JPS6113122B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drain recovery device used for returning condensate generated in steam-using equipment to a boiler.

The applicant first installed a drain reservoir in a water supply passage such as between a water supply pump and a boiler, introduced condensate into the drain reservoir when water was not being supplied, and then pressurized make-up water into the drain reservoir during the next water supply. We proposed a drain recovery device that is characterized by pumping hot water to a boiler, etc. If all of the high-temperature condensate to be recovered is introduced into the drain reservoir and replaced with hot water, the low-temperature make-up water that remained at the end of the previous water supply would be extremely efficient, but the amount recovered would be If there was a large amount of water, there was a problem that the introduced hot water would boil and jump out of the drain reservoir.

The present invention aims to solve these problems and provide a drain recovery device with high heat recovery efficiency, in which condensate can be quickly introduced into the drain reservoir, and hot water does not splash out from the drain reservoir. It is.

The drain recovery device according to the present invention has a closed tank that forms a waiting room above the drain reservoir, connects the water supply pump and the lower part of the drain reservoir with a press-fit passage with a check valve interposed, and has a check valve in the upper part of the drain reservoir. mediated by a valve,
A pressure feeding passage connected to a boiler etc. is installed, a condensate inflow passage 14a is connected to a waiting chamber, and a check valve is interposed between the lower part of the waiting chamber and the upper part of the drain reservoir.
b, connect a discharge passage 18a to the lower part of the drain reservoir and raise it above the drain reservoir, interpose an electrically operated valve V1 in the discharge passage 18a, connect the discharge passage to the upper part of the waiting room and lower it. , is connected to the discharge passage 18b above the electrically operated valve V1, an electrically operated valve V2 is interposed in the discharge passage, and a temperature sensor is attached to the lower part of the drain reservoir or outflow passage 18a, and the water supply pump is operated/stopped. When the temperature detected by the temperature detector is higher/lower than a predetermined temperature, the electrically operated valve V1 is closed/opened.
2 is provided with means for controlling the opening/closing of the valve.

The operation of the above drain recovery device will be explained. The water pump will be installed to pump up water from the water tank. The pressure feeding passage is connected to a pressure feeding destination such as a boiler. The condensate inflow passage 14a is connected to a condensate generation location such as steam-using equipment, usually through a steam trap. The outflow passage typically connects to the water supply tank to return excess water.

When the water supply pump is stopped, the electrically operated valve V
1 is operated to the valve open position. In the press-in passage and the pressure-feed passage, the action of the check valves arranged in each prevents backflow from the drain reservoir to the water supply pump and from the boiler to the drain reservoir. Therefore, the condensate flows through the inflow passage 1
It enters the anteroom through 4a and enters the drain reservoir through the inlet passage 14b, and excess water in the drain reservoir is forced out through the outlet passage.

At this time, the temperature of the water in the lower part of the drain reservoir is detected by a temperature sensor, and if the temperature is lower than a predetermined temperature, the electrically operated valve V2 is operated to the closed position, and if it is higher, the electrically operated valve V2 is operated to the open position. Therefore, if the water in the lower part of the drain reservoir is at a low temperature, the condensate will be forced into the drain reservoir under its own pressure.
When the temperature becomes high, the upper part of the anteroom and the lower part of the drain reservoir are communicated through the outflow passage 18a and the discharge passage, so that condensate in the anteroom quietly flows down to the drain reservoir by gravity.

Next, when the water supply pump is operated, the electrically operated valve V1 is simultaneously operated to the closed position and the outflow passage is closed. The water from the water pump pushes open the check valve, passes through the press-in passage, and enters the drain reservoir. Then, the pressure inside the drain reservoir increases and the check valve of the inflow passage 14b is closed, so that condensate cannot flow into the drain reservoir. On the other hand, since the check valve of the pressure feeding passage is pushed open, water in the drain reservoir is forcedly fed to the boiler or the like.

As before, the operation and stop of the water supply pump is controlled according to the water level of the boiler, etc., and the above operation is repeated to automatically collect condensate and supply water.

