Adding a Hydraulic Pressure Gauge?

[v8dave]

</font><font color="blueclass=small">( Be careful, gauge needs to be hooked up with proper lines and fittings. A high pressure hydraulic fluid leak could penetrate your skin. Use steel lines and fittings intended for the pressure. )</font>

Oops, this isn't a complete thought/idea. What I left out was: if you are trying to mount something in the dash board. You might be tempted to use copper because it is easier to form, but if you plan on using rigid hydraulic lines, use steel.

Excuse the bumbling........

 

[tomrscott]

v8dave,

Good advice for anyone who might be reading the posting, but yes I am very aware of the pressure limits of different fittings. I've spent quite a bit of time looking at hydraulic fitting specs.

I might use steel tubing, or at least 1/8" hydraulic hose rated to 4kpsi or better.

Still mulling over what I want to do with a gauge. I guess my biggest interest is wanting to know what kind of peak loads my hydraulic system sees. If anything does go wrong, I guess the engineer in me would like to know what pressures are happening. I guess the loader is the most critical, and the system might see pretty big transient loads from things like a heavy load being carried and bouncing. Maybe a boxblade hitting a rock could see a pretty big thump too. The more I think about it, the more I think I want to rig a resettable "peak hold" circuit with a pilot check valve. I could put a ball valve in series with the check valve to release it, or maybe an electrically operated pilot check valve.

Still thinking about it.

 

[Trackintrail]

I was wondering if you guys had any input on Using the gauge to estimate the weight you are lifting? how sensitive is valve adjustment and temperature to this pressure here? Lets say I am lifting 1500lbs, and I am reading 500psi on my gauge, If I hook this up to a different forklift and try to use the same readings, will it be different because the valves are adjusted differently? Would I have to recalibrate my weight to PSI comparrisons? Also, how much does temperature affect this.

Thanks.

 

[SPYDERLK]

v8dave,

Good advice for anyone who might be reading the posting, but yes I am very aware of the pressure limits of different fittings. I've spent quite a bit of time looking at hydraulic fitting specs.

I might use steel tubing, or at least 1/8" hydraulic hose rated to 4kpsi or better.

Still mulling over what I want to do with a gauge. I guess my biggest interest is wanting to know what kind of peak loads my hydraulic system sees. If anything does go wrong, I guess the engineer in me would like to know what pressures are happening. I guess the loader is the most critical, and the system might see pretty big transient loads from things like a heavy load being carried and bouncing. Maybe a boxblade hitting a rock could see a pretty big thump too. The more I think about it, the more I think I want to rig a resettable "peak hold" circuit with a pilot check valve. I could put a ball valve in series with the check valve to release it, or maybe an electrically operated pilot check valve.

Still thinking about it.

Do not put a gauge in the loader lines after the valve. It will see a lot of transient loading as you move and it will fatigue the Bourdon tube over a fairly short time. The gauge will probably blow before this tho because of the very high [as much as 10kpsi] transients seen as you move with a full bucket or push hard into a pile with the valve centered. The relief valve is not in this part of the circuit. The bucket will fall if the gauge blows.
I put a gauge in my pump output line as you are thinking about. At the connection to the hose feeding the gauge I threaded the interior of the connector and forced a set screw in lightly. The oil must travel thru the thread helix so flow is very slow. This way if the gauge or hose blows it will only drip. I find that my loader valve builds near 1000psi before opening the lines to feed the loader so everything takes at least 1kpsi. The heavier loader loads give a reading more in proportion to the weight of the load.

Its good because a gauge in this location always gives you a reading of how much pressure the pump is working against no matter what part of the hyd circuit you are using.
larry

 

[AKKAMAAN]

I was wondering if you guys had any input on Using the gauge to estimate the weight you are lifting? how sensitive is valve adjustment and temperature to this pressure here? Lets say I am lifting 1500lbs, and I am reading 500psi on my gauge, If I hook this up to a different forklift and try to use the same readings, will it be different because the valves are adjusted differently? Would I have to recalibrate my weight to PSI comparrisons? Also, how much does temperature affect this.

Thanks.

Hello All!

I'm new to this site and I like it a lot with all the versatility and knowledge available.

I think you can add a gauge between valve and cylinder...SPYDERLK is making an important point though....so put a three way valve b4 gauge to shut it off when not reading...(3rd way drain gauge to tank)....

another way to try is putt'n an very small restrictor about 1.0mm with a 0.8-0.9mm wire loose in the hole for self cleaning, that will keep high energy shocks away from the gauge, but still allows you to read load-pressure....