JPH06241413A - Steam supply/recovery apparatus - Google Patents

Abstract

PURPOSE:To obtain a steam supply/recovery apparatus which enables surely and quickly the discharging of a condensate to the outside when the water level of the condensate in a condenser tank reaches a specified value while useless consumption of steam and a drop in the suction capacity are suppressed in the normal operation. CONSTITUTION:A stationary control means 30 is provided to perform a proportional control of the number R1 of a pump 15 in an ejector type suction/force feed apparatus 6 normally corresponding to a water level L1 of a condensate 5a of a gas/water separation tank 5 and a forcible discharge means 32 which opens a discharge valve 8 to discharge the condensate in the condenser tank 14 outside while rotating the pump 15 at the number R2 of revolutions higher than that in the normal operation when the water level L2 of the condensate W in the condenser tank 14 reaches a specified value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to heating paints and foods, for example, and uses the latent heat of vacuum steam to generate steam for heating various temperatures below 100.degree. The present invention relates to a steam supply / recovery device that supplies this to a load for consumption of steam heat, and more specifically, suctions the condensate side of a steam separation tank that separates steam that has passed through the load and condensate and The present invention relates to a technique for controlling the pump rotation speed of a suction device that sends water to a condensate tank.

[0002]

2. Description of the Related Art In this type of vapor supply and recovery system,
The pump incorporated in the ejector-type suction device for sucking the secondary side of the pressure reducing valve is constantly operated at the rated speed to suck the condensed water that has passed through the load. Here, the rated operation of the pump is an operation under a rotational speed at which the liquid in the condensate tank can be pumped to the outside such as a recovery tank by the discharge pressure of the pump. However, since steam is mixed in the condensed water that has passed through the load, the steam flows into the suction device. That is, the steam is wasted. Therefore, the applicant of the present invention first provided a steam separation tank between the load and the ejector type suction device, and the condensate side of this steam separation tank was
A technique has been proposed to prevent the inflow of steam into the ejector type suction device as much as possible by sucking the suction device with a suction force according to the water level of the condensate (Japanese Patent Application No. 4-158).
573).

[0003]

By the way, in this type of steam supply and recovery apparatus, the condensate sucked from the steam-water separation tank by the ejector type suction apparatus flows into the condensate tank, and its water level is set to a predetermined level. When the value exceeds the value, it is necessary to open the discharge valve and discharge the condensate in the condensate tank to an external recovery tank. Even in this case,
In the technology previously proposed by the applicant, the pump is proportionally controlled according to the condensate water level in the steam separation tank, regardless of the water level in the condensate tank, and at a low rotation speed. Since it is driven, the condensate in the condensate tank cannot be reliably and quickly discharged to the outside.

The present invention has been made in view of the above situation, and when the water level in the condensate tank exceeds a predetermined value while reducing wasteful consumption of steam and reduction of power consumption, It is an object of the present invention to provide a steam supply / recovery device capable of reliably and quickly discharging condensed water in a water tank to the outside.

[0005]

In order to achieve the above-mentioned object, a steam supply and recovery apparatus according to the present invention comprises a pressure reducing valve for reducing the pressure of high pressure steam on the primary side and flowing it to the secondary side, and a secondary side. A steam-water separation tank that separates steam and condensate that have passed the load that uses the latent heat of steam, and a vacuum is generated by a pump to suck the condensed water side of the steam-water separation tank, and the suctioned condensate An ejector-type suction / pressure-feeding device for sending the condensed water in the condensate tank to the outside by the pump, a discharge valve for opening / closing the discharge-passage, and the ejector-type suction / pressure-feeding device. In order to prevent vapor from being sucked from the steam / water separation tank, steady control means for controlling the number of revolutions of the pump in accordance with the level of condensed water in the steam / water separation tank, and condensed water in the condensate tank. The water level has risen to a certain level At this time, the pump is rotated at a higher rotation speed than the control by the steady control means, the discharge valve is opened, and the forced discharge means for discharging the condensed water in the condensed water tank to the outside is provided. .

