Patent Application
20210003347
The present invention relates to a condensate drain apparatus, and specifically relates to an orifice-type condensate drain apparatus, which is attached to, for example, a steam transfer pipe such as a steam pipe, or a steam heating device such as a heat exchanger, a dryer and an air conditioner, and discharges and removes steam condensate (steam condensate water) through an orifice after latent heat release.
The orifice-type condensate drain apparatus is conventionally known in which an orifice set to discharge the condensate (hereinafter also referred to as drain) at a specified pressure is incorporated, from advantages that there is no need for a movable member such as an operating valve, durability is very high and no steam leakage occurs due to deterioration of a valve portion. In such an orifice-type condensate drain apparatus, it is necessary to set an orifice hole diameter smaller (for example, 0.5 mmϕ) than a valve-type condensate drain apparatus depending on a planned discharge flow rate of drain, and clogging by foreign matter is likely to occur in an orifice hole. On the other hand, in order to prevent the clogging by foreign matter, the orifice hole diameter needs to be set large (at least 1 mmϕ or more), but live steam containing latent heat tends to leak. Therefore, it was necessary to produce many types of orifices depending on a drain discharge rate.
Therefore, the condensate drain apparatus has been proposed in which a plurality of orifices is arranged in series and in multiple stages and depressurized stepwise to prevent the steam leakage and the clogging of the orifice hole (for example, see Patent Literatures 1 to 3).
Patent Literature 1 discloses the condensate drain apparatus in which the plurality of orifices is arranged in series in a valve chamber and central axes of the plurality of orifices are eccentric in an arrangement direction.
Patent Literature 2 discloses the condensate drain apparatus in which the central axes of the plurality of orifices arranged in series in the valve chamber are eccentric in the arrangement direction, and a plate-like or strip-like temperature responsive element is disposed opposite to each orifice.
Patent Literature 3 discloses the condensate drain apparatus in which the central axes of the plurality of orifices arranged in series in the valve chamber are eccentric in the arrangement direction, and a rolling member rollable by fluid passing through the orifice is disposed in each orifice through the orifice.
An amount of drain passing through the orifice (orifice discharge capability) is generally determined by a differential pressure and the orifice hole diameter, but for example, there is a problem that the related art described in Patent Literature 1 cannot flexibly respond to an increase and decrease in discharge flow rate of the drain.
For example, when applied to the steam heating device (system) having a large variation in drain discharge rate, a multi-stage orifice of the same diameter cannot follow variation of the drain, for example, from the time of startup to the time of steady state, and when the amount of drain is less than about half of the orifice discharge capability, there is a problem that the orifice hole cannot be completely sealed and steam leakage occurs. On the other hand, in order to prevent steam leakage and ensure stable drain discharge capability in steady state, it is necessary to reduce the drain discharge capability at the time of startup, which causes a problem that it takes time for startup.
Further, the related art described in Patent Literatures 2 and 3 impairs the advantage of the orifice-type condensate drain apparatus that the movable member is not required at all, and there is a problem that durability and maintainability are reduced in addition to the problems described above.
That is, in the related art disclosed in Patent Literatures 1 to 3, there is a problem that since a variation range of the drain discharge rate which can be applied (dealt with) by the orifice hole of the same diameter is small (usually up to 50% of the maximum discharge rate), the orifice discharge capability cannot sufficiently follow the increase and decrease in the drain from the time of startup to the time of steady state, and eventually the orifice hole diameter is changed depending on the drain discharge rate or it takes time for startup to the steady state.
Therefore, the present invention has been made in view of the problems of the related art as described above, and an object of the present invention is to provide inexpensively by a simple method the condensate drain apparatus highly adaptable to the increase and decrease in the drain discharge rate while preventing the clogging of the orifice hole.
In order to achieve the above object, a condensate drain apparatus according to the present invention is the condensate drain apparatus in which orifice units each having an orifice and a decompression chamber provided downstream of the orifice are arranged in series and in multiple stages. Each orifice unit includes an orifice plate having an orifice hole of a diameter of 1 mm or more and formed in a thin plate shape, and a decompression plate having a thickness equivalent to that of the orifice plate and having the decompression chamber formed therein. The orifice holes adjacent in an axial direction are formed and arranged shifted in a radial direction from each other.
In such a configuration, it is possible to discharge and remove condensate stably over time from the time of startup to the time of steady state while preventing the clogging of the orifice holes.
Further, each of the orifice holes is formed to have the same diameter, each of the decompression chambers is formed to have the same volume, and the orifice holes of first and final stage orifice units are arranged at a center, while the orifice holes of intermediate orifice units are arranged eccentrically, and adjacent intermediate orifice holes are arranged to have arrangement phases shifted by 180° from each other.
