SU61380A1 - Steam boiler power control method - Google Patents

Description

In the practice of operation of steam boilers, especially with a developed screen surface and with a relatively low water content, a sharp increase in the level with increasing load is observed, and with load drops, a decrease in the level. The simplest analysis of this phenomenon is that it is associated with an increase in load, with a drop in pressure in the boiler, and with load drops, with an increase in pressure. The increase and decrease in the water level is caused by an increase or decrease in the steam content of the water volume of the boiler due to the intensification of vaporization when the pressure drops due to the heat accumulated in the water volume, and the decrease in vaporization with increasing pressure.

In conventional types of power controllers, this distinctiveness is not taken into account, especially osh, which is dull for boilers with a relatively low water content. If we consider the operation of the most common two-pulse power regulator (level), in which changes in the water level and change in steam consumption are used as impulses, then we can see that as the load increases,

the regulator, the measured water level and the steam consumption, act in opposite directions: one reduces the water supply due to an increase in level with increasing load, and the other increases the water supply. Practice shows that similar work, with relatively abrupt changes in load, leads to casts or sharp decreases in level.

The proposed method of regulating the power of a steam boiler allows the use of both pulses - changing the water level in the steam pressure in the drum - to act on the supply valve in the same direction.

In the device for the proposed method, the membrane is melada, perceives the vapor pressure, and the spring, balances it, this pressure, separated by a cataract, which transmits the impulse from the vapor pressure during its "3A expansion."

The figure shows a diagram of an apparatus for implementing a method for regulating the power of a steam boiler. When water is supplied to the boiler more than it is consumed, and the vapor pressure remains unchanged, the increase in water level in:

the boiler will force the regulator element, the measuring level (float / in the diagram, and in general it can be any device), rotating around the support A connected with it; the lever, covering the feed valve 2, thereby reducing the supply of water until until the level change stops. Obviously, when there is no change in vapor pressure, the pulse element (membrane 3), which measures the change in pressure, will not move. The regulator in this case works like an ordinary Watt regulator.

With a sharp increase in load, as mentioned above, there will be a sharp increase in the level of AND, on the one hand, and, on the other hand, a sharp drop in pressure in the boiler. A pulse element measuring the level change will cover the water inlet valve; the pulsed organ measuring the vapor pressure will do the same.

When the pressure drops, the stem 4 is membrane 3, the piston 5 cataract b is carried away, filled with oil, there is no sweat upwards the cataract cylinder 6, which is placed between the 3 w membrane by balancing its spring 8. The cataract cylinder connected to the lever 7 will turn the latter around the support B and closes the feed valve 2. Since the spring 8 is under tension, then under its action the cataract cylinder 6, and with it the lever 7, will return to the initial position at which the spring 8 will be unstressed

condition. If, with a sudden change in pressure, the initial position of the ne was restored, then, thanks to the choke 9 which connects the cataract cavities, only the relative position of the Porschenia 5 and the cylinder of the cataract 6, i.e. the pulse part measuring the vapor pressure, changes only during the period of positive or negative values of the derivative of the pressure change over time, and does not react if the derivative is zero.

Also, in case of load shedding, both parts of the controller will work only on opening.

Subject invention

Claims (3)

1. A method for controlling the supply of a steam boiler depending on the water level in the drum and on the pressure in it, wherein both pulses — a change in the water level and a pressure change in the drum — are used to act on the feed valve in the same direction. 2. A method for performing the method according to claim 1, characterized in that the quality of the pulse is based on changes in pressure over time. 3. A device for implementing the method according to claims 1 and 2, characterized in that, in order to transmit a pulse from the vapor pressure, only during the vapor pressure change between the vapor pressure sensing membrane 3 and the balance spring 8 is placed a cataract 6.