JPS5856043B2 - Drain collection device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a boiler drain recovery device.

Conventionally, in this type of device, in order to return the drain to the boiler, the head difference between the boiler water level and the drain tank water level has been utilized to push the drain into the boiler casing.

For this purpose, the drain tack must be installed at a higher position than the boiler, which has the disadvantage of making the device large and requiring time to install.

Therefore, in small boilers, the drain tank is placed at the same height as the boiler to avoid this, but steam or compressed air is required as a driving source.

Further, since the drain tank is usually open to atmospheric pressure, even if high temperature drain returns, it is flanched at 100° C. at atmospheric pressure, resulting in a large wasteful heat loss.

The present invention eliminates the above-mentioned drawbacks of the conventional system by inserting a drain tank in series in the water supply line from the water supply pump to the boiler. It is an object of the present invention to provide a drain recovery device that does not require a tank to be placed at a high place and is compact in size.

The present invention is provided with a water tank, a water supply pump, a drain tank, a boiler, and the following yarn paths (4), (B), (C), 0, and (E), and the water in the drain tank is transferred to the water supply pump. A drain recovery device characterized in that the drain is sent to the boiler.

(4) A water supply pump line that leads water from the water tank to the drain tank via the water supply pump.

(B) A drain replenishment line that leads water from the drain tank to the boiler via a check valve.

(C) A steam line that leads steam from the boiler to the load.

Q)) A drain return line that leads condensed water from the load to the drain tank via a check valve.

(E) A regulating circuit that leads excess steam and/or water from the drain tank to the water tank via a valve mechanism that opens when the water supply pump stops and ensures that the inside of the drain tank is at a predetermined minimum pressure or higher. be.

The present invention will be described with reference to the drawings. In FIG. 1, 1 is a water supply pump, 2 is a drain tank, 3 is a boiler, 4 is a load, and 5 is a soft water tank.

6 is a suction pipe. A water supply pump system line is formed by the pipes 6, 7, 8 and the check valve 9, and the pipe 10° 11 and the check valve 12
A drainage/resupply thread path is formed by the pipes 13 and 14.
, a steam line is formed by the valve 15, and the pipes 16, 17,
18, a steam trap 19 and a check valve 20 form a drain return line, and a regulating line is formed by pipes 21, 22, 23, and two valves, a solenoid valve 24 and a pressure regulating valve 25. A pressure adjustment system is formed.

26 is a pressure detector that detects the pressure inside the drain tank 2;
27 is a water level detector that detects the water level of the boiler.

The water level detector 27 detects the water level relative to the maximum set water level and the minimum set water level, and sends a signal to start the water supply pump 1 if the water level falls below the minimum set water level, and to stop the water supply pump 1 if the water level attempts to exceed the maximum set water level. It's about to come out.

Additionally, the solenoid valve 24 is designed to remain open while the water supply pump 1 is stopped, as shown in FIG.

The pressure regulating valve 25 is set to a predetermined minimum pressure (in order to obtain high-temperature drain, the minimum pressure should be as high as possible, but if it is too high, the drain from the load 4 will not return to the drain tank 2, so there is a limit).

) is secured in the drain tank 2.

The electromagnetic valve 24 and the pressure regulating valve 25 form a valve mechanism that opens when the water supply pump 1 is stopped and maintains the inside of the drain tank 2 at a predetermined minimum pressure or higher.

During steady operation of the boiler 3, the water level is between the highest and lowest levels, the feed pump 1 is stopped, and therefore the solenoid valve 24
is open, and the pressure inside the drain tank 2 becomes the lowest pressure (higher than atmospheric pressure) set by the pressure regulating valve 25, and the drain flows into the drain tank 2 through the steam trap 19.

The drain and the hot water already in the drain tank 2 exchange heat, and the water in the drain tank 2 reaches the saturation temperature of the set pressure.

Excess steam and/or surplus hot water generated at this time is returned to the soft water tank 5 via the electromagnetic valve 24 and the pressure regulating valve 25.

This soft water tank 5 also exchanges heat between the excess steam, hot water, and the water already in it, but since it is open to the atmosphere, 1
The water will be hot below 00℃.