In such a configuration, an apparent flow channel length can be secured to a maximum, and an axial direction can be shortened with multiple stages.
Each of the orifice holes is formed to have the same diameter, each of the decompression chambers is formed to have the same volume, and formation positions of the orifice holes adjacent in an axial direction are arranged alternately and repeatedly in a manner of center, eccentric, center ---.
In such a configuration, it is not necessary to adjust a phase shift of the orifice hole, and a constant flow channel length can be secured to contribute to stabilization of drain discharge capability.
The most downstream orifice hole may be formed and disposed in the center.
In such a configuration, it is possible to prevent erosion on downstream piping and the like in advance.
The most upstream orifice hole may be formed and disposed in the center or eccentrically below the center.
In such a configuration, the orifice hole can be reliably sealed by the drain to stably prevent steam leakage.
In the above, a ratio of a volume of the decompression chamber to an opening volume of the orifice hole may be set to 30 to 200.
In such a configuration, axial shortening can be further achieved to contribute to downsizing of the apparatus and improvement in piping workability.
The orifice plate and the decompression plate may be formed of stainless steel having a thickness of 1 to 2 mm, and may be connected by axial pressure.
In such a configuration, it is possible to significantly improve workability at the time of assembly and maintenance, and to easily respond to the increase and decrease of the orifice units on site.
According to the present invention, while an orifice having a large opening diameter can be adopted, and the clogging of the orifice hole can be prevented in advance, the condensate can be stably discharged and removed from the time of startup to the time of steady state.
Hereinafter, an embodiment of a condensate drain apparatus according to the present invention will be described with reference to the drawings.
The condensate drain apparatus according to the present embodiment is an apparatus, which is used in various steam heating devices such as a heat exchanger, a dryer, and an air conditioner, using steam as a heat source, to minimize steam leakage and to remove condensate from the device. The condensate drain apparatus is attached to a stage subsequent to (downstream of) the steam heating device (not shown), and an orifice is provided in the middle of a condensate channel formed inside the condensate drain apparatus. Then, drain, that is, the condensate is discharged out of the device through the orifice by a differential pressure.
Specifically, as schematically shown in
Each orifice units 10U1-N includes a plate-like (a disc-shaped in this example) orifice plate 12P1-N having orifice holes of the same diameter, and a hollow disk-shaped decompression plate 14P1-N having an outer diameter equivalent to that of the orifice plate 12P1-N and forming a decompression space (decompression chamber) 14S1-N at a stage subsequent to the orifice plate 12P1-N. In the present embodiment, the orifice units 10U1-N are arranged in series and in multiple stages (multistage) along a condensate discharge channel formed in the housing HG.
As schematically shown in
Each decompression plate 14P1-N has an outer diameter equivalent to that of the orifice plate 12P1-N, and is formed of a ring-shaped seal washer (ring washer), to set up a decompression space (decompression chamber) 14S1-N having the same volume with the same opening diameter (14.00 mmϕ in this example).
In the present embodiment, both of the orifice plate 12P1-N and the decompression plate 14P1-N are thin stainless steel plates, and are formed to the equivalent thickness (1 mm in this example). Thus, since the orifice plate 12P1-N and the decompression plate 14P1-N are formed of separate plate-like members of the same material and the same thin thickness, the orifice plate 12P1-N and the decompression plate 14P1-N can be integrally displaced (deformed) in the same direction even when an unexpected load is applied in an axial direction. Thus, it is possible to maintain sealing properties stably over the years with respect to changes in discharge flow rate of the drain from the time of startup to the time of steady state without separately providing a sealing member such as a gasket, as compared to a conventional structure in which the decompression space and the orifice hole are integrally formed.
The thicknesses of the orifice plate 12P1-N and the decompression plate 14P1-N are preferably 1 to 2 mm. Because, if they are 1 mm or less, their strength is insufficient, and if they are 2 mm or more, followability (adaptability) to the changes in discharge flow rate of the drain, and piping workability along with increase in axial length are reduced.
Further, in the present embodiment, a final stage orifice unit 10UN is axially pressed and supported by a spring washer SW via a hollow cylindrical collar 15.
In this manner, with a simple structure in which each orifice unit 10U1-N is formed by the orifice plate 12P1-N and the decompression plate 14P1-N having the same diameter and the same thickness, and is pressed (pressurized) and supported in the axial direction by the spring washer SW, it is possible to significantly improve workability at the time of assembly and maintenance. In addition, it is also possible to easily respond to an increase and decrease of the orifice units 10U1-N and replacement to different orifice diameters on site. Note that reference numeral 17 denotes a bushing for supporting the spring washer SW.
