JPH06100314B2 - steam trap - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a steam trap for mainly discharging condensed steam, that is, drain discharged from a device using steam.

<Prior Art> Generally, the steam trap described above is one in which the drain discharged from a steam using device such as a heat exchanger is intermittently discharged by alternately repeating opening and closing of the valve. It is classified into mechanical traps, thermostatic traps, thermodynamic traps, etc. In a thermostatic trap, the temperature of the drain accumulated immediately before the trap during the valve closing period drops, and when the temperature of this drain drops to a certain temperature, the valve opens, which raises the temperature of the drain and increases the temperature of the drain. When the temperature rises to some other temperature, the valve closes repeatedly. The operating principles of mechanical traps and thermodynamic traps are different from the above-mentioned principles, but from a phenomenological point of view they are no different from thermostatic traps. However, it is considered that the drain temperature or supercooling degree (difference between the temperature t _{S of the} steam supplied to the steam using device and the temperature of the drain) at the time of opening / closing valve is different only depending on the type and type of the trap.

<Problems to be Solved by the Invention> As described above, in terms of operation phenomenon, although there is no great difference between traps, the configuration of each trap is largely different depending on its operating principle. There is a problem in that the manufacturing of the structure has to be performed and the manufacturing is troublesome. In addition, there is a problem that the user is confused about which trap to use when using the trap.

This invention has been made in view of the above problems,
It is an object of the present invention to provide a steam trap that has a simple trap structure and is easy to select and manufacture.

<Means for Solving the Problem> In order to achieve the above-mentioned object, the invention according to claim 1 is an on-off valve which is provided on the discharge side of a steam using device and which is opened and closed according to a control signal, and a steam using device. The steam temperature measuring means for measuring the temperature of the steam supplied to the steam using device, and the discharge temperature measuring means for measuring the temperature of the installation position provided on the supply side of the on-off valve, It has.

Further, a valve-opening supercooling degree signal indicating the degree of supercooling when opening the opening / closing valve and a valve closing supercooling degree signal indicating the degree of subcooling when closing the opening / closing valve are stored. Storage means, means for generating a supercooling degree signal based on signals from the steam temperature measuring means and the discharge temperature measuring means, and opening / closing when the supercooling degree signal becomes larger than the on / off valve supercooling degree signal. A control signal generating means is provided for supplying an opening control signal to open the valve and supplying a closing control signal to close the opening / closing valve when the supercooling degree signal becomes smaller than the closing supercooling degree signal. .

The invention according to claim 2 is the same as the invention according to claim 1,
An opening / closing valve, a steam temperature measuring means, and a discharge temperature measuring means, and further a storage means for storing a valve closing supercooling degree signal representing a degree of subcooling when closing the opening / closing valve, A means for generating a supercooling degree signal based on signals from the steam temperature measuring means and the discharge temperature measuring means, and a supercooling degree signal when the opening control signal is supplied to the on-off valve Control signal generating means for supplying a close control signal to the open / close valve when the signal becomes smaller than the frequency signal, and an open control signal generation for supplying an open control signal to the open / close valve after a lapse of a predetermined time after the close control signal is generated. And means are provided.

The invention of claim 3 is the same as the invention of claim 2,
A means for measuring the opening time for which the opening control signal was supplied,
A time determining means for determining whether or not the opening time is within a predetermined range, and a changing means for changing the above predetermined time which is the closing time of the on-off valve when the opening time is outside the above range are provided. It is a thing.

The invention according to claim 4 is the same as the invention according to claim 1,
An opening / closing valve, a steam temperature measuring means, and a discharge temperature measuring means, and further a storage means for storing a valve opening supercooling degree signal representing a degree of supercooling when the opening / closing valve is opened, A means for generating a supercooling degree signal based on signals from the steam temperature measuring means and the discharge temperature measuring means, and a supercooling degree signal when the closing control signal is supplied to the opening / closing valve. Control signal generation means for supplying an opening control signal to the opening / closing valve when the signal becomes larger than the frequency signal, and a closing control signal generation for supplying a closing control signal to the opening / closing valve after a lapse of a predetermined time after the opening control signal is supplied. And means are provided.

