The boiler main control technology lies in the coal efficiency and uses electricity the efficiency, the traditional method use air throttle thrustplate and the valve control air blower, makes up the water pump, the circulating pump current capacity, it designs considered by no means energy conservation goal, simultaneously, production craft and production task different, when steam demand quantitative change, must change to the coal (spurts falls) the quantity, achieved high efficiency burning, the traditional control mode uses the manual control, consumes the electricity to be high, the control precision generation, also must the extremely skilled technical personnel operate, the chimney only then can emit the black smoke. The boiler because is often insufficient, when must again open a parallel use, lunch steam pressure demand quantity insufficient two, Chang Xupai the 空放 steam, reduces the steam pressure, both waste energy and pollution environment.

Second, boiler water supply control system transformation
In the traditional boiler water monitor system, the feed pump is the continual constant speed movement, and the current capacity control is realizes through the adjustment 水管�?center regulating valve and the backflow leg. These two methods all have the obvious flaw. Uses when the regulating valve adjusts, because the valve opens reducing, the water pump exports the pressure will be able to rise the valve two side differential pressure to increase. When increases to is very big not only can create the water pump the energy waste, moreover causes this water pump the vibration and the attrition enlarges, then loss of life. Uses when the backflow leg adjusts, the massive water backflow also similarly creates the energy the consumption.
Water pump principle of work
May know the current capacity and rotational speed N by the water pump principle of work has the direct ratio, lifts H and the rotational speed N square has the direct ratio, shaft power P and rotational speed N cubic has the direct ratio, the electrical machinery rotational speed and supply frequency F has the direct ratio, therefore the change supply frequency, may change the electric motor is the feed pump rotational speed, thus achieves the adjustment to the water current capacity goal.
System composition and principle
This system mainly is composed by a monolithic integrated circuit and a frequency changer, here steam drum water level is controlled the variable, for the water volume and the transpiration rate is two auxiliary impulses, these three variables are change delivering by the electrically operated difference pressure to carry on the examination, then passes through the single electrical machinery computation to output 4 ~ 20mA the electric current signal control frequency changer to realize the feed pump rotational speed adjustment.
When design system, first should determine the frequency changer the output frequency, because this parameter choice relates the overall system the control effect, should act according to the water pump current capacity, lifts and so on the parameter and most greatly and slightly determined with the water volume with the water volume.
Frequency changer active status
Frequency changer through and exterior electric circuit connected input output terminal establishment. Manual and automatic two kind of active status, the manual active status through adjusts the potentiometer to assign the frequency changer output frequency, this kind of active status is when some kind of situation stops using carries on the operation in the single electrical machinery, when automatic mode carries on the control by the monolithic integrated circuit output signal.
In the practical application, this system compares the merit which the traditional regulating valve control mode is most solid is the same time electricity saving rate reaches as high as nearly 20% and the water pump to wear serious issue to be solved, the service rate obviously reduces, lengthens the equipment the service life moreover to be able to enhance the system well the automated level.
Third, the boiler drum (directs) the wind control system transformation
The boiler drum (directs) the air blower amount of wind also is frequently changes, because the steam quantitative change is frequently changes, therefore the amount of wind needs frequently to adjust like by the valve regulation, boiler control room to valve distance farther, operation extremely inconvenient, also is impossible to adjust appropriately, amount of wind adjustment oversized, the air oxygen content exceeded the allowed figure, wastes the heat energy, the amount of wind has adjusted excessively slightly, 煤渣 the residual carbon share exceeded the allowed figure has wasted the coal, therefore in order to raise the control level, guaranteed the air oxygen content and 煤渣 the residual carbon share reached the sign, had to carry on the effective adjustment to the amount of wind, the adjustment way, Must convenient, keen, be reliable.
In order to enhance the boiler amount of wind the control level, also can achieve the energy conservation the effect, selects the frequency conversion velocity modulation method to carry on the adjustment to the amount of wind, is the first choice plan. Because the application frequency conversion velocity modulation technology may act according to uses the steam quantity the change, adjusts the drum drawing fan as necessary the rotational speed, reduced the noise (electrical machinery to move to the environment pollution below rated speed, wind noise along with it drop) to raised the industrial hygiene level to play the certain role, because the drum drawing fan was lower than the rated speed under the condition to move for a long time the electrical machinery and the air blower bearing is not easy to damage, lengthened the service life, the electrical machinery calorific capacity also reduced, the service quantity dropped. The down time reduced, saved the massive maintenance cost.
Using frequency changer energy conservation effect
The general use air blower, the water pump equipment fixed amount of wind, the current capacity, usually all surpass the actual need the amount of wind current capacity, and further because needs to change the amount of wind, the current capacity for the technological requirement in the movement, but at present, uses the thrustplate or the valve adjusts the amount of wind and the current capacity adjustment way more universal, although the method is simple, but is in fact through the artificial increase resistance means achieved the adjustment the goal, this kind of throttle adjusts the method waste massive electrical energies, recycles this part of electrical energy to lose can receive the very big energy conservation effect.
Follows the current the body mechanics principle to know that, the air blower amount of wind and the rotational speed and the electrical machinery power relations, indicated with the following relational type:
The in the formula, the Q - amount of wind (current capacity) the H - wind pressure (lifts) P - the shaft power n - rotational speed
When amount of wind reduction air blower rpm drop, its electric motor power input rapidly reduces, for example the amount of wind drops to 80%, the rotational speed (n) also drops to 80% time its shaft power drops to the rated power 51%; If the amount of wind drops to 50%, the shaft power will drop to the rated power 13%, its electricity saving potential was extremely big, gets down attempts between two curves the shadows partially to express selected the frequency conversion velocity modulation method the electricity saving effect.
The above principle also basically is suitable for the water pump, therefore to the amount of wind flow control scope bigger air blower water pump, uses the velocity modulation to control replaces the air throttle or the valve regulation, realizes the energy conservation effective way.
Actuates the air blower, the water pump, the majority for the exchange asynchronous machine, (high efficiency most for synchronous machine), the asynchronous motor or the synchronous motor rotational speed and power source frequency f has the direct ratio, changed the stator power supply frequency to change the electric motor rotational speed, the frequency conversion speeder, was the electrical network 50Hz alternating current, turns the alternating current which the frequency variable voltage might move to actuate the motor realization velocity modulation.
The frequency conversion velocity modulation characteristic is the efficiency high, because has not modulated velocity the attachment 转差 loss which brings, the velocity modulation scope in a big way, the precision is high, the stepless speed regulation. Easy to realize the coordination control and the closed-loop control, because may use the original mouse cage type electric motor, therefore specially suits to the old equipment technological transformations, it both maintained the original electric motor structure simple, reliable has been durable, the maintenance convenient merit, and could achieve the electricity saving the remarkable effect, was a more ideal method which the air blower water pump conserved energy.

Uses the water chestnut branch frequency changer velocity modulation, may substitute for the air throttle thrustplate valve control current capacity, and control stoker, for coal amount transformation effect as follows:

1st, economical uses electricity approximately 30%-80%, approximately 6-9 month is the return on investment.

2nd, the enhancement combustion efficiency, the festival economizes about coal 10%.

3rd, reduces discharges fume the density, avoids braving the black smoke the environmental pollution.

4th, does not need to rely on the experienced operator, may the data control.

5th, may the split-ring or the closed-loop control, also may select the RS-485 communication connection to make the computer common control.

6th, when many boilers parallel operation controls conveniently.

7th, actuates the electrical machinery 软起�? does not have the starting the impact class.