working principle
Concrete mixing station is divided into
four parts: gravel feed, powder (cement, fly ash, expansion agent, etc.) to
feed, water and admixture feeding, transmission and storage and storage.The
working process shown in Figure 1 , The mixer control system power, enter the
man-machine dialogue interface, the system initialization processing, including
the recipe number, concrete grade, slump, the production side, etc. According
to the weighing of the silo, metering bucket Detection, the output material
empty or material full signal, prompts the operator to determine whether to
start the mixing control program. Start sand, stone belt motor feed to the
metering bucket; open fly ash, cement tank butterfly valve, start screw motor
transmission fly ash , The cement to the metering bucket; open the silo and
admixture pool control valve so that water and admixtures flow into the
metering bucket. Metering to meet the set requirements to open the metering
Doumen, ingredients into the mixer has been started stirring mixing, to set
Time to open the mixer door, concrete has been mixed into the mixer.
1. Each cylinder, control valve and motor
are operated according to the requirements of the concrete mixing process. The
control of each cylinder, control valve and motor must be accurate, stable and
reliable.
2 control system with automatic, manual two
modes of operation, and the relationship between each other is independent of
each other constraints.
3 system has a good anti-interference
ability and improve the alarm self-protection function.
4 through communication with the computer,
you can display system operating status, fault alarm.
Gas
supply failure
(1) air
compressor failure are: check valve damage, piston ring wear serious damage to
the intake valve and air filter plug.
To
determine whether the check valve is damaged, just shut down the air compressor
automatically after ten seconds, turn off the power to move a large tape wheel
by hand, if you can more easily turn a week, then the check valve is not
damaged ; In
addition, the check valve has been damaged; In addition, the automatic pressure
switch can also be exhaust from the exhaust below the situation to judge,
usually in the air compressor automatically shut down after about ten seconds
after the stop exhaust, If the exhaust has been
in the air compressor until the start again to stop, then the check valve is
damaged, to be replaced.
When
the air compressor pressure rise is accompanied by a string of oil phenomenon,
indicating that the air compressor piston ring has been seriously worn, should
be replaced.
When the inlet
valve sheet is damaged or the air filter is blocked, the air compressor
pressure will rise slowly (but there is no string of oil phenomenon). If
the suction is small, generally the air filter is dirty, the air filter is
dirty. If the suction pressure is low, the air filter is dirty. If the air
filter is dirty, The filter should be
cleaned or replaced.
(2) pressure reducing
valve failure: pressure is not high, or pressure rise slowly.
Pressure
adjustment is not high, often due to pressure regulating spring fracture or
diaphragm caused by rupture, must be renewed; pressure rises slowly, usually
due to the filter is blocked, should be removed and cleaned.
(3) pipeline
failure: pipeline joints leak, hose rupture, condensate accumulation.
Pipe
joints leak and hose rupture from the sound up to determine the location of
leakage, should be promptly repaired or replaced; if the pipeline in the
accumulation of condensed water, should be promptly drained, characterized by
condensation in the north of the winter easy to knot Ice and plug the gas path.
(4)
Compressed air handling components (triple) of the fault are: oil-water
separator failure, pressure regulator and oil mist device failure.
Oil-water separator
failure is divided into the filter plug, damaged, moving parts of the sewage
valve moving parts are not flexible and so on. Work should always clean the filter,
remove the dirt inside the dirt and impurities.
The fault of the
pressure regulating valve is the same as the above "(2) Failure of the
pressure reducing valve".
Oil mist device
failure phenomena are: not drop oil, oil cup at the bottom of the deposition of
water, oil cup mouth seal damage. When
the oil mist is not dripping, check whether the airflow of the air inlet is
lower than the fog flow, whether the air leakage, oil adjustment needle is
blocked, etc .; if the oil cup bottom water, should be excluded; When the sealing ring is damaged, it should be
replaced in time.