According to a fifth aspect of the present invention, in addition to the fourth aspect of the invention, a means for measuring the closing time to which the closing control signal is supplied, and a time for determining whether or not the closing time is within a predetermined range. The determining means and the changing means for changing the predetermined time which is the opening time of the on-off valve when the closing time is out of the above range are provided.

<Operation> According to the invention described in claim 1, the supercooling degree signal generating means causes the supercooling degree signal generating means to measure the supercooling degree based on the steam temperature measured by the steam temperature measuring means and the drain temperature mainly measured by the discharge temperature measuring means. Generate a signal.

In the valve closed state, the drain stays and the drain temperature decreases, so that the supercooling degree signal generated by the supercooling degree signal generating means increases. When the supercooling degree signal becomes larger than the valve opening supercooling degree signal, the opening control signal is supplied to the opening / closing valve, the opening / closing valve is opened, and the drain is discharged. When the drain temperature rises and the supercooling degree signal decreases while the on-off valve is open, and becomes smaller than the closing supercooling degree signal, the closing control signal is supplied to the on-off valve to close the on-off valve. To be Thereafter, the same operation is performed.

In the invention described in claim 2, in the valve open state, as in the invention described in claim 1, when the drain temperature rises and the supercooling degree signal becomes smaller and becomes smaller than the valve closing supercooling degree signal, The on-off valve is closed. Then, after a lapse of a predetermined time, the open control signal generating means generates the open control signal and forcibly opens the on-off valve regardless of the supercooling degree signal. That is, the valve closing time is made constant.

In the invention described in claim 3, as in the invention described in claim 2, whether or not the actual opening time of the on-off valve is within a predetermined range after the control for keeping the valve closing time constant is performed. Is determined by the time determination means, and if it is out of the range, the valve closing time, which is a constant time, is changed by the changing means.

In the invention according to claim 4, contrary to the invention according to claim 2, when the supercooling degree signal becomes larger than the valve opening supercooling degree signal, the opening / closing valve is opened, and when the predetermined time elapses, The on-off valve is forcibly closed regardless of the degree of cooling. That is, the valve opening time is always constant.

In the invention according to claim 5, as in the invention according to claim 4, whether or not the actual closing time of the on-off valve is within a predetermined range after the control for making the valve opening time constant is performed. Is judged by the time judging means, and if it is out of the range, the opening time, which is a constant time, is changed by the changing means.

<Embodiment> A first embodiment corresponding to the invention described in claim 1 is shown in FIG. 1 and FIG. In FIG. 1, 2 is a steam using device such as a heat exchanger, and saturated steam for heating is supplied through a steam supply valve 4. On the other hand, the fluid to be heated is also supplied to the steam using apparatus 2, and the fluid to be heated is heated by the heat transfer from the steam. The steam that has been transferred by heat to the fluid to be heated and condensed, that is, the drain, is discharged from the steam using device 2 through a pipe, and an electromagnetic opening / closing valve 6 is provided at a predetermined position of the pipe. The on-off valve 6 opens and closes in response to a control signal from the microcomputer 8. The microcomputer 8 has a steam temperature signal obtained from a steam temperature measuring device 10 provided on the steam supply side of the steam using apparatus 2 and a temperature signal obtained from a discharge temperature measuring device 12 provided on the supply side of the on-off valve 6 ( This mainly represents the temperature of the drain, but also represents the temperature of the accumulated air in the pipe. Hereinafter, it will be referred to as the drain temperature signal). To do.

The outline of the control performed by the microcomputer 8 will be described. If the on-off valve 6 is closed now, the drain will stay and the temperature of the drain will drop. As a result, the degree of supercooling δ, which is the difference between the steam temperature and the drain temperature, becomes large. Eventually, the degree of supercooling δ becomes larger than the degree of supercooling δ1 at the time of valve opening, which is predetermined as the degree of supercooling when opening the on-off valve 6. At this time, the microcomputer 8 causes the open / close valve 6
Open the valve and drain the drain. As a result, the drain temperature rises and the supercooling degree δ decreases. Eventually, the degree of supercooling δ becomes smaller than the degree of supercooling δ2 at the time of closing the valve, which is predetermined as the degree of supercooling when the on-off valve 6 is closed. At this time,
The microcomputer 8 closes the on-off valve 6, the drain discharge is stopped, and the drain starts to stay again. As a result, the drain temperature starts to decrease and the degree of supercooling δ increases. Then, as described above, when the degree of supercooling δ becomes larger than the degree of subcooling δ1 at valve opening, the on-off valve 6 is opened. Hereinafter, the above operation is repeated.

