IQS Newsroom Articles on Hydraulic Pumps
About Hydraulic Pumps and Hydraulic Pump Manufacturers
Including: Electric
Hydraulic Pump, Hydralic
Pumps, Hydraulic
Gear Pump, Hydraulic
Hand Pump & Hydraulic
Water Pump.
Hydraulic pumps are extremely basic and capable devices
designed to move liquid by pressure or suction. Hydraulic pumps are used to
transfer energy and are powered by an energy source that initializes the pump
but has no part in the pumping action itself. The kinetic energy of the fluid
is used to force a small part of liquid that is under high pressure to a reservoir,
called the pump outlet, which is at a higher level. Commonly, a small diameter
piston is pushed against an uncompressible fluid, such as oil. The smaller
piston causes the oil to move a second, larger piston on the opposite side
of the system, multiplying the force. Hydraulic multiplication factors make
pumps useful in many applications that require great strengths, including automobile
braking systems, dump trucks and construction shovels/excavators.
Hydraulic pump manufacturers produce hydraulic pumps in different varieties,
sizes, flow rates and power ratings. If the cylinder of the hydraulic pumps
is expected to constantly raise a heavy weight, a single piston pump or double-acting
pump is appropriate. In applications that initially have little to no resistance
but require high force later on, a two-speed dual piston pump will suffice.
Hydraulic pumps with a 4-way valve are ideal for applications that call for
a double-acting cylinder, which exerts force in either direction. Hydraulic
pump manufacturers may need to know the weight of the load being lifted by
and the piston diameter of the cylinder, the number of cylinders lifting the
load and the travel length (stroke) of the cylinder, in order to determine
the appropriate type of pump for the application.
Pressure capacities are important factors when purchasing from hydraulic pump
manufacturers. The load is actually what causes the pressure on the fluid,
not the pump itself. The rotary action of the pump simply moves the fluid,
causing flow. Hydraulic pumps pressure rating is determined by the capability
of the pump to withstand pressure without internal leakage or damage to the
pump components. If simple or moderate work is expected, low- and medium-pressure
pumps will do just fine. On the other hand, if a pump will be used for large
construction equipment, a high pressure system will most likely be necessary.
It is difficult to predict when hydraulic pumps will fail. However, new diagnostic
technology has been developed that claims to do just that. The discharge pressure
of hydraulic pumps is directly measured to accurately predict failure and the
remaining life of the pump. This technology improves on the common detection
methods of using vibration signals, which are affected by environmental interference,
by measuring the ripples on the surface of the fluid, which are not affected
by external sources. By easily extracting a "feature signal" from
the pump discharge pressure in real time, it is able to predict failure within
50 to 100 hours, which leads to improved safety and significantly reduced or
eliminated downtime. The system can be economically integrated into new or
existing hydraulic pumps without much modification.
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Types of Hydraulic Pumps
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are energy-saving pumps that are operated by a compressed air source
and require no energy to maintain system pressure. In both the single-
and two-stage air hydraulic pumps, air pressure is simply converted
to hydraulic pressure, and they stall when enough pressure is developed.
-
have pistons that make the strokes in the same direction along the centerline
of the cylinder block.
-
are non-positive displacement pumps that are used in hydraulics requiring
a large volume of flow. Centrifugal pumps operate at fairly low pressures
and are either diffuser or volute types.
- use hydraulic cylinders to provide electric power to machinery.
- are pumps whose output can only be altered by changing
the drive speed.
-
are pumps that operate at extremely high pressures. High pressure pumps
operate in the range of 3,000 to 70,000 psi.
- have intermeshing gears that displace fluid, creating mechanical power.
-
are manually operated to pressurize a hydraulic system. Hydraulic hand
pumps are often used to calibrate instruments.
- convert hydraulic energy to mechanical power.
-
require virtually no maintenance, as they have only two moving parts.
Water from an elevated water source enters one of two chambers through
a relatively long, thick pipe, developing inertia as it moves down to
the second chamber, which starts the pump.
- use hydraulic power to move water from one place to another.
- discharge liquid in a constant flow.
- discharge liquid volumes at separate periods.
-
use pistons that are arranged in a design similar to wheel spokes and
are situated in a small cylindrical block.
-
depend on reciprocating motion in order to transmit fluid from the inlet
side to the outlet side.
-
are a type of positive-displacement pump that use rotational motion
to transfer liquids from the pump inlet to the outlet.
- are pumps in which the clamps and cylinders are
quickly extended by high flow at low pressure in the first stage of
operation. In the second stage, piston pumps build pressure to a preset
level and then maintain that level.
-
are composed of two separate pump assemblies that are contained in a
single housing.
-
have cylinder sizes that are changeable.
Hydraulic Pumps Terms
-
A container that stores fluid under pressure and is utilized as a source
of energy or to absorb hydraulic shock. Accumulator types include piston,
bladder and diaphragm.
- A circumstance
that occurs in pumps when existing space is not filled by available fluid.
Cavitation will deteriorate the hydraulic oil and cause erosion of the
inlet metal.
- A system
in which the pump continually operates against a load, even in the neutral
condition.
- A hydraulic actuator
constructed of a plunger or piston inside a cylindrical housing. The piston
or plunger operates because of pressurized liquid.
- The amount of
liquid transferred from the inlet of the pump to the outlet in a single
revolution. Displacement can be fixed or variable.
- The amount of liquid
volume that passes a given point in a given time. Flow rate is commonly
measured in gallons per minute (gpm).
- Vertical distance measured
between two stages in a liquid.
- The piece
of machinery that receives pressure from the energized fluid and then
converts it to motion and mechanical force.
- A device
that filters out impurities in the liquid used to create mechanical energy.
- A relatively
thick hose that transfers liquids to and from hydraulic pumps.
- Any device used to create kinetic
energy within a hydraulic system. Motors and manual energy are both sources
of power in hydraulic power units.
- A device used to troubleshoot and check hydraulic powered system
components.
- A device used
to regulate water distribution in hydraulic applications.
- The science dealing
with the transmission of force through the medium of a contained fluid.
- A slippery and viscous
liquid that is not miscible with water. Oil is often used in conjunction
with hydraulic systems because it cannot be compressed.
- A system
in which the yield of the pump has a free-flow passageway back to the
reservoir, while in the neutral condition.
- A device used for converting
hydraulic power to mechanical energy. In hydraulic pumps, the piston is
responsible for pushing down and pulling up the ram.
- A mechanical device that
transports liquids and gases by suction or pressure.
- A hydraulic mechanism
that uses the kinetic energy of a flowing liquid to force a small amount
of the liquid to a reservoir contained at a higher level.
- In hydraulics,
the condition engendered by an obstruction or restriction in the flow
path.
- A fastener designed to
provide a perfect and tight closure. Seals prevent environmental materials
from contaminating hydraulic assemblies.
- A device used to regulate
the amount of hydraulic or air flow. In the closed position, there is
zero flow, but when the valve is fully open, flow is unrestricted.
- Pressure in a hydraulic system caused
by kinetic energy.