EE trying to understand hydraulic circuit, I understand the 2-way valves but the rest is a guess.

Energize solenoid A and fluid flows through check-valve on left and out A to actuator. I cannot see how fluid flows out of B circuit? What is that solid black triangle symbol in a rectangle above the check valve?  Is circuit still pressured after de-energizing solenoid A?

This drawing is from Europe.

It would take a lot more time than I care to take to explain the circuit operation and even then a person who is not familiar with Fluid Power Symbols would probably have more questions due to the answer.
 
It is not the way I would do the circuit just to get a Double Acting Actuator to cycle but I don't have all the information the designer had when he chose the components and designed the circuit.

Some of the symbols I have never come across before so a part name, number and manufacturer might be required to identify the items in the enclosure on the left side Chain Line Box that has VOLUME COUNTER WITH INDICATOR unde it.

Generally speaking, Energizing Solenoid A will send oil out the A Port to the atuator and oil from the Actuator will return thru Port B and return to Tank.

Energizing Solenoid B will send oil out the B Port to the atuator and oil from the Actuator will return thru Port A and return to Tank.

The Pmax...Bar writing with arrows pointing to identical symbols are Cross Port Relief valves to protect the actuator from being damaged if some external force tries to move it when setting idle. hey will open at a safe pressure and let oil out of the actuator if an external force is going to move them.

The two valve with the solid black triangle is a hydraulic energy triangle and is indicating the check valve in the box below it is Piloted Open when the actuator is signalled to move, so oil can get back to Tank. Sort of a typical Pilot Operated Check Valve symbol. Not necessarily as ISO would show it but still plain enough for anyone who is used to reading Fluid Power schematics.

The schematic is typical of what I find on machines on a regular basis because very few persons are proficient at drawing schematics. I'm sure ou finwrong symbols on electric schematics also.

If you need to talk thru the rest of it send an email to fluidpower"1 at*hotmail.com (leave out the Quotation marks, spaces and asterisk' and us the @ before sending) and I will send my phone number. I have about got crank calls to less tha one a month and I want to keep it that way.

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