FIG. 2 is an operation flowchart of this embodiment. First, the above-described valve-opening supercooling degree δ1 and valve-closing supercooling degree δ2 are
It is stored in the memory in the microcomputer 8 using a keyboard (not shown) (step S2). As is clear from the above description, δ1> δ2.

Following this, the on-off valve 6 is closed (step S4), and the steam temperature t _S and the drain temperature t _C are measured using the steam temperature measuring device 10 and the discharge temperature measuring device 12 (steps S6, 8). ), From t _S
Subcooling degree δ is calculated by subtracting t _C (step S10).
Then, it is determined whether the degree of supercooling δ is greater than the degree of valve opening supercooling δ1 (step S12). If δ is smaller than δ1, the process returns to step S6, until δ becomes larger than δ1.
Repeat steps S6, 8, 10, and 12. That is, the on-off valve 6 maintains the closed state.

Since the drain is retained and the drain temperature is lowered by closing the valve, δ becomes larger than δ1 in due course. At this time, the on-off valve 6 is opened (step S14),
The drain accumulated just before the on-off valve 6 is discharged. Following this, the steam temperature and the drain temperature are measured, and the degree of supercooling δ is calculated in the same manner as above (step S6 ′,
8 ', 10'). Then, it is determined whether or not δ is smaller than the valve closing supercooling degree δ2 (step S16). If δ is larger than δ2, step S is performed until δ becomes smaller than δ2.
Repeat 6 ', 8', 10 'and 16. That is, the valve open state is maintained.

By opening the valve, the drain temperature rises, δ becomes smaller, and eventually becomes smaller than δ2. As a result, step S4 is executed and the valve is closed. Hereinafter, similar to the above, the valve is repeatedly opened when δ becomes larger than δ1, and closed when δ becomes smaller than δ2.

FIG. 3 shows an operation flowchart of the second embodiment corresponding to the invention described in claim 2. Since the apparatus used is the same as that of the first embodiment, detailed description will be omitted. In this embodiment, the valve is closed when the degree of supercooling δ becomes smaller than the degree of supercooling δ2 at the time of valve closing, which is the same as in the first embodiment, but δ is the degree of supercooling at opening δ1. It is not performed when it becomes larger, but is forcibly opened when a predetermined valve closing time Tc elapses after the valve is closed regardless of the degree of supercooling.

That is, first, the valve closing time Tc and the valve closing supercooling degree δ2 are set by the keyboard and stored in the memory in the microcomputer 8 (steps S18, 20).

Next, the on-off valve 6 is opened (step S22), and the steam temperature t
_{The S} and drain temperatures t _C are measured (steps S24 and 26), and the supercooling degree δ is calculated (step S28). Then, it is judged whether or not the supercooling degree δ is smaller than the valve closing supercooling degree δ2 (step S30). If δ is larger than δ2, steps S24, 26 and 28 are repeated until it becomes smaller. That is, the valve open state is maintained.

Since the valve is open, the drain temperature rises and the degree of supercooling δ gradually decreases. Eventually, when δ becomes smaller than δ2, the valve is closed (step S32), waiting for the closing time Tc to elapse (step S34), and then step S22 is executed to open the valve. That is, after the valve closing time Tc has elapsed since the valve was closed, the valve is opened regardless of the degree of supercooling δ. After the valve is opened, the valve is closed when δ becomes smaller than δ2 in the same manner as described above, and is opened when the valve closing time Tc elapses.

FIG. 4 shows an operation flowchart of the third embodiment corresponding to the invention described in claim 3. This embodiment is a modification of the second embodiment, and when the valve opening time is lengthened or shortened due to a change in the load of the steam using device 2,
The valve closing time Tc is corrected to cope with the load fluctuation.