Further, in the present embodiment, the orifice holes 11h1-Nof the adjacent orifice units 10U1-N are formed and arranged shifted (eccentrically) in a radial direction from each other so as not to be arranged on the same straight line in a condensate flow channel direction (hereinafter, axial direction).
Specifically, the central orifice plate 12Pc is disposed in a first stage (most upstream) orifice unit 10U1. Although the eccentric orifice plate 12Pd may be disposed, it is preferable to adjust an arrangement phase so that the eccentric orifice hole 11hd is positioned below the center in this case. Thus, the orifice holes 11h can be more reliably sealed by introduced drain DR, to prevent the steam leakage in advance.
Further, the central orifice plate 12Pc is disposed on a most downstream (discharge side) orifice unit 10UN. Thus, the drain DR can be discharged from the center, to suppress erosion on downstream piping and the like.
On the other hand, the eccentric orifice plates 12Pd are arranged in the middle orifice units 10U2-(N-1), and the adjacent eccentric orifice plates 12Pd are adjusted and arranged so that positions of the eccentric orifice holes 11hd are shifted by 180° from each other. Thus, a flow channel length can be secured to the maximum (an apparent flow channel length can be increased). Note that a phase difference between the eccentric orifice holes 11hd of the adjacent eccentric orifice plates 12Pd is preferably at least ±90° or more.
In this manner, the orifice holes 11h1-N adjacent in the axial direction are formed and arranged shifted (eccentrically) in the radial direction from each other to form a complicated flow channel, and so-called labyrinth effect can be enhanced in which pressure loss of fluid to be leaked out is increased, and an amount of leakage is reduced to improve the sealing properties. In addition, since the apparent flow channel length can be increased, the axial length of multi-stage orifice units 10U1-N can be shortened to improve workability of connection to piping and the like.
Further, by setting the thickness of the decompression plates 14P1-N thin within a predetermined range (shortening a depth of the decompression chambers 14S1-N), it is possible to prevent generation of turbulent flow (vortex flow, spiral flow) in the decompression space due to single layer fluid SF at the time of startup to accelerate rapid discharge of the drain DR, and to reduce length in a depth direction to contribute to improve the piping workability and downsizing of the apparatus.
In the condensate drain apparatus according to the present embodiment configured as described above, in the steady state in which the condensate introduced from a steam heating device SH reaches a saturation temperature, as schematically shown in
On the other hand, in the startup state in which the condensate introduced from the steam heating device SH is less than the saturation temperature, as schematically shown in
Next, comparative verification was conducted to define an appropriate relationship between the orifice hole and the decompression chamber using the condensate drain apparatus 1 according to the present embodiment and the condensate drain apparatus of the conventional structure. Verification results will be described below as Examples and Comparative Examples (the conventional structure).
Here, as the condensate drain apparatus of the conventional structure, a condensate drain apparatus 100 of the conventional structure (orifice units 100U1-4 integrally formed with the central orifice hole and the decompression chamber, each unit having an axial length of 12 mm) as schematically shown in
When it was set such that the diameter of the orifice hole 11h: 1.0 mmϕ, the thickness of the orifice plate 12P: 1.0 mm, the opening diameter of the decompression plate 14P: 14.0 mmϕ, the thickness of decompression plate 14P: 1.0 mm, and the number of orifice stages N: 16 stages (axial length: 32 mm), a drain discharge rate equivalent to that of the condensate drain apparatus of the conventional structure of 0.5 mmϕ×4 stages (axial length: 48 mm) was obtained at the time of steady state. Then, in the condensate drain apparatus according to the present embodiment, it was confirmed that it was possible to discharge the drain DR stably and smoothly without causing the steam leakage upon an increase and decrease in the drain DR from the startup state to the steady state (also smoothly respond to a sudden increase in the drain particularly at the time of startup and the like). On the other hand, in the condensate drain apparatus of the conventional structure, clogging due to usage over time and an increase in startup time were observed (Comparative Example 1-1).
That is, in the condensate drain apparatus according to the present embodiment, even when the axial length was reduced to about 66% as compared to the conventional structure while the hole diameter was enlarged by four times in an orifice opening area to prevent the clogging, the stable drain discharge capability was obtained from the time of startup to the time of steady state.
A ratio R of a decompression space volume to an orifice opening volume at this time was R=π/4×142×1:π/4×1.02×1=196.