Cylinder failure
Due
to improper assembly and long-term use of the cylinder, the pneumatic actuator
(cylinder) prone to internal and external leakage, the output power is not
enough and the action is not smooth, poor cushioning, piston rod and cylinder
head damage and other symptoms.
(1)
the cylinder appears inside and outside the leak, usually due to eccentric
piston rod installation, lack of oil supply, seals and seal rings wear or
damage, the cylinder impurity and the piston rod caused by scars and so on. Therefore,
when the cylinder inside and outside leakage, should re-adjust the center of
the piston rod to ensure that the piston rod and cylinder coaxial; must always
check the reliability of the work of the oil mist to ensure that the
implementation of good lubrication components; Ring and
seal ring wear or damage ring, must be promptly replaced; if there is
impurities in the cylinder, should be promptly removed; piston rod when there
is scar, should be renewed.
(2) the
cylinder output force and the action is not smooth, usually due to the piston
or piston rod is stuck, poor lubrication, air supply is insufficient, or the
cylinder with condensed water and impurities and other reasons. In this regard, the center of the
piston rod should be adjusted; check the operation of the oil mist is reliable;
air supply pipe is blocked. When
the cylinder has condensed water and impurities, should be promptly removed.
(3) cylinder cushioning
effect is poor, usually due to buffer ring wear or damage caused by adjustment
screw. In this case, replace the
seal ring and adjustment screw.
(4) cylinder
piston rod and cylinder head damage, usually due to eccentric piston rod or
buffer mechanism does not work caused. In this regard, adjust the
center of the piston rod position; replace the buffer seal or adjustment screw.
Reversing valve failure
Valve
failure: valve can not be reversed or slow commutation, gas leakage, solenoid
pilot valve failure.
(1)
reversing valve can not be reversed or slow action is generally due to poor
lubrication, the spring is stuck or damaged, oil or impurities stuck in the
sliding part of the cause. In
this regard, you should first check the work of the oil mist device is normal;
the viscosity of lubricating oil is appropriate. If necessary, replace the
oil, clean the sliding part of the valve, or replace the spring and the valve.
(2) valve
after a long period of time easy to use spool seal wear, valve stem and valve
seat damage phenomenon, resulting in valve gas leakage, the valve action is
slow or not normal change and other failures. At this point, should replace the
seals, stem and seat, or replace the valve.
(3)
If the electromagnetic pilot valve into the exhaust vents are sludge and other
debris blocked, closed lax, stuck active core, the circuit is faulty, can cause
the valve can not be normal change. The first three kinds of conditions should be
cleaned of the pilot valve and the activities of the core of the sludge and
impurities. The circuit fault
is generally divided into two types of control circuit failure and
electromagnetic coil failure. Check the
circuit fault, the valve should be manually turned a few knobs to see the rated
pressure in the valve under normal commutation, if the normal commutation, the
circuit is faulty. Check,
the instrument can be used to measure the voltage of the solenoid coil to see
whether the rated voltage, if the voltage is too low, should further examine
the control circuit and the associated power switch circuit. If the change in the rated
voltage valve can not be normal, you should check the solenoid coil connector
(plug) is loose or contact is not real. Method
is to unplug the plug, measuring the resistance of the coil (generally should
be a few hundred ohms to several thousand ohms), if the resistance is too large
or too small, indicating the solenoid coil is damaged, should be replaced.
Component failure
Pneumatic
components failure are: oil mist device failure, automatic sewage device
failure, muffler failure.
(1) the failure
of the oil mist device: regulating the amount of needle adjustment is too small
oil blockage, pipeline leakage and so will not liquid droplets atomization. In this regard, should be promptly
dealt with congestion and leakage of the place, adjust the amount of drip oil
to reach about 5 drops / min. Normal
use, the oil cup to keep the oil in the upper and lower limits within. The bottom of the oil cup of water, should be
promptly ruled out.
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