Hydraulic Circuit Diagram With Explanation Pdf Free Download !LINK!
Doreen Collicott
Below are some common illustrations of equipment located on fluids circuit diagrams, followed by descriptions of the most common elements. Later in this article series we will describe some simple hydraulic and pneumatic circuits composed of these circuit elements.
The first is to conduct a visual inspection of the hydraulic system, checking all the obvious warning signs that could cause the problem in question (never overlook the obvious). The second is to ask for a circuit diagram for the hydraulic system.
A graphical circuit diagram is a road map of the hydraulic system, and to a technician skilled in reading and interpreting them, it is a valuable aid in identifying possible causes of a problem. This can save time and money in a troubleshooting situation.
If a circuit diagram is not available, the technician must trace the hydraulic circuit and identify its components in order to isolate possible causes of the problem. This can be a time-consuming process, depending on the complexity of the system.
In the case of a mass-produced machine, the hydraulic circuit diagram should be available from the equipment manufacturer on request. If the machine is custom-built, it may be necessary to have the circuit drawn from scratch.
Having an electronic copy makes it easy to update the drawing if the circuit is modified at any time. And always ensure that you are issued circuit diagrams for any additional hydraulic machines you acquire. The nominal cost involved could save you a lot of money in the long run.
Hydraulics schematic symbols are a basic component of hydraulic circuit. Symbols for hydraulic systems are for functional interpretation and comprise one or more function symbols.Hydraulic symbols are neither dimensioned nor specified for any particular position.
Recently our internal hydraulics group was informed that Creo Schematics 2.0 will be the new tool for creating hydraulic schematics. Unfortunately I have little experience with this software but I am very familiar with other PTC products such as Pro-E wildfire 4 and now Creo 2.0. Does anyone in the PTC community have some on how to make hydraulic schematics in Creo 2.0 without purchasing the symbol library offering from virtual interconnect? Specifically I am looking for help on the following topics:
Cutaway Diagrams show the internal construction of hydraulic components and their flow paths. Because these diagrams typically use colors, shades or patterns in the lines and passages, they are very effective at illustrating different flow and pressure conditions.
To a hydraulic technician skilled in reading and interpreting them, a graphical circuit diagram or schematic is a valuable aid in identifying possible causes of a problem. And this can save a lot of time and money in a hydraulic troubleshooting situation.
If a hydraulic schematic diagram is not available, the technician must manually trace the actual, physical circuit and identify its components in order to isolate possible causes of the problem. This can be a time consuming process, depending on the complexity of the hydraulic system.
Electronic-hydraulic analogies are the representation of electronic circuits by hydraulic circuits. Since electric current is invisible and the processes in play in electronics are often difficult to demonstrate, the various electronic components are represented by hydraulic equivalents. Electricity (as well as heat) was originally understood to be a kind of fluid, and the names of certain electric quantities (such as current) are derived from hydraulic equivalents.
In the version with pressure induced by gravity, large tanks of water are held up high, or are filled to differing water levels, and the potential energy of the water head is the pressure source. This is reminiscent of electrical diagrams with an up arrow pointing to +V, grounded pins that otherwise are not shown connecting to anything, and so on. This has the advantage of associating electric potential with gravitational potential.
A second paradigm is a completely enclosed version with pumps providing pressure only and no gravity. This is reminiscent of a circuit diagram with a voltage source shown and the wires actually completing a circuit. This paradigm is further discussed below.
Other paradigms highlight the similarities between equations governing the flow of fluid and the flow of charge. Flow and pressure variables can be calculated in both steady and transient fluid flow situations with the use of the hydraulic ohm analogy.[3][4] Hydraulic ohms are the units of hydraulic impedance, which is defined as the ratio of pressure to volume flow rate. The pressure and volume flow variables are treated as phasors in this definition, so possess a phase as well as magnitude.[5]
A relatively wide hose completely filled with water is equivalent to a conducting wire. A rigidly mounted pipe is equivalent to a trace on a circuit board. When comparing to a trace or wire, the hose or pipe should be thought of as having semi-permanent caps on the ends. Connecting one end of a wire to a circuit is equivalent to un-capping one end of the hose and attaching it to another. With few exceptions (such as a high-voltage power source), a wire with only one end attached to a circuit will do nothing; the hose remains capped on the free end, and thus adds nothing to the circuit.