Here, water naturally accumulates in the drain reservoir at a higher temperature in the upper part and a lower temperature in the lower part, so when water is supplied, the higher the temperature in the upper part, the faster the water is sent to the boiler etc. through the pressure feeding passage. Since the outflow passage is connected to the lower part of the drain reservoir, when the water supply is stopped, the lower temperature water is discharged faster through the outflow passage.

Therefore, according to the present invention, high-temperature condensate is pumped to the boiler with priority over cold water, so the drain recovery efficiency is increased, and the water supply pump only pumps cold water, but not high-temperature hot water. Since it is not necessary to do so, cavitation does not occur.

In addition, when the water temperature in the drain tank is low, the condensate is forced into the drain tank under its own pressure, and when the water temperature becomes high, it flows quietly under the action of gravity, so the heat recovery efficiency is high and the water in the drain tank is It won't fly out.

Next, a detailed explanation will be given based on the illustrated embodiment.

Regarding FIG. 1, make-up water in the water supply tank 1 is pumped up by a pump P and sent under pressure to the boiler 3 through water supply passages 2, 2a, and 2b made of pipe members, etc., but the water supply passage 2 has an appropriate volume. A drain reservoir 4 is provided between the passages 2a and 2b. The drain reservoir 4 can be made by welding disk-shaped plates to openings at both ends of a pipe. The volume of the drain reservoir 4 is determined in consideration of the required amount of water supply, the frequency of water supply, the amount of condensate to be collected, etc. The makeup water inlet 5 opens at the bottom of the drain reservoir 4, and a distribution plate 7 having uniformly distributed pores 6 is attached across the lower part of the drain reservoir 4. A pressure feed port 8 is provided above the drain reservoir 4. The flow in the inflow passage 2 is limited only in the direction of the arrow by the check valves 9 and 10 arranged in the passages 2a and 2b. The steam generated in the boiler 3 is conveyed, for example, to the steam-using equipment 12 via a circular feed pipe 11, where it is condensed and becomes condensate.
4, 14a, and 14b. The inlet passage 14 is provided with a waiting chamber 15 between the passages 14a and 14b, preferably having a sufficient volume to store all the condensate flowing in during the water supply period. The anteroom 15 can be replaced by increasing the diameter of the inflow passage 14, but it can also be made in the same way as the drain reservoir 4 or integrally with the drain reservoir 4. Inflow passage 14b between anteroom 15 and drain reservoir 4
A check valve 16 is disposed at , allowing flow only in the direction of the arrow. When water is supplied, the drain reservoir 4 is pressurized and the check valve 16 is closed. An outflow port 17 opened at the bottom of the drain reservoir 4 communicates with the water supply tank 1 through outflow passages 18, 18a, 18b, and 18c made of pipe members or the like. An electrically operated valve V1 is attached to a passage 18a rising above the drain reservoir 4. The on-off valve V1 is electrically controlled to close when water is supplied and open when water is not supplied. This can be electrically interlocked with a pump P whose operation is controlled by a signal from a liquid level detector 19 of the boiler 3. The pump P is controlled by a signal from the liquid level detector 19 so that, for example, when the water level of the boiler 3 falls to a predetermined low water level BL, the pump P starts operating, and then stops when the water level rises to a predetermined high water level BH. A pressure regulating valve 2 is provided in the horizontal passage 18b.
0 is attached. This valve 20 has a spring and remains closed until the primary side reaches a setting.
Thereafter, a well-known primary pressure regulating valve is used, which opens while maintaining the primary pressure at the set pressure. As a result, the pressure in the drain reservoir 4 will not exceed the set pressure of the pressure regulating valve 20 when water is not supplied. When adjusting the drain reservoir 4 to high atmospheric pressure and the water head pressure of the rising passage 18a, the pressure regulating valve 20 can be omitted. Waiting room 1
A discharge passage 21 is arranged from the upper part of 5, and an electrically operated valve V2 is attached thereto. The discharge passage 21 joins the outflow passage 18 between the on-off valve V1 and the control valve 20. The on-off valve V2 is opened and closed in response to a signal from a temperature sensor 22 disposed at the outlet 17. That is, when water is not supplied, the on-off valve V1 is open, and the drain reservoir 4 can be pressurized to the set pressure of the pressure control valve 20. If the temperature of the hot water in the drain reservoir 4 rises above the saturation temperature corresponding to the set pressure, the inside of the drain reservoir 4 will boil and the internal hot water will flow out through the outflow passage 18. Therefore, by detecting the temperature of the outlet 17 and opening the on-off valve V2 when it reaches an appropriate set temperature lower than the saturation temperature, the above-mentioned blow-off can be eliminated. If the on-off valve V2 is closed until the set temperature is reached and all of the condensate is introduced into the drain reservoir 4, the interior of the drain reservoir 4 can be quickly filled with high-temperature hot water. Normally, when the amount of condensate to be recovered is small and all of it is introduced into the drain reservoir 4 for recovery, the on-off valve V2 and temperature sensor 22 are used to prevent condensate from jumping out in the event that an abnormally large amount of condensate flows in. It is also effective as a safety measure. The set temperature at which the on-off valve V2 should be opened must be determined in consideration of the mixing efficiency of the inflow condensate and the low temperature water in the drain reservoir 4. On the other hand, in order to increase the mixing efficiency, a large number of small holes 23 are provided around the valve. Preferably, a mixing tube 24 is provided.

