Some say that you can not tee into a high pressure line. I believe you can, using common knowledge that high pressure is generated when the flow meets a resistance, like a 3ph valve at max, or a cyl fully extended or retracted. If you have a tee in the circuit, and the 3ph is closed, normally the relief would relieve the pressure, say at 2500 psi. Now, let's say that an aux valve has been teed in and operates a cylinder. If you operate the teed in valve and the 3ph at the same time, then the pressure will build up as the cyl is activated to lift a load. If the pressure exceeds the the 2500 , that relief valve will go off until the pressure is relieved. There might be a reason to tee into a high pressure line for simplicity sake. A gate valve in each leg, would simplify this as you would turn the gate valve to shut off one leg of the tee. So, it can be done, but only do it with caution. If you operate one valve at a time, the fluid will go through the path of least resistance, which will be the other valve. You could get by without the gate valves if you use common sense, and that is if the 3ph is up, then the flow will be forced through the aux valve and then you can use that valve to operate whatever.
Off course, any valve upstream will take all or most of the fluid first. Any fluid left over from the upstream valve can be used by the other circuits, no matter how small a flow.
This is only meant to stimulate thought, and not to confuse. Think about it and decide for your self. I know some of you do stuff, that you will not tell anybody else to do. It might work well for you , and not for others that do not fully understand.
If anyone can prove that it will not work, I will delete the post., and apologize for my ignorance.
Correct me if I am wrong, and I know you all will do just that.
