SYLLABUS FOR THE HYDRAULIC MAINTENANCE COURSE
BASIC HYDRAULICS: The characteristics of liquids in pumps and pipes. How a single hydraulic mechanism functions. The advantages of hydraulics as used in industry. Introduction to circuitry.
HYDRAULIC FLUIDS: The principle purposes of the hydraulic fluid in the system. How oil should be maintained including the quality requirements of oil.
HYDRAULIC PIPING AND SEALING: The discussion on piping and sealing embodies the 'plumbing' to carry the fluid from the reservoir to the actuators and the types of connections used. The selection of flexible hoses and the construction of hoses. Cleanliness of the system and how the pipes are to be treated before installation.
RESERVOIRS AND FLUID CONDITIONS: The construction of the reservoir; the use of the reservoir as a fluid conditioner and the installation of filters and where filters should be installed.
HYDRAULIC ACTUATORS: Different types of actuators i.e. types of cylinders used, cylinder construction, cylinder mountings, Hydraulic motors - vane, gear, piston, balance and unbalanced.
DIRECTIONAL CONTROL VALVES: Different types of directional control valves i.e. linear, rotary, poppet, ball etc. What type of valve should be used, fault finding and how the size of the valve should be determined.
PRESSURE CONTROLS: The purpose of the relief valve. Relief valves as venting valves. Unloading valves, sequencing valves and counter balance valves.
VOLUME CONTROLS: Why volume control valves are used. How energy can be saved by the correct selection of valves in relation to the pump flow.
HYDRAULIC PUMPS: The types of pumps used on the high pressure side; non-positive displacement pumps as replenishing pumps, feeding the high pressure pumps.
ACCESSORIES: The various accessories used to perform functions in the hydraulic system; accumulators, intensifiers, pressure switches and instruments.
INDUSTRIAL HYDRAULIC CIRCUITRY AND FAULT FINDING: Having discussed symbology throughout the course, we now give each student a chance to read a wide selection of industrial circuits. We also simulate fault on the circuits and the student is asked where he would start to trace the faults. We also show the student how to logically work his way through a circuit to trace a fault and not to start stripping machinery until he is reasonably sure that he has found the point or place at which the fault has occurred.
SYLLABUS FOR THE ADVANCED HYDRAULICS COURSE:
This course will follow the sub-headings as listed for the Hydraulic Maintenance Course, but the various items will be discussed in very much more detail, as to where these units would be used in a system. A system will be designed from the stage where a load is given and the speed at which we would want the cylinder to move. From this information the size of the cylinder will be calculated. The speed of the operation will let us determine the capacity of the pump and the power required to drive the pump at the pressure and flow required and then we will determine pipe sizes. A 'high-low' system will be designed, using a double pump to obtain a fast approach at high volume and low pressure; then changing over automatically to a low speed and high pressure. Alternative methods to obtain a fast approach will be taught. We will discuss accumulators; how to determine the size by calculation and then design a system using the accumulator. Time will be spent on hydrostatic drives; i.e. open circuits and also closed circuits, and different methods of decelerating.
CIRCUITRY DESIGN: Systems will be designed in detail from single cylinder, single valve applications with manual operations, progressing to single valve with remote pilot, single cycle applications initially. The circuitry will become progressively more complex with multiple cylinder systems single cycling, continuos cycling and methods to unload the pump within the rest condition.
Decompression circuitry is discussed and demonstrated with circuitry. Regeneration circuitry is discussed which makes use of extra oil transferred by the cylinder to the pump flow for high speed approaches. Standard hydraulic symbols are used throughout the course.
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