Hydraulic schematic standards

[draftsmandon]

Hey everyone, I'm new to this forum and fairly new to hydraulic engineering. I'm educated in fluid power mechanics from my engineering technology degree, but far from an expert. Our company has decided to switch to totally ISO symbols on all schematics and I wanted to get some advice and insight from the experts. 1) Do you apply hydraulic schematic symbols to every system including fuel and engine water systems? 2) Our company builds nitrogen pumping equipment, do you apply hydraulic schematic symbols to every process or use piping schematic symbols for piping work? 3) How do you represent objects such as engines and large triplex pumps for which there is no specific ISO symbol?

 

[budt]

draftsmandon:

Presently, Hydraulic symbols are usually done according to International Standards Organization standars ISO 1210-1 and -2 that can be downloaded from their web site. In te Sates we have symbols offered by the Americam National Standards Institue (ANSI). These symbols are almost a carbon copy of the ISO set now.

In actual practice you will find a Hodge-Podge of almost anything from accurate to dreamed up offerings since the Mechanical Engineer is usually considered the one responsible for Hydraulic and Pneumatic system design and implementation. The problem is and has been the training an ME receives in anything Fluid Power is almost non-existent so schematics, when you can find one, are usually of no benefit.

I've been on numerous Trouble Shooting calls and often find there is either no shematic for a circuit or it is so out of date that it is of no help. Often wind up drawing a schematic that matches the circuit so it can be studued to see what is causing the problem.

After saying all that I have come up with a set of symbols I call "Frequently Used Symbols" and have a lot of the odd ones I've come across over the years, plus what the ISO set shows. I also put a simple pictorial drawing/cutaway next to the symbol to help those who have little training identify the piece of hardware.

You can see these symbols in Ch.4 of a basic Fluid Power training book I use to teach classes at:

http://www.hydraulicspneumatics.com/200/eBooks/

Bud Trinkel, Fluid Power Consultant
HYDRA-PNEU CONSULTING

 

[draftsmandon]

Thanks Bud. Your answer represents what I've already seen in other companies, I was curious to see what others have done. Previously our company had either a drawing of the pump itself, or only represented the components with a square and the port labels. It worked fine for the guys assembling the equipment, but had no value for troubleshooting. In our efforts to improve, and use only ISO symbols, we quickly discover that there are no symbols to adaquately represent some major components. For example, if you have a fuel system schematic making a connection to an engine, do most people show a simple engine symbol representing a generic but understandable connection to an engine or would you show a detailed connection to the exact type of fuel pump or filter on the engine? My guess is, it is more understandable without being overly complex to show the generic connection to an engine and let that communicate the idea rather than try to examine exactly what the engine manufacturer designed. From there the exact connection including fittings and locations can be shown in a detailed installation drawing or hose routing drawing.

Thanks for your input, I appreciate the link to the website. We have ordered ISO-1210 and expect to get it in soon. I would appreciate any other comments or critiques as well.

 

[budt]

"For example, if you have a fuel system schematic making a connection to an engine, do most people show a simple engine symbol representing a generic but understandable connection to an engine or would you show a detailed connection to the exact type of fuel pump or filter on the engine? My guess is, it is more understandable without being overly complex to show the generic connection to an engine and let that communicate the idea rather than try to examine exactly what the engine manufacturer designed."

That would be my understanding since all engines may not have the same connecting point location. Symbols are usually very generic and show function not installation. In the case of Engine to Pump Drive, they only indicate what the driving force is and its Direction of Rotation, and is not meant to be a detail of how components physsically connect.


Bud Trinkel, Fluid Power Consultant
HYDRA-PNEU CONSULTING