That is, in the second embodiment, after step S34, the valve is opened (step S22 ') without returning to step S22, the steam temperature t _S and the drain temperature t _C are measured, and the degree of supercooling δ is calculated. , Δ is smaller than δ2 (step S2
4 ', 26', 28 ', 30'). Then, steps S24 ', 26', 28 ', 30' are repeated until δ becomes smaller than δ2. Then, when δ becomes smaller than δ2, the valve is closed (step S32 '). Next, the valve opening time To is measured (step S36). This can be done, for example, by causing a counter (not shown) to start counting a clock having a constant frequency when the valve is opened in step S22 ', and when the valve is closed in step S32', the counting is stopped and the count value is read. It

Then, it is determined whether or not this valve opening time To is shorter than a predetermined time, for example, 1/2 of the valve closing time Tc initially set (step S38). If it is short, the degree of supercooling is too small for the valve closing time Tc, so it is necessary to lengthen the valve closing time Tc to increase the degree of supercooling. However, since it cannot be lengthened indiscriminately, the limit of 100 seconds is set in this embodiment. That is, it is determined whether the value obtained by multiplying the current valve closing time by 1.2 is shorter than 100 seconds (step S40), and if it is shorter, the new valve closing time is set to 1.2 times the current valve closing time (step S42). Wait for a new valve closing time Tc (step S44), and then execute step S22 'to open the valve. Further, if the value obtained by multiplying the current valve closing time by 1.2 times is 100 seconds or more (the answer in step S40 is NO), the valve closing time cannot be extended any further, so the current valve closing time Tc
Do not modify, execute step S44 as it is, and
After waiting only for a while, step S22 'is executed to open the valve.

If the valve opening time To is 1/2 or more of the valve closing time Tc (NO at step S38), the valve opening time To is a predetermined time,
For example, it is determined whether it is longer than 1.5 times the valve closing time Tc initially set (step S46). If the valve closing time Tc is too long, the degree of supercooling δ is too large at the current valve closing time Tc.
Is required to be small, and the degree of supercooling δ needs to be small. However, since it cannot be shortened indiscriminately, a limit of 10 seconds is set in this embodiment. That is, the current valve closing time
It is determined whether 0.8 times t _C is greater than 10 seconds (step S4
8) If it is large, the valve closing time can be shortened still, so 0.8 times the current valve closing time t _C is set as the new valve closing time Tc (step S5
0), step S44 is executed to wait for a new valve closing time Tc, and then step S22 'is executed to open the valve. If 0.8 times the current valve closing time Tc is less than 10 seconds (NO at step S48), the valve closing time Tc cannot be shortened any more, so the current valve closing time is not corrected. ,
After executing step S44 and waiting for the current valve closing time Tc, step S22 'is executed to open the valve.

If the valve opening time To is shorter than 1.5 times the valve closing time Tc (NO at step S46), the answer at step S38 is already NO, so the current valve closing time Tc is equal to the valve closing time Tc. 0.5 times and 1.5
It is in the middle of the time, and there is no point in fixing any modifications. Therefore, step S44 is executed with the current valve closing time left, and after waiting for the current valve closing time Tc, step S22 'is executed to open the valve. Hereinafter, the above operation is repeated. If the valve closing time Tc is increased 0.8 times or 1.2 times only once, the valve opening time To does not become less than 1/2 of the valve closing time Tc initially set, or the valve closing time T Tc
Corrected valve closing time is 0.8
Doubled or 1.2 times. While repeating this, the valve opening time To becomes 0.5 to 1.5 times the valve closing time Tc initially set.

FIG. 5 shows an operation flowchart of the fourth embodiment corresponding to the invention described in claim 4. In this embodiment, when the degree of supercooling δ becomes larger than the degree of supercooling δ1 at the time of opening the valve,
Although the same as the first embodiment, the valve is not closed when δ becomes smaller than the closed supercooling degree δ2, but a predetermined valve opening time To is opened regardless of the supercooling degree. When is passed, the valve will be closed compulsorily.

That is, first, the valve opening time To and the valve opening supercooling degree δ1 are set by the keyboard and stored in the memory in the microcomputer 8 (steps S52 and S54).

Next, the on-off valve 6 is opened (step S56), and the steam temperature t
_{The S} and drain temperatures t _C are measured (steps S58, 60) and the degree of supercooling δ is calculated (step S28). Then, it is determined whether or not the supercooling degree δ is smaller than the valve-opening supercooling degree δ1 (step S64). If δ is larger than δ1, steps S58, 60 and 62 are repeated until it becomes smaller. That is, the valve open state is maintained.

