interpretation pressure regulator symbols

[biesseautomazioni]

Good morning, I have some problems correctly interpreting pressure regulation symbols as attached.
some have a single arrow other the double arrow others present the discharge. I would like to ask for help to understand the differences between these symbols

 

[DoctorBomber90]

I'm trying to give you an answer. those with the discharge (white triangle) should be used in the tire while, if the triangles are black, then it is oleodynamic/hydraulic (passing a liquid, then you have to provide a recirculation tank). the valve in the first image (the darkest one) doesn't drive me crazy (I'm sure it's right?). because, generally, the valve positions represented in the hydraulic/pneumatic circuit should be in the normal position (or rest), that is, without the intervention of the fluid force, the valve works in that position.

 

[biesseautomazioni]

I'm trying to give you an answer. those with the discharge (white triangle) should be used in the tire while, if the triangles are black, then it is oleodynamic/hydraulic (passing a liquid, then you have to provide a recirculation tank). the valve in the first image (the darkest one) doesn't drive me crazy (I'm sure it's right?). because, generally, the valve positions represented in the hydraulic/pneumatic circuit should be in the normal position (or rest), that is, without the intervention of the fluid force, the valve works in that position.

Thank you for the answer... I try to see if the source where I took them is reliable. Could you give me some tips because some images have the central arrow indicating the direction of the single or double fluid? I initially thought that you had the double arrow when there is the drain (the triangle you mentioned in the answer) but there is an image that presents the drain triangle but despite this it has a single and not double arrow.
Thank you.

 

[DoctorBomber90]

we start from the simplest valves (the ones with one arrow).the pressure limiter is a normally closed valve that opens from the moment when the fluid pressure is such as to counter the sealing force of the spring (usually they are located immediately after the compressor/pump so as to avoid reaching too high pressures and therefore carry out a safety task).
the pressure reducer/seque valve is a normally open valve that only closes when the downstream pressure of the same valve is such as to overcome the force of the spring that keeps the valve open.

 

[DoctorBomber90]

the valve with the double arrow can work both from limiter and from reducer (depending on how the fluid crosses it).as it was drawn by me, if the fluid comes from above is a pressure limiter, otherwise it is a pressure reducer.
generally, if there is double arrow, it means that the fluid can cross the valve in both directions.

Thank you for the answer... I try to see if the source where I took them is reliable. Could you give me some tips because some images have the central arrow indicating the direction of the single or double fluid? I initially thought you had the double arrow when there is the drain (the triangle you mentioned in the answer) but there is an image that presents the drain triangle but despite this has a single and not double arrow.Thank you.

the leftmost valve of the image "simboli2" is a 3/2 valve (i.e. 3 doors and 2 positions) which, in case the downstream pressure is such as to counter the force of the spring, opens and tends to download the fluid (in the case of oil in a tank or if it were air...for air).
look at the drawing "scheme" that I represented you on the right of the image posted in this answer.
You will notice that, if the pressure force of the fluid prevails over the force of the spring, then the valve will have the position of the "inclined" arrow that corresponds to the discharge of the fluid.
Let me know if you understand.

 

[Kaji]

for symbols this seems quite complete

 

[biesseautomazioni]

now it is clear... thank you very much to all