Steam Locking Elimination System

Abstract

To provide a steam locking cancellation system that can reliably cancel steam locking without causing steam loss while having a simple structure.SOLUTION: Steam is supplied to the inside of a cylinder body 4 through a steam supply pipe 12 to heat an object in contact with an outer peripheral surface of the cylinder body 4. The steam is condensed by heating the object, and drainage 30 is accumulated in an internal space of the cylinder body 4. The drainage 30 is discharged through a drainage pipe 16. When steam locking occurs, the drainage is not properly discharged from a steam trap 2, and the temperature of the drainage pipe 16 on the downstream side of the steam trap 2 is decreased. A controller 25 grasps the temperature decrease through a temperature sensor 41, opens a cooling valve 45 to pass industrial water, and cools the drainage pipe 16 on the upstream side of the steam trap 2 by a coil part 20a. The steam in the drainage pipe 16 is condensed to cancel the steam locking.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The steam locking elimination system of the present application relates to a technique for eliminating steam locking, which occurs when only steam is present in a part of a steam trap or the like, blocking the flow of condensate and making it impossible to properly discharge the condensate. [Background technology]

[0002] Industrial plants and the like often have piping systems installed to transport steam generated in boilers, and the steam is sent through these piping systems to various equipment and used as a heat source, etc. The steam condenses due to heat release during transportation and heat exchange in each equipment, generating drain (condensed water) in the piping system.

[0003] A steam trap is installed in the piping system to discharge this condensate outside the system. Steam traps come in a variety of structures, but float traps have a hollow float built into the valve chest. Under normal circumstances, this float blocks the condensate discharge port formed near the bottom of the valve chest. However, when condensate flows into the valve chest and the condensate level rises, the float rises accordingly, automatically opening the condensate discharge port and opening the valve.

[0004] When the condensate discharge port is opened, condensate is allowed to pass through the valve chamber, and the condensate remaining in the valve chamber is automatically discharged from the condensate discharge port due to the force of the high pressure in the piping. After the condensate is discharged, the float descends and returns to its seat, blocking the condensate discharge port again. The float repeatedly rises and falls in this manner to discharge the condensate, but because the condensate discharge port is always submerged in condensate, steam does not leak from the steam trap under normal conditions.

[0005] However, in a steam trap, depending on the conditions of the inflowing steam and condensate, steam may get trapped in part of the drain in the valve chest or piping, blocking the flow of condensate and causing steam locking, which prevents the condensate from being discharged properly.

[0006] A system for eliminating such steam locking is disclosed in Patent Document 1, which will be described later. The heating cylinder 100 disclosed in Patent Document 1 includes a cylinder body 10 into which steam is supplied, and a drain pipe 20 that discharges drainage due to the pressure inside the cylinder body 10. A drain pipe 31 is connected downstream of the drain pipe 20, and this drain pipe 31 is provided with a steam trap 40 for automatically discharging drainage.

[0007] A bypass pipe 32 is connected to the drain pipes 31 on the upstream and downstream sides of the steam trap 40, and a valve 50 is attached to this bypass pipe 32. The valve 50 opens and closes based on a signal from a control unit 60, and the control unit 60 controls the opening and closing of the valve 50 according to the amount of drain stored in the cylinder body 10.

[0008] That is, when steam locking occurs in the steam trap 40, the condensate is not properly discharged, and the amount of condensate accumulated in the cylinder body 10 increases. The control unit 60 detects this increase in the amount of condensate accumulated and opens the valve 50. As a result, the condensate bypasses the steam trap 40 and is discharged through the bypass pipe 32, eliminating the steam locking. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-86248 Summary of the Invention [Problem to be solved by the invention]

[0010] In the technology disclosed in the aforementioned Patent Document 1, a bypass pipe 32 is installed to eliminate steam locking. This bypass pipe 32 needs to be branched off from the drain pipe 31, which increases the equipment cost.

[0011] Furthermore, since the valve 50 of the bypass pipe 32 is opened to eliminate steam locking, if steam leaks from the cylinder body 10 through the drain pipe 20 immediately after the drain is discharged, there is a risk of steam loss.

