or you can't get there from here.

http://www.ashcroftinc.com/

http://www.ashcroft.com/

We now have to ask the OP did we answer the question or just confuse them.

 

[slickstyles5]

Hey,
Nope everything is clear in terms of what I needed. I determined that it was a lazy gauge that I needed. The only issue may be to actually find one but when the time comes I'll speak to one of my suppliers and have him work for me.
Regards,
Gabriel