JPS6113525B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drain recovery device for pressure-feeding condensate generated in steam-using equipment to a boiler or the like.

Conventionally, hot water was mixed with cold water in a water supply tank to lower the temperature, and then the water was pumped to the boiler using a water supply pump. However, due to the cavitation of the pump, only relatively low-temperature water could be sent. Ta. In addition, a circulation passage connecting the discharge port and suction port of the water supply pump was installed, and an ejector was interposed therebetween to suck in condensate and increase the pressure at the suction port to prevent cavitation of the pump. The problem was that pump efficiency was significantly reduced.

An object of the present invention is to provide a simple and convenient drain recovery device that can pump condensate to a boiler or the like with high pump efficiency without causing cavitation in the feed water pump.

The drain recovery device according to the present invention includes a drain reservoir formed in a closed tank, a water supply pump and a lower part of the drain reservoir connected by a press-fit passage with a check valve interposed therebetween, and a check valve interposed in the upper part of the drain reservoir. , install a pressure feed passage connected to a boiler, etc., connect the condensate inflow passage with a check valve to the upper part of the drain basin, connect the drainage passage with a drain valve to the lower part of the drain basin, and A means for operating the drain valve is provided so that the drain valve is closed during operation and opened when stopped, and an automatic exhaust valve is placed above the drain reservoir, or an automatic exhaust valve is installed when the water supply pump is stopped and the liquid in the drain reservoir is opened when the water supply pump is stopped. It is equipped with an exhaust valve that is closed when the liquid level reaches a predetermined level using a means for detecting the liquid level.

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 inlet passage is connected to a condensate generating location such as a steam-using device, usually via a steam trap. The drain passage is usually connected to return excess water to the water tank.

When the water supply pump is stopped, the drain valve is operated to the 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. Thus, condensate enters the drain sump through the inlet passage and excess water in the drain sump is forced out through the drain passage.

Next, when the water supply pump is operated, the drain valve is simultaneously operated to the closed position and the drain 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, as the liquid level in the drain reservoir rises, the upper gas is discharged from the automatic exhaust valve or the exhaust valve. When the gas is completely discharged, the automatic exhaust valve closes, or when the water level reaches a predetermined high level as determined by the liquid level detection means, the exhaust valve closes.
Then, the pressure in the drain reservoir increases and the check valve of the inflow passage is closed, so that condensate cannot flow into the drain reservoir. Since the check valve in the pressure feed passage is pushed open, the water in the drain reservoir is forced to be 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. The discharge passage opens at the lower part of the drain reservoir, and when the water supply is stopped, the lower temperature water is discharged faster through the discharge 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 and does not pump high-temperature hot water. Cavitation does not occur because it can be carried out evenly.

Furthermore, the gas in the drain reservoir is reliably removed by an automatic exhaust valve or an exhaust valve, and only condensate or make-up water can be pumped to a boiler or the like.