Next, the operation will be explained with reference to FIG. The figure shows a state in which evaporation has progressed and the water level in the boiler 3 has fallen to the position shown in the figure. At this time, it is assumed that the water supply pump P is stopped, the on-off valve V1 is opened, and the inside of the drain reservoir 4 is still at a low temperature, and the on-off valve V2 is closed. The condensate and partially reevaporated steam are forced into the drain reservoir 4 through the inlet passage 14 . Then, it is mixed with the low temperature water in the drain reservoir 4. The liquid in the drain reservoir 4 is pushed out to the water supply tank 1 through the outflow passage 18 by the amount of condensate that has flowed in. At this time, lower temperature water has a tendency to accumulate at the lower part of the drain reservoir 4, and since the outlet 17 is opened at the lower part of the drain reservoir 4, the lower temperature water is pushed out preferentially, and the drain reservoir 4 The higher the top, the more high-temperature water accumulates. In this way, the condensate is introduced into the drain reservoir 4, and when the outlet 17 reaches the set temperature as close as possible to the point at which the inside of the drain reservoir 4 boils and the internal hot water is blown away, a signal from the temperature detector 22 is activated to open/close the valve V2. is opened, and the re-evaporated steam is discharged from the upper part of the waiting chamber 15, thereby preventing blow-off. The discharge passage 21 merges with the outflow passage 18, and the same pressure acts on the drain reservoir 4 from both the passage 14b and the passage 18a.If the condensate accumulated in the anteroom 15 flows into the drain reservoir 4, the drain reservoir 4 The effect of forcing the lower temperature water out of the passage 18 continues. The pressure regulating valve 20 also acts as a resistance against the discharge passage 21 to reduce the outflow of re-evaporated steam. Next, when the water level in the boiler 3 falls to the predetermined low water level BL, the on-off valve V1 is closed by the signal from the liquid level detector 19, the pump P is driven, and makeup water enters the bottom of the drain reservoir 4 from the pressure inlet 5, and the dispersion plate 7, it spreads to fill the drain reservoir 4, pushes up the hot water in the drain reservoir 4 like a piston, and sends it into the boiler 3 through the pressure feed port 8 through the passage 2b. Since the pressure feed port 8 is located at the upper part of the drain reservoir 4, hot water from the upper part is preferentially sent out. If hot water alone is insufficient, make-up water will continue to be supplied to Boiler 3.
is press-fitted into the During this water supply, the pressure in the drain reservoir 4 is high and the check valve 16 is in a closed state, so that condensate from the steam trap 13 accumulates in the anteroom 15. When low-temperature make-up water is pressurized into the drain reservoir 4, the temperature at the outlet 17 decreases, and the on-off valve V2 is closed in response to a signal from the temperature sensor 22 that detects this. Steam trap 1 is closed because the water supply time is long and the discharge passage 21 is closed.
If there is a risk of an obstruction in the condensate discharge to the pump 3 or steam-using equipment 12, etc., the electrically operated valve V2 may be controlled to open when water is not being supplied. When the water level in the boiler 3 reaches a predetermined high level BH, the water supply pump P is stopped by a signal from the liquid level detector 19, and the on-off valve V1 is opened. At this time, the on-off valve V2 is closed.
Then, the condensate accumulated in the waiting chamber 15 blows out from the pores 23 of the mixing pipe 24 and mixes with the low-temperature water in the drain reservoir 4, and the excess low-temperature water is discharged from the outflow passage 18 to the water supply tank 1. In this way, all of the condensate is introduced into the drain reservoir 4 through the inflow passage 14, and the inside of the drain reservoir 4 is quickly replaced with hot water. is the drain sump 4
It will be introduced in As the evaporation progresses, the state shown in the figure is reached, and the operations described above are repeated.

