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General Description and Operating Principle
General Description
Cartridge valves, also known as 2/2–way valves or logic valves,
conform to DIN 24342 and ISO 7368 standards.They have two
operational ports A and B.The flow path between these two
connections is controlled hydraulically by a pilot pressure
applied to X.
Depending on the control input, cartridge valves can
be used as:
➣ Directional Control Valves
(start, stop, directional control)
➣ Pressure Control Valves
(pressure relief, pressure control, pressure sequence
and unloading function)
➣ Check Valves
(check valve function and pilot operated check
valve function)
➣ Flow Control Valves
The preferred mode of mounting is the manifold block,
which can be equipped with several valves depending on the
hydraulic circuit for the specific application. Each valve is
connected to each other in the manifold block.
The Moog Hydrolux product line contains valves of
nominal bores 16, 25, 32, 40, 50, 63, 80 and 100 as per DIN
24342,
for flows up to 10,000 lpm and sizes 125, 160 for flows to
24,000 lpm. Moreover, Moog Hydrolux offers cover plates and
pilot valves for a wide variety of functions.
In addition to this, our product offering also contains
cartridge housings for a great number of applications for
subplate, pipe and flange mounting.
Operating Principle
Cartridge valves have two working connections A and B, where
the main flow is hydraulically operated by a controlling pressure
applied to the connection X.The basic cartridge valve includes
a valve poppet and sleeve which is normally held in the closed
position by a spring.The poppet valve has a seated cone, giving
a leakage free (dependent upon pilot control) condition across
the two ports.The closing spring is retained by the control
cover which encloses the cartridge valve and provides pilot
connections from the X port.Various types of pilot control can
be mounted either to the control cover or to an adjacent
manifold face to provide direct control of the cartridge valve.
The effective areas of the basic element are A
A
,A
B
and A
X
.
Pilot oil can be taken from port A, B or both A and B (with a
shuttle valve) or an external source. Hydraulic fluid can flow
through the 2–way cartridge valve from A➔B or B➔A.
A pilot valve can be used to directly control the switching
function of the cartridge valve, either between two extreme
positions, open or closed, or in any number of intermediate
positions.The exact position of the valve cone depends on the
ratio of control surface A
X
, to the pressures acting from the
working connections A and B on the seating surface of A
A
and
the annular area of A
B
.
If the valve cone is open, by reducing the pressure seen at
X, then flow can move from A and B or vice-versa. By applying a
control pressure at X, the working connections A to B are shut
off as the valve cone is closed by the seat mounting. If there is a
pressure difference between connection B and pilot connection
X, as a result of clearance tolerance between the cone and
sleeve, then leakage can be eliminated by using a leakproof seat
valve and hooking up the pilot connection X to the working
connection B. If the desired function does not permit such a
switching operation, a cartridge valve with an additional sealing
surface can be used to seal the connections A, B and X from
each other.