Since the valve is open, the drain temperature rises and the degree of supercooling δ gradually decreases. Eventually, when δ becomes smaller than δ1, the valve is closed (step S66). Then, the steam temperature t _S and the drain temperature t _C are measured again (steps S68, 70),
The degree of supercooling δ is calculated (step S72). Then, it is judged whether or not the supercooling degree δ is larger than the valve-opening supercooling degree δ1 (step S74). If δ is smaller than δ1, steps S66, 68, 70, 72, 74 are repeated until it becomes larger. . That is,
Keep the valve closed. Since the valve is closed, the drain temperature decreases and the supercooling degree δ increases. Eventually, when the degree of supercooling δ becomes larger than the degree of subcooling δ1 at valve opening, the valve is opened (step S76), the opening time To is awaited (step S78), and then step S66 is executed. Close the valve. That is, when the valve opening time To has elapsed since the valve was opened, the valve is forcibly closed. After closing the valve, δ is δ
When it becomes larger than 1, the valve is opened, and when the valve opening time To has elapsed, the valve is closed again.

Also in this embodiment, as in the third embodiment, the valve closing time becomes long due to the load variation of the steam using device 2,
When the time becomes short, the valve opening time To can be corrected to cope with the load fluctuation. In this case, step S34 to step S78 in the operation flowchart of FIG.
Change step S22 ′ to “close valve”, change step S30 ′ to “determine whether δ is greater than δ1” similarly to step S74, and change step S32 ′ to “open valve”. Change, change step S36 to "measurement of valve closing time Tc",
The "valve opening time To" in steps S38 and S46 is replaced with the "valve closing time T".
c ”, the“ valve closing time Tc ”may be changed to the“ valve opening time To ”, and the“ valve closing time Tc ”in steps S40, 42, 44, 48 and 50 may be changed to the“ valve opening time To ”. . Such a change corresponds to the invention of claim 5.

<Effects of the Invention> In the steam trap according to the invention described in claim 1, the valve is opened when the degree of supercooling δ becomes larger than the degree of supercooling δ1 at the time of opening, and becomes smaller than the degree of supercooling δ2 at the time of closing. Since the valve is closed at this time, by changing the value of δ1 or δ2, a single steam trap can have the same characteristics as various conventionally known steam traps. For example, when δ1 is increased, the operation cycle (valve opening time + valve closing time) is lengthened, and the characteristic of the thermostatic trap can be obtained, and δ1 is decreased, for example, 5 degrees Celsius.
If the operating period is shortened by selecting from 8 to 8 degrees, the characteristics of the thermodynamic trap can be obtained.
Further, if δ1 is set to be large, it can be used as a radiator trap utilizing the sensible heat of steam.

Therefore, as a manufacturer, only one type of steam trap according to the invention described in claim 1 needs to be manufactured, which facilitates manufacturing. Further, the user does not have to hesitate to select the steam trap, and can change the setting of the supercooling degree signal during opening and closing to obtain the steam trap having desired characteristics.

In the steam trap according to the second aspect of the present invention, the same effect as that of the first aspect of the invention is produced, and the valve closing time is set to a fixed time regardless of the degree of supercooling, so after the valve is closed. The open / close valve can be forcibly opened after a certain period of time has passed, and steam locking can be prevented.

Further, in the steam trap according to the invention described in claim 3, when the valve closing time is made constant as in the invention described in claim 2, the actual valve opening time is measured, and the constant value is set according to the valve opening time. Since the valve closing time as time is changed, even if the load of the steam using device fluctuates, it can be dealt with.

In the steam trap according to the invention described in claim 4, the same effect as in the invention described in claim 1 is produced, and the valve opening time is set to a constant time regardless of the degree of supercooling. The open / close valve can be forcibly closed after a certain period of time has passed, and steam locking can be prevented.

In the steam trap according to the invention described in claim 5, when the valve opening time is constant as in the invention described in claim 4,
Since the actual valve closing time is measured and the valve opening time is changed to a constant time according to this valve closing time, even if there is a fluctuation in the load of the steam using device, this can be accommodated. .

