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Level 3 Pneumatics
How does a regulator in a pneumatic system respond to a decrease of downstream air pressure? - correct answer ✅increases orfice size to increase air flow Which type of directional control valve is an on-off valve in a pneumatic system? - correct answer ✅two-way valve Where should the air intake be located? - correct answer ✅in the coolest place possible what is an air receivers purpose? - correct answer ✅to compensate for fluctuations in demand, and to dampen pulsations. what things must every air receiver have? - correct answer ✅Gauge, drain, and pressure relief valve what must the pressure relief valve be set at? - correct answer ✅must be no higher then the lowest maximum pressure rating of any part in the system.
Level 3 Pneumatics
how should safety relief valves be mounted, and why?
correct answer ✅vertically, usually on top, to prevent dirt and sludge from blocking them. what are the three types of commonly used pipe systems? - correct answer ✅the grid(dead end) system, decentralized system(unit system) and Loop system what is the preferred or recommended piping system?
correct answer ✅the loop system Describe the Grid(dead end) system of piping. - correct answer ✅its the simplest, only requires one compressor, starts with a large diameter supply line that gradually decreases. one drawback is that systems at the end of the circuit could face air starvation when upstream demand is heavy.
Level 3 Pneumatics
correct answer ✅packed bore - o-rings are fixed in grooves in the body through which the spool slides. Packed spool - o-rings are fixed in the spool. The air pressure in a pneumatic tool will determine? - correct answer ✅torque the air flow in a pneumatic tool will determine - correct answer ✅speed what is the function of a venting type regulator? - correct answer ✅allows pressures above regulator setting to be relieved excess flow valve should be installed on air hose larger then? - correct answer ✅1/2" how is pneumatic tubing sized? - correct answer ✅outside diameter
Level 3 Pneumatics
in a 5way/3position valve what are the 3 most common centres? - correct answer ✅pressure centre exhaust centre blocked centre what does the safety relief valve on a air reciever control? - correct answer ✅releases any excessive pressure usually set 5-10% above the systems maximum pressure. where is the drain valve located on a air reciever? - correct answer ✅must be installed on lowest point on receiver. what is the purpose of a fusible plug? - correct answer ✅will melt and release all the pressure in the receiver if the air temp becomes dangerously high. also will ensure the path in which the pressure would vent, wont endanger workers
Level 3 Pneumatics
what type of agent is used in a liquid dehydration process? - correct answer ✅ethylene glycol In a deliquescent dryer, is the flow normally upward or downward through the bed? - correct answer ✅upward what is dew point? - correct answer ✅the temp to which air must be lowered in order for condensation of water vapor to begin. define relative humidity - correct answer ✅a comparison of the amount of water a sample of air holds to the maximum amount it could hold if saturated. Regenerative dryers often use a portion of the dried air for regeneration of the saturated desiccant bed. true or false - correct answer ✅true
Level 3 Pneumatics
what are common desiccants? - correct answer ✅activated alumina, granular and bead type silica gel, and molecular sieves. what are the four categories of air dryers? - correct answer ✅absorption adsorption refrigeration mechanical when working on a dryer system what must you do before performing maitenance? - correct answer ✅depressurize and isolate the complete system. Define regeneration(reactivation) in gas and air dryer systems. - correct answer ✅term used for the process of removing the accumulation of moisture from the dryer bed.
Level 3 Pneumatics
Describe Refrigeration dryers. - correct answer ✅least expensive method of dew point reduction, this is because there are no absorption or absorption materials that require maintenace or replacement. by cooling air in an aftercooler the air is less able to hold moisture, so water can drop out of the stream and be removed. In a Refrigerant circuit in a refrigeration dryer what happens to the water? - correct answer ✅because water freezes at 0C(32F) the condensed water would freeze in this dryer if the controls were set too cool the air too much. This type of dryer is capable of lowering the dew point to 2 to 3 degrees celcius. lower temps would cause it to freeze. Describe Mechanical dryers. - correct answer ✅use only mechanical, physical means to cause moisture to fall out of the air stream. these include devices that use intertia or mechanical components, such as barriers and filters.