[0012] Therefore, the steam locking elimination system according to the present invention aims to provide a steam locking elimination system that can reliably eliminate steam locking without causing steam loss despite having a simple configuration. [Means for solving the problem]

[0013] The steam locking elimination system according to the present application comprises: A flow path through which condensed water generated from steam flows from upstream to downstream. a discharge valve provided in the flow passage for discharging the condensed water downstream; a cooling means for cooling the flow passage upstream of the discharge valve or the discharge valve; The present invention is characterized by the following. [Effects of the Invention]

[0014] In the steam locking elimination system according to the present application, the cooling means cools the discharge valve or the flow passage upstream of the discharge valve. Therefore, even if steam locking of the discharge valve causes steam to be trapped and condensed water is not properly discharged from the discharge valve, the cooling means can condense the steam trapped in the flow passage upstream of the discharge valve or in the discharge valve and liquefy it into condensed water. Therefore, despite the simple configuration, steam locking can be reliably eliminated without causing steam loss. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a block diagram of the overall configuration of a steam-using device relating to a heating cylinder 1, illustrating a first embodiment of a steam-locking elimination system according to the present application. [Figure 2] 2 is a graph showing a change over time in the temperature detected by the temperature sensor 41 shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] [Terminology used in the embodiments] The main terms used in the embodiments correspond to the following elements of the steam locking prevention system according to the present application:

[0017] Steam trap 2...discharge valve Drain pipe 16...flow passage Cooling piping 20...Cooling means, cooling path Temperature sensor 41: Temperature detection means Cooling valve 45: Cooling path on / off valve Drain...Condensed water Industrial water...Cooling fluid

[0018] [First embodiment] A first embodiment of a steam-locking elimination system according to the present application will be described with reference to Figures 1 and 2. In this embodiment, an example is given in which the steam-locking elimination system according to the present application is applied to a steam-using device related to a heating cylinder 1.

[0019] (Explanation of the overall configuration of the steam-using device related to the heating cylinder 1) First, the overall configuration of the steam-using device related to the heating cylinder 1 will be described with reference to Figure 1. The heating cylinder 1 has a cylinder body 4, which is configured as a hollow column extending along a central axis L1. Shafts 4a and 4b extending in the direction of the central axis L1 are provided on both ends of the cylinder body 4, and the shafts 4a and 4b are rotatably supported by bearings (not shown).

[0020] A steam supply pipe 12 is connected to the shaft portion 4a of the cylinder body 4, and steam is supplied to the inside of the cylinder body 4 through this steam supply pipe 12. In other words, the heating cylinder 1 is a heater that uses steam as a heat source, and can heat objects such as paper or laundry that come into contact with the outer circumferential surface of the cylinder body 4. Heating the object causes the steam to release heat, and this heat release causes the steam inside the cylinder body 4 to condense and liquefy into a drain 30, which stays and accumulates in the internal space of the cylinder body 4.

[0021] A drain pipe 14 is disposed in the internal space of the cylinder body 4. One end of this drain pipe 14 is located near the bottom of the internal space of the cylinder body 4, and the other end passes through the shaft portion 4a and is located outside the cylinder body 4. The drain pipe 14 is a siphon tube that receives steam pressure from the cylinder body 4 and discharges drain 30 to the outside of the cylinder body 4. In terms of the flow of drain, the inside side of the drain pipe 14 inside the cylinder body 4 is the upstream side, and the outside side of the cylinder body 4 is the downstream side.

[0022] A drain piping 16 is connected to the downstream side of the drain pipe 14. A steam trap 2 is provided on this drain piping 16. The steam trap 2 is an automatic valve that discharges drain outside the piping as needed and operates to minimize steam leakage.

[0023] Steam traps come in a variety of structures, but the steam trap 2 in this embodiment is a float trap. A float trap has a hollow float built into the valve chest (not shown). Under normal conditions, this float blocks a condensate discharge port formed near the bottom of the valve chest (valve closed), blocking the passage of condensate through the valve chest. However, when condensate flows into the valve chest and the condensate level rises, the float rises accordingly, automatically opening the condensate discharge port and opening the valve.

