ET 340 Test 1 Questions with Correct Answers

ET 340 Test 1 Questions with Correct Answers Fluid Delivery - Answer-Associated with the fluid output of a pump, determined by the size of the unit pumping chamber. Fixed-delivery pumps - Answer-Constant fluid output for each pump revolution. Variable-delivery pumps - Answer-Produce fluid output from zero, or no flow per revolution, to the maximum allowed by the size of the unit. Pump Design/Selection Factors - Answer-• Operating pressure • Flow requirements • Circuit cycle rate • Expected length of service • Environmental conditions • Cost Gear Pumps - Answer-Positive-displacement, rotary units Gear Pumps - Answer-One gear of the pumping mechanism is turned by the prime mover, the second gear serves as the driven gear. The unmeshing and meshing of the gear teeth as the gears rotate, results in the pumping mechanism. External-gear pumps - Answer-These have teeth on the outside of the rotating shafts. External-gear pumps - Answer-• Most popular in the hydraulic field. • Compared to other designs of similar displacement and operating characteristics, these are generally low cost. • Provide good life-expectancy, and stand up well when subjected to typical fluid contamination. • Available in pressures up to 3000 psi, and flow capacities up to 150 gpm. Internal-gear pumps - Answer-In this design one of the gears has external teeth and the other has internal teeth. Most common Internal-gear pump design. - Answer-Gerotor __________________ design is similar to the Gerotor, but the pumping chamber also has a fixed, ______________-shaped element. - Answer-Crescent Power Unit - Answer-Provides the energy for operation of the system, move the fluid through the system, and provide a safe maximum limit on system pressure while assisting in maintaining proper system operation temperature and fluid cleanliness. Coupler - Answer-In most HPS, the prime mover is mechanically ________________ directly to the input shaft of the system pump. Coupler - Answer-Used to maintain proper alignment between the input shaft and the system pump. Coupler - Answer-The _______________ ratings should match the rated speed, load, and allowable misalignment factors. Belt, chain, and gear coupler - Answer-These types of connections are less efficient, and have a lower safety factor, and place higher stress on the equipment. But, they may be required in situations where changing to a higher or lower speed is required. Positive-displacement pumps - Answer-Produce a constant output for each revolution of operation over a wide range of operating pressures. Positive-displacement pumps - Answer-They have very close tolerances between moving and stationary parts. Positive - Answer-Most hydraulic system pumps are _____________ - displacement. Non-positive-displacement pumps - Answer-These have larger clearances between moving and stationary parts. Because of this, design factor, considerable slippage can occur in the pumping chamber, resulting in pump flow variations as system operating pressures change. Non-positive - Answer-______________________ - displacement pumps are usually used in low-pressure applications, such as fluid transfer, rather than for actuator operation. Rotary - Answer-Use rotating pumps in the pumping chamber to produce the increase and decrease in volume needed to move fluid. Rotary - Answer-______________ motion may also be used to drive the component parts that develop centrifugal force. Reciprocating - Answer-Use the up-and-down linear movement of piston in a cylinder or similar structure to move the fluid. Reciprocating - Answer-As the piston moves downward, the volume of the chamber above the piston enlarges, which creates the low-pressure area needed to bring fluid into the pump from the reservoir. Reciprocating - Answer-The upward movement of the piston reduces the volume of the chamber, which pressurizes the fluid and moves it out of the pump under pressure. Each of the simple machine types... - Answer-Serve a specific purpose that cannot be duplicated by any of the others