As can be easily inferred from the above explanation,
By predicting the time from the end of the previous water supply until the inside of the drain reservoir 4 boils, without using the temperature detector 22,
It is possible to use a timer means that controls the on-off valve V2 to be closed for a predetermined set time from the end of the previous water supply and opened at other times. FIG. 2 is an example of a time cheat that uses such a timer means to control the electrically operated valve V2. Pump P is started at time T1, and at this time valve V1 is closed and valve V2 is open. Then, at time T2, when the water supply ends and the pump P stops, the valve V1 opens and the valve V2 closes. Valve V2
The valve continues to be closed until time T3, which is before the time when the inside of the drain reservoir 4 is estimated to boil, and then, until time T1', the pump P and valve V1 repeat the same operation as last time.

As can be easily inferred from the above explanation, even if valve V1 is closed at the same time when valve V2 is opened at time T3, the benefits of the present invention are not impaired. In other words, if it is thought that the inside of the drain reservoir 4 will boil if more condensate is allowed to flow into the drain reservoir 4, if the valve V1 is closed to prohibit the flow of water through the outflow passage, the heat inside the drain reservoir 4 will be reduced. Water cannot jump out.

As described above, according to the present invention, the low-temperature make-up water in the drain reservoir is quickly replaced with high-temperature hot water after the previous water supply ends, and the internal hot water does not spill out due to the inside of the drain reservoir boiling. A drain recovery device with high recovery efficiency can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a drain recovery device according to one embodiment of the present invention, and FIG. 2 is a time cheat explaining the operation of another embodiment. P is a water supply pump, V1 and V2 are electrically operated valves, 2
1 is a water supply passage, 3 is a boiler, 4 is a drain reservoir, 14 is an inflow passage, 15 is a waiting room, 17 is an outlet, 18 is an outflow passage, 20 is a pressure control valve, 21 is a discharge passage, 2
2 is a temperature detector.

Claims (1)

[Claims] 1 A boiler in which a drain reservoir and an anteroom are formed above the drain reservoir in a closed tank, a water supply pump and the lower part of the drain reservoir are connected by a press-in passage with a check valve interposed, and a check valve is interposed in the upper part of the drain reservoir. The condensate inlet passage 14a is connected to the anteroom, and the lower part of the anteroom and the upper part of the drain reservoir are connected by the inlet passage 14b with a check valve interposed between them. A discharge passage 18a is connected to the upper part of the waiting room and raised above the drain reservoir, an electrically operated valve V1 is interposed in the discharge passage 18a, and a discharge passage 18a is connected to the upper part of the waiting room and lowered, and above the electrically operated valve V1. Connected to the discharge passage 18b, an electrically operated valve V2 is interposed in the discharge passage, and the drain reservoir or outflow passage 18 is connected to the discharge passage 18b.
A temperature sensor is installed at the bottom of a, and the electrically operated valve V1 is closed/opened when the water supply pump is running/stopped, and when the temperature detected by the temperature sensor is higher/lower than a predetermined temperature, the electrically operated valve V1 is closed/opened. A drain recovery device equipped with means for controlling V2 to open/close the valve.