Hydraulic circuit symbol explanation

[Music] [Applause] [Music] so this is an introduction to hydraulic symbols we will talk you through this basic hydraulic circuit just to give you an introduction to what the symbols do what they are our symbols are based on ISO 1219 parts 1 & 2 there is now an international agreed standard on hydraulic symbols it's taken many years and still obviously certain manufacturers have always been using different symbols so it's going to take a long time to change and harmonize everything together so the watchword is be very cautious symbols I've seen lots of circuits that have been drawn incorrectly now there are different symbols for the same thing so make sure your circuit is correct I would strongly recommend the very first thing you do with your hydraulic circuit is go around and look at every component and take the part number off the label and write it down write a list of all the components and if you've got a parts list check it make sure they are all correct the label data is probably the best information you've got are the only real definite information on which valves or components you've got not all the information is shown in the symbols and as I say lots are wrong or different so um but let's just talk you through this power unit or hydraulic system circuits so we will start with our reservoir or our tank that will be the same one as this tank here the white at leakage comes in to and from that tank we've got some hard rigid pipe coming into our pump this is a fixed displacement pump driven by an electric motor so it's drawing our fluid from the reservoir pushing it through initially through a hydraulic hose and we need that to isolate the vibration from the system these dots are very important they show connections convention is it should be that use the dots on all connections but not the bridges I know a lot of people like to put bridges across lines but that can be confused if you photocopy a number of times it can turn into a blob and look as though you've got a connection so keep the same with whatever you're doing but that's a consistency that's now within the standards here's our relief valve safety relief valve to protect if anything goes wrong it's blocked in this circuit saves our pump exploding just puts the flow back to tank we then come into moving in this direction we come into our filter clean the fluid up which is very important and we've got a bypass so at cold temperatures possibly when the filters blocked the fluid will come around the side of it now at that point your indicators should show with a light and a gauge here to show that the filters blocked and it needs changing we've got a reducing valve shown here probably don't really need it but it's nice so you can see the difference here reducing valve pilot senses the downstream whereas this one's sorry upstream this one senses downstream so that's the relief this is the reducing valve both adjustable spring adjustable now you can see the position of the arrow is slightly different as well so because it's a fixed displacement pump we need an open center valve so that when nothing's happening there's no pressure the flow is just coming back through the tank and being kept clean we like that and here's our valve main directional valve so this has got three positions so we switch from this position when you switch one way imagine these symbols move into the middle position and the flow goes Peter B and a to T or this way switch other way it goes Peter way Peter T so sorry directional valve which controls the flow into our cylinder control for direction and these valves control the flow there meter outs on the way and it comes through the check valve which is a cylinder up and on the meter outside it can't go through the check valve so it comes through the flow control valve and that controls the speed raising and lowering so that's a basic introduction gives you an idea what all the symbols do and how they all work together look at the the rest of the course got a lot more detail a lot more explanation on the variations but as I say there's a lot of them not just incorrect drawings but the a lot of the detail is not given in all of these symbols if we if we just take a look at a flow control over here this is pressure compensator we can tell whether it's an arrow that's a pressure compensated valve so that's the simplified symbol makes our drawings a bit easier to get onto the paper a bit clearer but actually when you expand it that's really what's happening so um you know there's a lot more detail and more valves inside the one valve but we don't always show them back to this and also that's the same with all circuits the designers don't want to give away all their details all their technical knowledge and their IP particularly with mobile equipment you'll be lucky to find a mobile circuit a lot of manufacturers so they can be very secretive so you won't have all the information you'll have very simplified circuits but at the end of the day it's still the best way to understand a system in to diagnose any faults so our surface very very important you

Channel: Engineering Adventures

Views: 88,766

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Keywords: Hydraulic, hydraulics, fluid power, hydraulic pumps, pumps, engineering, training, hydraulic symbols

Id: WLmcj0c5JAQ

Length: 6min 6sec (366 seconds)

Published: Thu Nov 09 2017