Level 3 Pneumatics
Define Liquid seperators - correct answer ✅air enters a large vessel, the reduction in velocity by the size of the dryer and the baffles inside allows contaminants such as sand,oil,acids and other liquids to slow down and drop to the bottom of the vessel where they can be removed Define a Centrifugal Separators - correct answer ✅found downstream of compressor aftercoolers the centrifugal separator uses centrifugal force to throw incoming air or gas outwards causing the heavy particles to drop to the bottom and be removed. what are Demister Pads? - correct answer ✅are a drying device that use fine wire mesh screen or pads. Pads provide a surface for the mist to adhere to until droplets become large enough to run back into the vessle. what are Coalescing filter elements? - correct answer ✅a highly effective means of oil and water removal. designed to remove fluids in the form
Level 3 Pneumatics
zero degrees Rankine is equal too -460F. true or false - correct answer ✅true whats the difference between Pascals law and Bernoullis principle? - correct answer ✅pascals law deals with pressure in a non moving fluid(static), whereas Bernoulli's principle deals with a constant flow of fluid(dynamic). Boyles Law - correct answer ✅states that if temperature remains constant, the volume changes inversely to the pressure. Charles law - correct answer ✅states that if the pressure on a given volume of gas is held constant, the volume changes in direct proportion to the absolute temperature. Gay-Lussac's Law - correct answer ✅states that if the volume is constant, the pressure exerted by the gas is directly proportional to the absolute temperature.
Level 3 Pneumatics
what does FRL stand for? - correct answer ✅Filter,regulator,lubricator filter to clean air and protect downstream components. (such as the regulator) regulator to maintain a set system pressure lubricator to add a mist of oil in the air stream what would happen if a FRL was installed backwards?
correct answer ✅the oil from the lubricator would gum up the regulator and then the filter would remove any oil left in the air before it got to its point of use. air filter - correct answer ✅used to remove harmful contaminants from the air before it reaches the components. regulator - correct answer ✅regulator is used to help reduce line pressure from the compressor.
Level 3 Pneumatics
coil is electrically energized, it creates a magnetic field which pulls the iron plunger into the coil. it causes the valve to move to another position and change flow path. define check valve - correct answer ✅allows airflow in one direction while blocking flow in reverse. define shuttle valve - correct answer ✅is used to automatically select the higher of two pressure sources to supply a pneumatic signal define flow control valves - correct answer ✅used in pneumatic circuits to vary speed of actuators in a specific part of the circuit. define quick exhaust valve - correct answer ✅normally found mounted on the end caps of the cylinders and are used to exhaust air directly to atmosphere at the cylinder rather then the air flowing through the long and restrictive lines back to the control valve.
Level 3 Pneumatics
whats the purpose of a cylinder? - correct answer ✅to convert fluid power energy (compressed gas) into linear mechanical energy that can then perform work. what is a stop tube? - correct answer ✅its a metal collar that fits over the piston rod. its purpose is to keep the piston seperated from the rod gland bushing when a long stroke cylinder is used. actuator cylinder is leaking - correct answer ✅piston seal is leaking a cylinder body seal is leaking - correct answer ✅the packing on the cylinder rod is over tightened,cylinder is misaligned. the cylinder body seal is leaking - correct answer ✅the tie rods holding it together are loose
Level 3 Pneumatics
a cyclone seperator can be used anywhere in the system that moisture might fall out. T or F - correct answer ✅true air recievers are used to store compressed air to take up fluctuations in demand and allow the system pressure to vary within reasonable limits. T or F - correct answer ✅true most compressed air systems run for long distances. this allows the air to cool below its dew point, which causes moisture to fall out of the airstream. T or F - correct answer ✅true flow control valves control the volume and therefore the speed of the actuator. T or F - correct answer ✅true Pilot operation refers to valves that are operated with air pressure. internally piloted means the air pressure within the valve is used to perform the shifting function. T or F - correct answer ✅true
Level 3 Pneumatics
the 3/2 valve can be used if the air needs to be released when the valve is closed. A typical application is the operation of a _________ acting cylinder - correct answer ✅single A __________ acting cylinder is a common application of a 4/2 valve. - correct answer ✅double one of the first items to check in a malfunctioning system is weather there is a supply of air at sufficient flow and pressure. T or F - correct answer ✅true what laws and theories can be applied to both pneumatics and hydraulic systems? - correct answer ✅Pascals law, Bernoullis principles, law of convservation of energy.
