JPS6160321B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drain recovery device used for recovering condensate generated in a steam-using device to a boiler. More specifically, the present invention relates to a drain recovery device used when a drain recovery line joins a water supply line and condensate is force-fed to a boiler using a water supply pump.

A tank is generally placed at the confluence of the drain recovery line and the water supply line, and the drain recovery line often rises toward the tank. When the water supply pump is started and the water in the tank is pumped, condensate is likely to be preferentially sucked in due to the water head difference, and the water temperature inside the water pump increases, causing problems such as cavitation and erosion, which makes the pump unable to pump water. There is a problem that the product becomes unusable due to burn-in or burn-in. In addition, there are systems that are configured so that the water supply always flows to the water supply pump to prevent the inhalation of the high-temperature water mentioned above, but most of these systems are configured so that water is supplied regardless of whether the water supply pump is running or stopped. However, there was a problem with using more water than necessary.

The present invention aims to solve the above-mentioned problems, and aims to provide a drain recovery device that starts water supply from the water supply line every time the water supply pump is operated, allows the water supply pump to operate safely, and uses the water supply efficiently. It is something.

Next, the present invention will be explained in detail based on illustrated embodiments.

First, the outline of the drain recovery device and piping according to the embodiment of the present invention shown in FIG. 1 will be explained. The steam generated in the boiler 1 is sent to the steam-using equipment 3 through the transport pipe 4, and the condensate generated there is discharged from the steam trap 5 and passes through the drain recovery pipe 6 to the tank 12.
is led to the upper chamber 13. The upper part of the upper chamber 13 is connected to the porous dispersion plate 18 at the lower part of the lower chamber 14 through the communication pipe 16.
It communicates below. The lower chamber 14 is an overflow pipe 1
5 to the atmosphere, and supplementary water from the water supply pipe 7 is automatically supplied through the ball tap 23. Upper chamber 1
A drain pipe 17 opened at the bottom of the lower chamber 3 and a water pipe 20 opened at the bottom of the lower chamber 14 and connected to a check valve CK1 join the absorption pipe 10 to the pump 2. A discharge pipe 22 from the pump 2 is connected to the boiler 1 via check valves CK2 and CK3.

A bypass pipe 8 is provided from the water supply pipe 7 to the suction pipe 10, and a solenoid valve SV1 and a throttle means 9 are interposed therebetween. A solenoid valve SV2 is arranged in the exhaust pipe 19 from the water supply pump 2.

The drain recovery device described above can be controlled using the circuit shown in FIG. Next, the circuit will be explained.

Terminals U, V, and W are connected to a power source via a level switch that opens and closes depending on the liquid level in the boiler 1. Terminals U', V', and W' are connected to pump 2. Terminal T,
Connect R to the power supply. PB1 is the start switch, PB
2 is a stop switch, SV1 and SV2 are solenoid valves, MC
is an electromagnetic relay, X1, X6, X7 are relays, T1
means a timed switch that turns on after a set time.

Next, the operation of this apparatus will be explained according to the time chart shown in FIG. Here, PUMP means pump 2, t1 to t7 mean time, and other symbols correspond to the same symbols in FIGS. 1 and 2. In addition, a high level of the time chart indicates that the valve is open, relay terminal X1 is connected, and the pump is operating; a low level indicates that the valve is closed, and relay terminal
1 indicates the open state and the pump is in the stopped state.

First, the time switch T1 is set to turn on after a predetermined time T2-T1. Next, press the push button type start switch PB1 and the relay
1 is energized, relay terminal X1 is held closed, and the circuit is connected to the power source.

Time switch T1 is OFF and relay X7 is deenergized. Therefore, electromagnetic valves SV1 and SV2 are energized and open, and electromagnetic relay MC is deenergized and terminal MC is open, so pump 2 is prohibited from operating. At this time, the water supplied from the water supply pipe 7 enters the pump 2 through the bypass pipe 8 and is primed into the pump 2. Further, the air in the pipes 8 and 10 and the pump 2 is expelled to the outside through the exhaust pipe 19.

When the set time has passed and time t2 has passed, time limit switch T1 is turned ON, and relay X7
is energized. Furthermore, since the electromagnetic relay MC is energized, the contact MC is closed and current supply to the pump 2 is allowed. At the same time, the solenoid valve SV2 becomes closed.

In this state, if the level switch of the boiler 1 is closed at time t3, the terminals U, V, and W are connected to the power supply, and the pump 2 is started. tank 1
The make-up water in the lower chamber 14 of 2 passes through the water pipe 20 and the suction pipe 10, enters the pump 2, and is sent under pressure to the boiler 1 through the discharge pipe 22. At this time, relay X6 is energized and terminal X6 is closed, so that solenoid valve SW1 is opened. The make-up water in the water supply pipe 7 passes through a bypass pipe 8 and is controlled by throttling means 9, and a small amount is sucked into the pump 2 through a suction pipe 10. When the boiler 1 is sufficiently supplied with water and the level switch is opened at time t4, the operation of the pump 2 is stopped and at the same time, the relay X6 is deenergized, so that the solenoid valve SW1 is closed.

The high temperature condensate is led to the upper chamber 13 of the tank 12 through the recovery pipe 6 and is collected there. The upper steam is led to the lower part of the lower chamber 14 through the communication pipe 16 and is slowly absorbed into the low temperature feed water through the pores of the dispersion plate 18. The upper chamber 13 is maintained at approximately atmospheric pressure through the lower chamber 14, so that the discharge action of the steam trap 5 is not hindered.

When the level switch of boiler 1 is closed at time t5, pump 2 is started in the same manner as described above. At this time, relay X6 is in the energized state, and solenoid valve SV
1 is energized and becomes open. The condensate in the upper chamber 13 has a head difference with respect to the water supplied in the lower chamber 14, and is sucked into the pump 2 with priority over the supplied water. Supplying low-temperature water through the bypass pipe 8 is effective against concerns about an increase in intake water temperature and the occurrence of cavitation due to preferential suction of condensate. Therefore, the pump 2 can be safely operated without causing cavitation, and the condensate can be pumped to the boiler 1.

When the level switch of boiler 1 is opened at time t6, operation of pump 2 is stopped, relay X6 is deenergized, and solenoid valve SV1 is closed.

Thereafter, the solenoid valve SV1 is opened every time the pump 2 is operated to supply water.

To stop the device, use a push-button stop switch.
This is done by pressing PB2 (time t7). That is, this deenergizes relay X1, opens contact X1, and disconnects the circuit from the power source.

In this way, the drain recovery device of the present invention supplies low-temperature feed water to the suction side of the pump each time the water pump is operated, and the water pump preferentially sucks condensate to increase the water temperature inside the pump. It is possible to prevent cavitation from occurring. Furthermore, since water is supplied only when the water pump is in operation, the water supply is not wasted.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a drain recovery device and attached piping according to an embodiment of the present invention, Fig. 2 is an example of a control circuit of the embodiment shown in Fig. 1, and Fig. 3 is a timing diagram showing the operating state of this embodiment.・It is a chat. 1: Boiler, 2: Water supply pump, 6: Drain recovery pipe, 7: Water supply pipe, 8: Bypass pipe, 9: Squeezing means, 12: Tank, T1: Time switch, SV
1. SV2 is a solenoid valve.

Claims (1)

[Claims] 1. When a drain recovery line joins the water supply line to the boiler and condensate is recovered to the boiler through the water supply pump, a bypass pipe is provided that branches from the water supply line to the suction side of the water supply pump, and the water supply pump is connected to the bypass pipe. A drain recovery device characterized by having a valve means that opens simultaneously with the operation of the drain recovery device.