Pulp and Paper Multiple Choice Questions on “Hydraulic Power Systems”.
1. The confined liquid merely transmits the force generated by the power supply; the flow contributes to the other component of work, which is the displacement.
a) True
b) False
Answer: a
Clarification: When force is applied to the piston the pressure exerted on the H2O is transmitted equally throughout the H2O so that H2O comes out of all the holes with equal force. When pressure is applied at a point in a confined fluid, it is transmitted equally in all directions.
2. The liquid must flow to cause motion, its velocity is usually sufficiently high so as to have only a ___________ kinetic energy component relative to the overall work accomplished.
a) Big
b) Small
c) Zero
d) Not valid
Answer: b
Clarification: The power supply might be an electric motor, gasoline engine, or hand power. Although the liquid must flow to cause motion, its velocity is usually sufficiently low so as to have only a small kinetic energy component relative to the overall work accomplished making the hydrodynamic component a trivial consideration.
3. Some common systems that utilise hydraulics are hand operated hydraulic jacks and presses, power steering and brakes on many vehicles, backhoes, and hitch controls of agricultural tractors.
a) True
b) False
Answer: a
Clarification: The hydraulic press depends on Pascal’s principle: the pressure throughout a closed system is const. One part of the system is a piston acting as a pump, with a simple mechanical force acting on a small cross-sectional area; the other part is a piston with a larger area which generates a large mechanical force. Only small-diameter tubing which more easily resists pressure is required if the pump is separated from the press cylinder.
4. When fluid is in static equilibrium it obeys ___________ That is, it is only under compressive forces and those forces act with equal intensity in all directions at any point in the fluid.
a) Poisson’s law
b) Pascal’s law
c) Kraft’s law
d) Lignin law
Answer: b
Clarification: Pascal’s law or the principle of transmission of fluid-pressure It’s a principle in fluid mechanics that states that a pressure change occurring anywhere in a cramped incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere. The pressure is normal (90°) to any surface on which it acts.
5. It takes many operations of the hand pump to lift the object a suitable distance. A ___________ valve allows flow in one direction only so that several operations of the handle might be combined to lift the load.
a) Gate
b) Needle
c) Check
d) Throttle
Answer: c
Clarification: Check valves are 2 port valves, meaning they have 2 openings in the body, one for fluid to enter and the other for fluid to leave. There are many types of check valves utilised in a wide variety of applications. It works by means of a ball that seats against a seal.
6. ___________ is valid for any fluid (liquid or gas); it is especially crucial to fluids moving at a high velocity. Its principle is the basis of venturi scrubbers, thermo—compressors, aspirators, and other devices where fluids are moving at high velocities.
a) Poisson’s principle
b) Pascal’s principle
c) Kraft’s principle
d) Bernoulli’s principle
Answer: d
Clarification: An enlargement in the velocity of a fluid along with a decrement of pressure. Swiss scientist, Daniel Bernoulli, demonstrated that, in most cases, the pressure in a liquid or gas lessen as the liquid or gas moves faster.
7. The ___________ is a measure of how the viscosity changes with temperature; the higher the index, the smaller is the change in viscosity with temperature.
a) Viscosity index
b) Gravity index
c) Pulping index
d) Starch index
Answer: a
Clarification: It’s an arbitrary measure for the change of viscosity with variations in temperature. The lower the index, the greater the change of viscosity of the oil with temperature and vice versa. It is utilised to characterize viscosity changes with relation to temperature in lubricating oil.
8. ___________ are utilised to maintain a reserve of fluid; they have secondary purposes of oil cooling and separation of air and contaminants from the oil.
a) Pond
b) Reservoir
c) Pit
d) Spot
Answer: b
Clarification: A reservoir is an artificial lake where H2O is stored. Most reservoirs are formed by constructing dams across rivers. A reservoir could also be formed from a natural lake whose outlet has been dammed to control the H2O level.
9. Reservoirs should be relatively high and narrow to give a column of fluid ___________ the pump inlet. This lessen the chance of air entering the system by formation of a vortex.
a) Below
b) Above
c) At level
d) Far away
Answer: b
Clarification: Sometimes in such reservoirs the new top H2O level exceeds the H2O shed height on one or more of the feeder streams. In such cases additional side dams are required to contain the reservoir.
10. Hydraulic fluid might be transferred with pipes, tubing, or hose. Pipes are often of (non-stainless) ___________ material.
a) Copper
b) Zing
c) Aluminium
d) Steel
Answer: d
Clarification: These don’t utilise galvanized steel since zinc is fairly reactive with some fluid additives. They are rigid and not meant to be bent. The schedule no. refers to the wall thickness; the actual thickness and pressure rating depend on the overall nominal pipe diameter.
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