The illustrated embodiment will now be described in detail. When the water level of the boiler 1 is between the high water level BH and the low water level BL, the water supply pump 5 arranged in the press-in passage 4 that communicates the bottom of the water tank 2 and the drain reservoir 3 is stopped by a signal from the liquid level detector 6. A check valve 7 prevents backflow from the drain reservoir 3 to the water supply tank 2. The exhaust valve 9 of the exhaust passage 8 that communicates the upper part of the drain reservoir 3 with the water supply tank 2 is opened by electrical operation, and the inside of the drain reservoir 3 is regulated while discharging the upper gas by the primary pressure regulating valve 10. The pressure is maintained by the valve 10. The pressure inside the drain reservoir 3 is relatively low, and the check valve 12 prevents backflow from the boiler 1 to the drain reservoir 3 through the pressure passage 11. The discharged condensate passes through the inflow passage 14 and the check valve 1
5 into the drain reservoir 3. Drain reservoir 3
An electrically operated drain valve 17 and a detector 18 for detecting the temperature of the passage 16 are disposed in a drainage passage 16 that communicates the bottom of the water supply tank 2 with the water supply tank 2 . If the temperature of the drain passage 16 is lower than the set temperature when the liquid level in the drain reservoir 3 is between the high water level TH and the low water level TL, the drain valve 17 is activated by a signal from the temperature sensor 18 that detects this. When the drain valve 17 is opened and the liquid level in the drain reservoir drops to the low water level TL, the drain valve 17 is closed by a signal from the liquid level detector 19. In this way, the low temperature water in the drain reservoir 3 is automatically drained. When the liquid level in the drain reservoir 3 reaches the high water level TH due to the inflow of condensate, the drain valve 17 opens in response to a signal from the liquid level detector 19 that detects this, and the condensate in the drain reservoir 3 is discharged. ,
When the liquid level drops to TL, the drain valve 17 is closed by a signal from the liquid level detector 19. Since the volume of the drain reservoir 3 is designed taking into account the amount of water supplied to the boiler 1 at one time, the above-mentioned drainage is actually performed when the amount of condensate generated increases rapidly. When the liquid level in the boiler 1 drops to BL, the drain valve 17 is activated by the signal from the liquid level detector 6.
is closed, the water supply pump 5 is driven, and the make-up water in the water supply tank 2 is forced into the drain reservoir 3.
A check valve 15 prevents backflow in the inlet passage 14, and the high pressure of the boiler 1 is acting on the pressure feed passage 11, so the check valve 12 does not open, and as a result, as the liquid level in the drain reservoir 3 rises, the upper part The remaining gas is exhausted through the exhaust passage 8, and when the liquid level rises to the high water level TH, the exhaust valve 9 is closed by the signal from the liquid level detector 19, the pressure inside the drain reservoir 3 becomes even higher, and the high temperature water is Backed by makeup water, the check valve 12 of the pressure feeding passage 11 is pushed open and the water is fed into the boiler 1. When the liquid level in the boiler 1 reaches the high water level BH, the drive of the water supply pump 5 is stopped by a signal from the liquid level detection means 6, and since the liquid level in the drain reservoir 3 is at the high water level TH, the drain valve 17 is opened to drain water to the low water level TL, and at the same time, the exhaust valve 9 is opened to introduce condensate from the inlet passage 14 into the drain reservoir 3. At this time, a large number of small holes are bored in the peripheral wall of the liquid immersion part of the introduction pipe 20, so that re-evaporation of the condensate water is suppressed and it mixes with the residual cold water. Then, the liquid level in the drain reservoir 3 rises, while the liquid level in the boiler 1 falls due to evaporation, resulting in the state shown in the figure. From then on, the above-mentioned operations are repeated to recover the drain. Here, the set water levels TH and TL of the drain reservoir 3 or the set temperature of the temperature sensor 18 of the drain passage can be freely adjusted according to the situation of drain recovery, and efficient recovery can be performed. Further, the water supply pump 5 does not forcefully feed hot water, and cavitation does not occur. Since the hot water in the drain reservoir 3 is sent under pressure to the boiler 1 before the make-up water in the water supply tank 2, the drain recovery efficiency is high. As is clear from the above, gas is not forced into the boiler 1, and condensate can be easily introduced into the drain reservoir 3.

[Brief explanation of the drawing]

The drawing is a schematic diagram of a drain recovery device according to an embodiment of the present invention. 1 is the boiler, 2 is the water tank, 3 is the drain reservoir,
5 is a water supply pump, 9 is an exhaust valve, 10 is a pressure control valve, 13 is a steam trap, 17 is a drain valve, 1
8 is a temperature detector, and 19 is a liquid level detector.

Claims (1)

[Claims] 1. Form a drain reservoir in a sealed tank, connect the water supply pump and the lower part of the drain reservoir with a press-in passage with a check valve interposed, and connect the water supply pump with a check valve in the upper part of the drain reservoir to a pressure destination such as a boiler. Install a connecting pressure passage, connect the condensate inflow passage with a check valve to the upper part of the drain sump, and connect the drainage passage with a drain valve to the lower part of the drain sump. A means is provided to operate the drain valve so as to close the valve and open it when the water pump is stopped, and an automatic exhaust valve is installed above the drain reservoir, and a means that opens when the water supply pump is stopped and detects the liquid level in the drain reservoir during operation. A drain recovery device equipped with an exhaust valve such as an electrically operated exhaust valve that closes when the liquid level reaches a predetermined high level.