[0006]

According to the present invention, normally, steam is not sucked from the water / water separation tank by the steady control means in accordance with the rotational speed of the pump of the ejector type suction device in accordance with the condensate water level in the water / water separation tank. By performing steady operation while controlling the rotation speed to such a low value, it is possible to eliminate wasteful consumption of steam due to suction of the steam in the steam separation tank by the pump of the ejector suction device, While suppressing the decrease in capacity, only when the condensate water level in the condensate tank rises and reaches a predetermined value, the pump discharge speed is increased by the forced discharge control means and the discharge valve is opened. Condensed water in the condensate tank can be reliably forcibly discharged to the outside such as the recovery tank in a short time. When the water level of the condensate in the condensate tank returns to a predetermined value or less due to this forced discharge, the pump speed is returned to the low speed during steady operation described above to reduce wasteful consumption of steam and power consumption. It can be minimized.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram of a steam supply apparatus according to an embodiment of the present invention, in which 1 is a steam supply pipe,
Reference numeral 2 is a steam control valve for opening and closing the steam supply pipe 1, and 3 is a vacuum pressure reducing valve for reducing the pressure of the high pressure steam on the primary side and flowing it to the secondary side. Reference numeral 4 denotes a steam consumption load for heating an object to be heated by utilizing latent heat of steam on the secondary side, 5 denotes a steam water separation tank provided downstream of the steam consumption load 4 for separating steam and condensate, and 6
Is an ejector-type vacuum suction / pressure feeding device, 7 is a condensate discharge passage, 8 is a condensate discharge valve, 10 is a recovery pipe that connects the steam consumption load 4 and the steam separation tank 5, 11 is a controller,
Reference numerals 17 and 18 are separators, and 19 is a desuperheater.

The ejector type suction / pressure feeding device 6 includes an ejector 13 for sucking the condensate side 5a of the steam separation tank 5 through a pipe 12, and a condensate tank 14 into which the condensate sucked by the ejector 13 is sent. A pump 15 for sucking the water W in the condensate tank 14 from the bottom of the tank 14 and increasing the pressure to generate a jet flow of the ejector 13, and then sending the water together with the condensate to the condensate tank 14. The pump 15 is variably controlled in rotation speed by the inverter 16 based on the control signal CS from the controller 11.

The water / water separation tank 5 is provided with a level sensor 22 for detecting the water level L1 of the condensed water 5a therein. Further, the condensate tank 14 is provided with a level sensor 23 for detecting the water level L2 of the condensate W therein.

The controller 11 includes detection signals S1 (L1) and S2 from the level sensors 22 and 23.
(L2) is input respectively. In addition, as shown in FIG.
Corresponding to the water level L1 of the condensate 5a in the steam separation tank 5 according to the detection signal S1 from 2, the pump 15 in the ejector suction / pressure feeding device 6 is rotated via the inverter 16 in proportion to the water level L1. The steady control means 30 for controlling the number R1 and the water level L2 of the condensate W in the condensate tank 14 by the detection signal S2 from the level sensor 23 have reached a preset high level H (predetermined value). When
Rotational speed R2 higher than the control by the steady control means 30
The pump 15 is rotated and the discharge valve 8 is opened to forcibly discharge the condensed water W in the condensed water tank 14 to an external recovery tank 40 or the like. In the case of the present embodiment, the rated speed of the pump 15 is adopted as the high speed of the pump 15. The steady-state rotation speed R1 refers to the rotation speed of the pump in a normal range in the proportional control, that is, when the water level L1 of the steam separation tank 5 is between a predetermined high level and a predetermined low level.