A capacitor is equivalent to a tank with one connection at each end and a rubber sheet dividing the tank in two lengthwise[7] (a hydraulic accumulator). When water is forced into one pipe, equal water is simultaneously forced out of the other pipe, yet no water can penetrate the rubber diaphragm. Energy is stored by the stretching of the rubber. As more current flows "through" the capacitor, the back-pressure (voltage) becomes greater, thus current "leads" voltage in a capacitor. As the back-pressure from the stretched rubber approaches the applied pressure, the current becomes less and less. Thus capacitors "filter out" constant pressure differences and slowly varying, low-frequency pressure differences, while allowing rapid changes in pressure to pass through.
An inductor is equivalent to a rotary vane pump with a heavy rotor placed in the current. The mass of the rotor and the surface area of the vanes restricts the water's ability to rapidly change its rate of flow (current) through the pump due to the effects of inertia, but, given time, a constant flowing stream will pass mostly unimpeded through the pump, as the rotor turns at the same speed as the water flow. The mass of the rotor and the surface area of its vanes are analogous to inductance, and friction between its axle and the axle bearings corresponds to the resistance that accompanies any non-superconducting inductor.
An alternative inductor model is simply a long pipe, perhaps coiled into a spiral for convenience. This fluid-inertia device is used in real life as an essential component of a hydraulic ram. The inertia of the water flowing through the pipe produces the inductance effect; inductors "filter out" rapid changes in flow, while allowing slow variations in current to be passed through. The drag imposed by the walls of the pipe is somewhat analogous to parasitic resistance. In either model, the pressure difference (voltage) across the device must be present before the current will start moving, thus in inductors, voltage "leads" current. As the current increases, approaching the limits imposed by its own internal friction and of the current that the rest of the circuit can provide, the pressure drop across the device becomes lower and lower.
Higher-frequency AC and transmission lines is somewhat equivalent to sound being transmitted through the water pipes, though this does not properly mirror the cyclical reversal of alternating electric current. As described, the fluid flow conveys pressure fluctuations, but fluids do not reverse at high rates in hydraulic systems, which the above "low frequency" entry does accurately describe. A better concept (if sound waves are to be the phenomenon) is that of direct current with high-frequency "ripple" superimposed.
Fields (Maxwell equations, inductance): Electrons can push or pull other distant electrons via their fields, while water molecules experience forces only from direct contact with other molecules. For this reason, waves in water travel at the speed of sound, but waves in a sea of charge will travel much faster as the forces from one electron are applied to many distant electrons and not to only the neighbors in direct contact. In a hydraulic transmission line, the energy flows as mechanical waves through the water, but in an electric transmission line the energy flows as fields in the space surrounding the wires, and does not flow inside the metal. Also, an accelerating electron will drag its neighbors along while attracting them, both because of magnetic forces.
Leaking pipes: The electric charge of an electrical circuit and its elements is usually almost equal to zero, hence it is (almost) constant. This is formalized in Kirchhoff's current law, which does not have an analogy to hydraulic systems, where the amount of the liquid is not usually constant. Even with incompressible liquid the system may contain such elements as pistons and open pools, so the volume of liquid contained in a part of the system can change. For this reason, continuing electric currents require closed loops rather than hydraulics' open source/sink resembling spigots and buckets.
Quantum mechanics: Solid conductors and insulators contain charges at more than one discrete level of atomic orbit energy, while the water in one region of a pipe can only have a single value of pressure. For this reason there is no hydraulic explanation for such things as a battery's charge pumping ability, a diode's depletion layer and voltage drop, solar cell functions, Peltier effect, etc., however equivalent devices can be designed which exhibit similar responses, although some of the mechanisms would only serve to regulate the flow curves rather than to contribute to the component's primary function.
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