chapter 60-120_part 1 Flashcards
device used for
converting mechanical energy into hydraulic energy
positive displacement hydraulic pump
driven by a
prime mover such as an electric motor
positive displacement hydraulic pump
two functions of the positive displacement hydraulic pump
creates a partial vacuum
mechanical action of the pump
less expensive but limited to
pressures below 140 bar. It is noisy in operation than
either vane or piston pumps
.gear pump
ess expensive but limited to
pressures below 140 bar. It is noisy in operation than
either vane or piston pumps.
gerotor pumps
have both elements
externally driven and neither element has any contact with the
other. For this reason, they are quieter when compared to other
types of gear pumps
lobe pumps
have both elements
externally driven and neither element has any contact with the
other. For this reason, they are quieter when compared to other
types of gear pumps
Screw Pumps
used to regulate and control the
flow and pressure in any assigned manner are called
control valves or simply valves.
Control Valves
three types
of valves employed in hydraulic
systems:
1.Directional control valves
2. Flow control valves
3.Pressure control valves
used to control
the distribution of energy in a fluid power system. They
provide the direction to the fluid and allow the flow in a
particular direction. These valves are used to control
the start, stop and change in direction of the fluid
flow
directional control valves
classification of control valves based on Type of construction:
*Poppet valves
*Spool valves
classification of control valves based on actuating mechanism
*Manual actuation
*Mechanical
actuation
*Solenoid actuation
*Hydraulic actuation
*Pneumatic
actuation
*Indirect actuation
check valve
unidirectional valves
and permit the free flow
in one direction only.
unidirectional valves
and permit the free flow
in one direction only.
spool valve
spool is operated manually. Manual
actuators are hand lever, push button and pedals etc.
Manual actuation
DCV spool can be operated by using mechanical
elements such as roller and cam, roller and plunger and
rack and pinion etc. In these arrangements, the spool end is
of roller or a pinion gear type.
mechanical actuation
also known as an electric actuator
solenoid actuation
usually known as
pilot-actuated valve
Hydraulic actuation
DCV can also be operated by applying
compressed air against a piston at either
end of the valve spool.
Pneumatic actuation
can regulate the flow or pressure of the fluid.
Flow Control Valves
has a plug which can be
adjusted in vertical direction by setting flow adjustment screw.
The adjustment of plug alters the orifice size between plug
and valve seat.
plug or glove valve
consists of a
disc which can rotate inside the pipe. The angle of disc
determines the restriction. Butterfly valve can be made to any
size and is widely used to control the flow of gas.
butterfly valve
This type
of flow control valve uses a ball rotated inside a
machined seat.
ball valve
used to protect the hydraulic components from
excessive pressure. This is one of the most
important components of a hydraulic system and
is essentially required for safe operation of the
system.
Pressure relief valves