FIG. 2 is a block diagram showing a specific configuration of the steady control means 30 and the forced discharge means 32 in the controller 11. In the figure, 25A, 25
B is a first and a second comparator, of which the first comparator 25A is a water level L2 detected by the level sensor 23.
And the high level H (predetermined value) of the water level preset for the condensate tank 14 are compared, and the signal Sa is output when the detected water level L2 is higher than the high level H. The second comparator 25B compares the water level L2 detected by the level sensor 23 with the low level L of the water level preset for the condensate tank 14, and the detected water level L2 becomes equal to or lower than the low level L. Signal Sb is output.

A latch circuit 26 outputs a control signal Ca for opening from the output terminal OUT to the discharge valve 8 when the output signal Sa from the first comparator 25A is input to the set terminal S thereof. . When the output signal Sb from the second comparator 25B is input to the reset terminal R of the latch circuit 26, the output of the opening control signal Ca is reset.

Reference numeral 28 is a signal selector circuit. In the selector circuit 28, the water level L detected by the level sensor 22 for detecting the water level L1 on the side of the condensate 5a in the water / water separation tank 5.
Corresponding to No. 1, the rated operation in which the proportional control signal C1 output from the proportional control circuit 30A forming a part of the steady control means 30 forms a part of the forced discharge means 32 at the first input terminal IN1. (Full operation) The rated operation control signal C2 output from the control circuit 32A is input to the second input terminal IN2, and the control signal C for the pump 15 is
As S, the proportional control signal C1 is normally output from the output terminal OUT, and the latch circuit 2 is connected to the select terminal S.
When the output signal Ca from 6 is input, the output terminal OU
The rated operation control signal C2 is output from T.

In the steam supply / recovery apparatus constructed as described above, during normal operation, steam is supplied to the load 4 through the steam control valve 2, the vacuum pressure reducing valve 3 and the steam supply pipe 1, and the load 4 The steam from which the latent heat is released becomes condensed water and enters the steam separation tank 5 from the recovery pipe 10 together with a part of the steam that has not condensed. Condensed water 5a in the steam separation tank 5 is sucked by the ejector-type suction / pressure feeding device 6 and fed into the condensed water tank 14. Regarding the peculiar operation according to the present invention that is performed during such normal operation,
This will be described with reference to the timing chart of FIG.

That is, with the start of operation, the water level L1 of the condensate 5a in the steam-water separation tank 5 and the condensate tank 1
The water level L2 of the condensate W in 4 is the level sensors 22 and 23.
Are detected by the detection signals S1 (L1), S2
(L2) is input to the controller 11, respectively. Then, as shown in FIG. 3A, when the detected water level L2 is smaller than the high level H, that is, during normal operation,
Since the signal Sa is not output from the first comparator 25A,
From the output terminal OUT of the selector circuit 28, the pump 15
As the control signal CS for, the proportional control signal C1 as shown in FIG. 3C input to the selector circuit 28 via the proportional control circuit 30A is output. As a result, the pump 15 is in a steady operation state in which the rotational speed R1 is proportional to the fluctuation of the water level L1 of the condensate 5a of the steam / water separation tank 5 as shown in FIG. The steam in the tank 5 is prevented from being sucked by the ejector type suction / pressure feeding device 6 and wasted, and the suction capability of the ejector 13 is prevented from being lowered.

In such a steady operation state, when the detected water level L2 of the condensed water W by the level sensor 23 becomes higher than the high level H (h1 in FIG. 3 (a)), the first comparator 25A outputs Output signal Sa of latch circuit 26
Input to the set terminal S of the
A control signal Ca for opening is output from the UT to the discharge valve 8, and the discharge valve 8 is opened as shown in FIG. 3 (b). At the same time, the control signal Ca from the output terminal OUT of the latch circuit 26 is input to the input terminal S of the selector circuit 28. As a result, the output terminal O of the select circuit 28
As shown in FIG. 3C, the rated operation control signal C2 in the forced discharge means 32 is output from the UT as the pump control signal CS, so that the pump 15 is higher than the rotational speed R1 in the steady operation state described above. Condensed water W in the condensate tank 14 becomes the rated operating state in which it is controlled to a high rated speed R2.
Is forcibly and rapidly discharged through the discharge passage 7 to the external recovery tank 40 or the like.