[0024] By opening the condensate discharge port, condensate is allowed to pass through the valve chamber, and the condensate accumulated in the valve chamber is automatically discharged from the condensate discharge port due to the force of the high pressure in the piping. After the condensate is discharged, the float descends and returns to its seat, again blocking the condensate discharge port. Note that although the float repeatedly rises and falls in this way to discharge the condensate, the condensate discharge port remains submerged in the condensate at all times, so no steam leaks from the steam trap. In this embodiment, the condensate discharged from the steam trap 2 flows into the condensate recovery pipe 18.

[0025] A water supply pipe 10 for transporting industrial water is arranged in the installation area of ​​the heating cylinder 1. A cooling pipe 20 is provided as a bypass pipe in the water supply pipe 10. That is, both ends of the cooling pipe 20 are connected to the upstream part of the water supply pipe 10 and the downstream part of the water supply pipe 10, respectively, and the industrial water can circulate through the cooling pipe 20.

[0026] The cooling pipe 20 has a coil portion 20a, which is arranged so as to be wound around the drain pipe 16 upstream of the steam trap 2. The winding diameter of the coil portion 20a is formed to be slightly larger than the outer diameter of the drain pipe 16, and the coil portion 20a is wound around the drain pipe 16 in close proximity. By having the coil portion 20a wind around the drain pipe 16, efficient cooling can be achieved.

[0027] A cooling valve 45 is provided in the cooling pipe 20. This cooling valve 45 is, for example, an electromagnetic valve, and can open and close the valve in accordance with a valve open signal or a valve close signal from the controller 25. Note that, under normal circumstances, the cooling valve 45 is closed. A temperature sensor 41 is provided in the drain pipe 16 downstream of the steam trap 2, and the temperature of the drain pipe 16 detected by the temperature sensor 41 is output to the controller 25 as a detection signal.

[0028] (Explanation of how to resolve steam locking) In a steam trap, depending on the conditions of the inflowing steam and condensate, re-evaporated steam may become trapped in the valve chest or part of the discharge pipe of the steam trap. In this case, even though condensate is generated upstream, the water level in the valve chest does not rise, so the float cannot rise and the valve remains closed, preventing proper condensate discharge. This is known as steam locking, and the operation to resolve this steam locking phenomenon is described below.

[0029] Because drain is liquefied condensate of high-temperature, high-pressure steam, the temperature of the drain discharged from the steam trap 2 is usually high. For this reason, the temperature of the drain piping 16 is maintained at a high temperature unless steam locking occurs. However, if steam locking occurs and the steam trap 2 is no longer able to properly discharge drain, the temperature of the drain piping 16 downstream of the steam trap 2 will decrease over time.

[0030] 2 is a graph showing, by curve x, the change over time in the temperature detected by temperature sensor 41 provided in drain pipe 16 downstream of steam trap 2. As curve x shows, when steam locking occurs, the detected temperature drops, and eventually curve x falls below low temperature threshold value T1 at time point P1. This low temperature threshold value T1 is a value stored in advance in controller 25 and is the threshold value of temperature drop at which it can be determined that steam locking has occurred.

[0031] At time P1 when the detected temperature reaches the low temperature threshold T1, the controller 25 sends a valve open signal to the cooling valve 45. This causes the cooling valve 45 to open, industrial water flows through the cooling pipe 20, and the coil portion 20a exchanges heat with the drain pipe 16 upstream of the steam trap 2. Because the industrial water is at a relatively low temperature, the drain pipe 16 is cooled by the heat exchange.

[0032] This cooling of the drain pipe 16 causes the steam in the drain pipe 16 or steam trap 2 that was causing the steam locking to release heat, condense, and liquefy into drain. As the intervening steam turns into drain, the steam locking is resolved, high-temperature drain flows normally in the drain pipe 16, and the discharge of high-temperature drain from the steam trap 2 resumes.

[0033] As a result, the temperature of the drain pipe 16 downstream of the steam trap 2 rises and exceeds the high temperature threshold value T2 at time P2, as shown by curve x in Figure 2. This high temperature threshold value T2 is a value stored in advance in the controller 25, and is the threshold value of the temperature rise at which it can be determined that steam locking has been resolved.

[0034] At time P2 when the detected temperature reaches the high temperature threshold T2, the controller 25 sends a valve closing signal to the cooling valve 45. This causes the cooling valve 45 to close, cutting off the flow of industrial water in the cooling pipe 20. Accordingly, cooling of the drain pipe 16 by the coil portion 20a also stops.