When the boiler 3 continues to operate and the water level in the boiler 3 is about to drop below the minimum set water level, the water level detector 27 issues a signal to start the feed water pump 1, the solenoid valve 24 closes according to the sequence, and the water pump 1 discharges. Due to the pressure, the saturated water in the drain tank 2 that reaches the set pressure is pushed out of the drain tank 2 and enters the cone of the boiler 3.

When the water level in the boiler 3 reaches the highest set water level, the feed pump 1 is stopped by a signal from the water level detector 27, the solenoid valve 24 is opened, and the above-mentioned state is established, and the cycle is repeated.

Fig. 3 shows a sequence applied to another embodiment, in which a pressure detector 26 provided in the drain tank 2 is used to maintain the minimum pressure so that the pressure inside the drain tank 2 does not fall below a certain minimum setting pressure, and the water supply The pump 1 is started and stopped by a signal from the water level detector 27 as in the above example.

In this case, a variable or fixed orifice may be used instead of the pressure regulating valve 25.

In the above embodiment, the water supply pump 1, drain tank 2, and boiler 3 are connected in series, and the discharge pressure of the water supply pump 1 is used to replenish drain to the boiler 8.
There is no need to place the drain tank 2 higher than the boiler 3, and the entire device becomes smaller and the installation work becomes easier.

Further, since the pressure in the drain tank 2 is not released to atmospheric pressure and is maintained at a certain pressure, wasteful loss of heat from the high-temperature drain can be prevented.

Furthermore, the inside of the drain tank 2 is brushed under a set pressure, and the dissolved oxygen in the water is also flushed and vaporized, which is then discharged along with the steam to the soft water tank 5 via the solenoid valve 24.
Since this is done when the feed water pump 1 is stopped, oxygen is not sent to the boiler 3 again, so that a deaeration effect can be achieved.

Moreover, the pressure regulating valve 25 is not used as a valve of the regulating circuit,
Only the solenoid valve 24 may be provided.

Even in this case, the discharge pressure of the water supply pump 1 can be used to return the drain to the boiler 3, and the drain tank 2 does not need to be placed at a high place.

According to the present invention, it is possible to provide a drain recovery device which does not require installing the drain tank at a higher place than the boiler, the entire device is small, and the installation work is simple and easy, and has an extremely significant practical effect.

[Brief explanation of the drawing]

The drawings show embodiments of the invention, with FIG. 1 being a flow diagram and FIG.
The figure is a part of a sequence diagram, and FIG. 3 is a part of a sequence diagram of another embodiment. 1... Water supply pump, 2... Drain tank, 3...
Boiler, 4...Load, 5...Soft water tank, 6...
Suction pipe, 7... Piping, 8... Piping, 9... Check valve, 10... Piping, 11... Piping, 12... Check valve, 13... Piping, 14 ...Piping, 15...Valve, 1
6... Piping, 17... Piping, 18... Piping, 19
...Steam trap, 20...Check valve, 21...
・Piping, 22...Piping, 23...Piping, 24...
Solenoid valve, 25...pressure adjustment valve, 26...pressure detector, 27...water level detector.

Claims (1)

[Scope of Claims] 1. A water tank, a water supply pump, a drain tank, a boiler, and the following yarn paths (4), (B), (C), [)) and C) are provided, and the water in the drain tank is A drain recovery device characterized in that the water is sent to the boiler by the water supply pump. (4) A water supply pump line that leads water from the water tank to the drain tank via the water supply pump. (B) A drain replenishment line that leads water from the drain tank to the boiler via a check valve. (C) A steam system line that leads steam to the load of the boiler. 0 A drain return path that leads condensed water from the load to the drain tank via a check valve. Excess steam and/or water is transferred from the drain tank to the water tank via a valve mechanism that opens when the water supply pump is stopped and ensures that the inside of the drain tank is at a predetermined minimum pressure or higher.
Or a regulating circuit that directs water. 2. The device according to claim 1, wherein the valves in the regulating circuit are electromagnetic valves and pressure regulating valves.