When the condensate is forcibly discharged as described above, the detected water level L2 in the condensate tank 14 is gradually lowered, and the detected water level L2 by the level sensor 23 is lowered to a predetermined low level L or less. (H in FIG. 3 (a)
2), the output signal Sb from the second comparator 25B is input to the reset terminal R of the latch circuit 26, and the output of the control signal Ca is reset. As a result, the discharge valve 8 is closed as shown in FIG. 3 (b), and the output terminal OUT of the select circuit 28 outputs the proportional control signal C as shown in FIG. 3 (c) as the pump control signal CS.
1 is output. As a result, the pump 15 is
As shown in (d), the steady operation state is controlled in which the rotational speed R1 is controlled in proportion to the fluctuation of the water level L1 of the condensed water 5a of the steam separation tank 5.

Therefore, in the rated operation state, the water level of the steam / water separation tank 5 becomes zero level, and a large amount of steam is sucked through this steam / water separation tank, and the steam is wastefully consumed. The time is extremely short, and wasteful consumption of steam can be significantly reduced as compared with the conventional case in which the pump 15 is constantly operated in the rated operation state.

As the pump rotation speed R2, a rotation speed lower than the rated rotation speed may be selected unlike the above embodiment.

[0020]

As described above, according to the present invention, in normal times, the steady control means operates the pump of the ejector type suction / pressure feeding device by controlling the rotation speed of the pump to a low rotation speed to operate the steam-water operation. It is possible to avoid wasteful consumption of steam due to the suction of the steam in the separation tank by the pump, and to suppress a decrease in suction capability that accompanies suction of the steam. On the other hand, when the condensate water level in the condensate tank rises and reaches a predetermined value, the forced discharge control means increases the pump rotation speed and opens the discharge valve.
Condensed water in the condensate tank can be reliably forcibly discharged to the outside such as the recovery tank in a short time. Also,
When the water level of the condensate in the condensate tank falls below a predetermined value due to this forced discharge, the pump speed is returned to the low speed during steady operation described above to reduce wasteful consumption of steam and power consumption. Can be kept to a minimum.

[Brief description of drawings]

FIG. 1 is a system diagram of a steam supply / recovery apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a specific configuration of steady control means and forced discharge means in the controller.

FIG. 3 is a timing chart for explaining a specific control operation of the device.

[Explanation of symbols]

3 ... Vacuum pressure reducing valve, 4 ... Load, 5 ... Steam separation tank, 5a
... Condensate, 6 ... Ejector type vacuum suction / pressure feeding device, 11 ...
Controller, 14 ... Condensate tank, 15 ... Pump, 2
2, 23 ... Level sensor, 30 ... Steady state control means, 32 ...
Forced discharge means.

Claims (1)

[Claims] 1. A pressure reducing valve for reducing the pressure of high-pressure steam on the primary side and flowing it to the secondary side, and a steam separation tank for separating steam that has undergone a load utilizing latent heat of steam on the secondary side and condensate. An ejector-type suction / pressurization device for generating a vacuum by a pump to suck the condensed water side of the steam-water separation tank and sending the sucked condensed water to the condensed water tank; and a pump for recovering the condensed water in the condensed water tank. A discharge passage that discharges water to the outside, a discharge valve that opens and closes this discharge passage, and a condensate of water inside the steam-water separation tank so that steam is not sucked from the steam-water separation tank by the ejector suction / pressure feeding device. A steady control means for controlling the rotation speed of the pump in accordance with the water level, and a rotation speed higher than the control by the steady control means when the water level of the condensate in the condensate tank rises and reaches a predetermined value. Rotate the above pump with A steam supply and recovery device having a forced discharge means for opening the discharge valve and discharging the condensate in the condensate tank to the outside.