[0035] As described above, even if steam locking causes steam to be trapped and prevent condensate from being properly discharged from the steam trap 2, cooling by the coil portion 20a of the cooling pipe 20 condenses the steam trapped in the drain pipe 16 upstream of the steam trap 2 and in the steam trap 2, and liquefies it into condensate. Therefore, even with a simple configuration, steam locking can be reliably eliminated without causing steam loss.

[0036] [Other embodiments] In the above-described embodiment, a float-type steam trap 2 is used as an example of a discharge valve, but this is not limited to this, and a valve with another configuration may be used as long as it can discharge condensed water (drainage).

[0037] In the above-described embodiment, the cooling pipe 20 having the coil portion 20a that surrounds the drain pipe 16 is exemplified as the cooling means and cooling path. However, the present invention is not limited to this, and other shapes and structures can be used as long as they cool the flow path (such as the drain pipe 16). For example, although the example in which the coil portion 20a of the cooling pipe 20 surrounds the drain pipe 16 while being close to the drain pipe 16 has been shown, the coil portion 20a (cooling path) may also be configured to surround the drain pipe 16 while being in contact with the drain pipe 16 (flow path). Furthermore, a straight pipe portion, rather than a coiled one, may be disposed close to or in contact with the flow path (such as the drain pipe 16) to cool the flow path (such as the drain pipe 16).

[0038] Furthermore, as the cooling means and cooling path, a water-cooled cooling pipe 20 using the flow of industrial water has been exemplified, but the flow path (drain pipe 16, etc.) can also be cooled by a forced air cooling method in which a flow of external air is brought into contact with the cooling pipe using a fan or the like.

[0039] Furthermore, in the above-described embodiment, an example has been shown in which the drain pipe 16 (flow passage) upstream of the steam trap 2 (discharge valve) is cooled, but the discharge valve (steam trap 2, etc.) may also be cooled by arranging a cooling means (cooling pipe 20, etc.) in close proximity to or in contact with the discharge valve (steam trap 2, etc.).

[0040] In addition, in the above-described embodiment, the cooling valve 45, which is an electromagnetic valve, is exemplified as the cooling path opening / closing valve, and the temperature sensor 41 is exemplified as the temperature detection means, but these are not limited to these, and other configurations may be adopted for each.

[0041] Furthermore, in the above-described embodiment, an example has been shown in which, when steam locking occurs, a drop in the temperature of the drain pipe 16 is detected and the cooling valve 45 is opened to cool the drain pipe 16. However, the occurrence of steam locking may also be prevented by constantly flowing a cooling fluid (industrial water, etc.) through the cooling means and cooling path (cooling pipe 20, etc.).

[0042] Furthermore, the steam locking elimination system according to the present application may be configured by combining the above-described embodiments. [Explanation of symbols]

[0043] 2: Steam trap 16: Drain pipe 20: Cooling pipe 41: Temperature sensor 45: Cooling valve

Claims

1. A flow path through which condensed water generated from steam flows from upstream to downstream. a discharge valve provided in the flow passage for discharging the condensed water downstream; a cooling path for cooling the flow passage upstream of the discharge valve or the discharge valve, the cooling path having a cooling fluid flowing therethrough, the cooling path being disposed in contact with or in proximity to the flow passage upstream of the discharge valve or the discharge valve, and performing heat exchange with the flow passage upstream of the discharge valve or the discharge valve; a cooling path on-off valve provided in the cooling path and performing an opening and closing operation to block or open the flow of the cooling fluid; a temperature detection means for detecting the temperature of the flow passage downstream of the discharge valve; It is equipped with The cooling path opening / closing valve performs the opening / closing operation based on the temperature detected by the temperature detection means. A steam locking elimination system characterized by the above.

2. 2. The steam locking elimination system according to claim 1, The cooling path has a coil portion that is wound around the flow passage upstream of the discharge valve in contact with or in close proximity to the flow passage. A steam locking elimination system characterized by the above.

3. In the steam locking elimination system according to claim 1 or claim 2, The discharge valve is a steam trap. A steam locking elimination system characterized by the above.

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