Some conventional thermostatic traps use a bimetal or a bellows as a temperature sensor, but such a temperature sensor is used, so that the response is poor. However, in the steam trap according to the first to fifth aspects of the invention, the steam temperature and the drain temperature are actually measured, the degree of supercooling is obtained based on the measured temperature, and the on-off valve is opened according to the degree of supercooling. Since it is controlled, the responsiveness can be improved. Moreover, the steam trap according to the inventions of claims 1 to 5 can be used as an exhaust air vent for discharging air when air is accumulated in the vapor space.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of a steam trap according to the present invention, FIG. 2 is an operation flowchart of the first embodiment, and FIG. 3 is an operation flowchart of the second embodiment. FIG. 5 is an operation flowchart of the third embodiment, and FIG. 5 is an operation flowchart of the fourth embodiment. 2 ... Steam using device, 6 ... On-off valve, 8 ... Microcomputer (control means), 10 ... Steam temperature measuring device (steam temperature measuring device), 12 ... Discharge temperature measuring device (discharging temperature measuring device) .

Claims (5)

[Claims] 1. An on-off valve which is provided on the discharge side of a steam using device and is opened and closed according to a control signal, and the temperature of steam which is provided on the supply side of the steam using device and is supplied to the steam using device. Steam temperature measuring means, discharge temperature measuring means provided on the supply side of the on-off valve to measure the temperature at the installation position, and a super-cooling degree signal at valve opening indicating the degree of super-cooling when the on-off valve is opened. And a storage means for storing a valve closing supercooling degree signal representing the degree of supercooling when the on-off valve is closed, and based on signals from the steam temperature measuring means and the discharge temperature measuring means. And a means for generating a supercooling degree signal, and an opening control signal for opening the on-off valve when the supercooling degree signal becomes larger than the valve opening supercooling degree signal. Is smaller than the above-mentioned valve closing supercooling degree signal And a control signal generating means for supplying a closing control signal to open and close valve is closed, steam trap comprising. 2. An on-off valve which is provided on the discharge side of the steam using apparatus and which is opened and closed according to a control signal, and the temperature of the steam which is provided on the supply side of the steam using apparatus and is supplied to the steam using apparatus. Steam temperature measuring means, discharge temperature measuring means provided on the supply side of the on-off valve for measuring the temperature at the installation position, and a supercooling degree signal at the time of valve closing showing the degree of supercooling when the on-off valve is closed. A storage means for storing, a means for generating a supercooling degree signal based on signals from the steam temperature measuring means and the discharge temperature measuring means, and a state in which an opening control signal is supplied to the on-off valve. In the above, when the supercooling degree signal becomes smaller than the valve closing supercooling degree signal, a closing control signal generating means for supplying a closing control signal to the on-off valve, and a predetermined time after the closing control signal is generated. After the lapse of time, the above-mentioned opening / closing valve opens. And opening control signal generating means for supplying a control signal, a steam trap comprising. 3. A means for measuring the opening time to which the opening control signal is supplied, a time judging means for judging whether the opening time is within a predetermined range, and the opening time is within the above range. The steam trap according to claim 2, further comprising a changing unit that changes the predetermined time when outside. 4. An on-off valve which is provided on the discharge side of the steam using apparatus and which is opened and closed according to a control signal, and the temperature of the steam which is provided on the supply side of the steam using apparatus and is supplied to the steam using apparatus. Steam temperature measuring means, discharge temperature measuring means provided on the supply side of the on-off valve to measure the temperature at the installation position, and a super-cooling degree signal at valve opening indicating the degree of super-cooling when the on-off valve is opened. Storing means for storing, a means for generating a supercooling degree signal based on signals from the steam temperature measuring means and the discharge temperature measuring means, and a state in which a closing control signal is supplied to the on-off valve. In the above, when the supercooling degree signal becomes larger than the valve opening supercooling degree signal, an opening control signal generating means for supplying an opening control signal to the on-off valve and a predetermined time after the opening control signal is supplied. Later, the on / off valve is controlled to be closed. A closed and control signal generating means, steam trap comprising supplying No.. 5. A means for measuring a closing time during which the closing control signal is supplied, a time judging means for judging whether or not the closing time is within a predetermined range, and the closing time is outside the range. The steam trap according to claim 4, further comprising means for changing the predetermined time.