When it was set such that the diameter of the orifice hole 11h: 1.5 mmϕ, the thickness of the orifice plate 12P: 1.0 mm, the opening diameter of the decompression plate 14P: 14.0 mmϕ, the thickness of the decompression plate 14P: 1.0 mm, and the number of orifice stages N: 20 stages (axial length: 40 mm), the drain discharge rate equivalent to that of the condensate drain apparatus of the conventional structure of 0.7 mmϕ×4 stages (axial length: 48 mm) was obtained at the time of steady state. Then, in the condensate drain apparatus according to the present embodiment, it was confirmed that it was possible to discharge the drain DR stably and smoothly without causing the steam leakage upon the increase and decrease in the drain DR from the startup state to the steady state (also smoothly respond to the sudden increase in the drain particularly at the time of startup and the like). On the other hand, in the condensate drain apparatus of the conventional structure, the clogging due to the usage over time and the increase in startup time were observed (Comparative Example 1-2).
That is, in the condensate drain apparatus according to the present embodiment, even when the axial length was reduced to about 83% as compared to the conventional structure while the hole diameter was enlarged by 4.6 times in an orifice opening area to prevent the clogging, the stable drain discharge capability was obtained from the time of startup to the time of steady state.
The ratio R of the decompression space volume to the orifice opening volume at this time was R=π/4×142×1:π/4×1.52×1≈87.
When it was set such that the diameter of the orifice hole 11h: 1.5 mmϕ, the thickness of the orifice plate 12P: 1.0 mm, the opening diameter of the decompression plate 14P: 14.0 mmϕ, the thickness of the decompression plate 14P: 1.0 mm, and the number of orifice stages N: 16 stages (axial length: 32 min), the drain discharge rate equivalent to that of the condensate drain apparatus of the conventional structure of 0.8 mmϕ×4 stages (axial length: 48 mm) was obtained at the time of steady state. Then, in the condensate drain apparatus according to the present embodiment, it was confirmed that it was possible to discharge the drain DR stably and smoothly without causing the steam leakage upon the increase and decrease in the drain DR from the startup state to the steady state (also smoothly respond to the sudden increase in the drain particularly at the time of startup and the like). On the other hand, in the condensate drain apparatus of the conventional structure, the clogging due to the usage over time and the increase in startup time were observed (Comparative Example 1-3).
That is, in the condensate drain apparatus according to the present embodiment, even when the axial length was reduced to about 66% as compared to the conventional structure while the hole diameter was enlarged by about 3.5 times in an orifice opening area to prevent the clogging, the stable drain discharge capability was obtained from the time of startup to the time of steady state.
The ratio R of the decompression space volume to the orifice opening volume at this time was R≈87.
When it was set such that the diameter of the orifice hole 11h: 3.0 mmϕ, the thickness of the orifice plate 12P: 1.0 mm, the opening diameter of the decompression plate 14P: 14.0 mmϕ, the thickness of the decompression plate 14P: 1.0 mm, and the number of orifice stages N: 20 stages (40 mm) (Comparative Example 1-4), the steam leakage was observed (R=π/4×142×1:π/4×3.02×1≈22). Note that when the diameter of the orifice hole 11h was set to 2.5 mmϕ (Example 1-4), no steam leakage was observed (R=π/4×142×1:π/4×2.52×1≈31).
The verification results described above are summarized and shown in Table 1.
From the above, it was confirmed that the condensate drain apparatus can be obtained in which by setting the ratio R of the decompression space volume to the orifice opening volume to 30 to 200, the orifice opening area is enlarged by three times or more than the conventional one (the orifice diameter is preferably 1.0 to 2.5 mm, more preferably 1.0 to 1.5 mm) to prevent the clogging, while it is possible to shorten the axial length (downsizing) compared to the conventional one while significantly increasing the number of stages (16 to 20 stages), to improve the piping workability, to widely respond to variation of the drain from the time of the startup to the time of the steady state, and to discharge the drain stably.
Next, another embodiment will be described with reference to
As schematically shown in
Specifically, the central orifice plate 12Pc is disposed in the first stage (most upstream) orifice unit 10U1, and subsequently, the eccentric orifice plate 12Pd and the central orifice plate 12Pc are arranged alternately and repeatedly. As in the previous embodiment, the central orifice plate 12Pc is disposed in the final stage (most downstream) orifice unit 10UN. That is, in the condensate drain apparatus 1A according to the present embodiment, the central orifice plate 12Pc (central orifice hole 11hc) is interposed between the adjacent eccentric orifice plates 12Pd (eccentric orifice holes 11hd).
By forming and arranging the orifice holes 11h in this manner, it is possible to always secure the constant flow channel length while making a complicated phase adjustment work unnecessary when arranging the orifice holes 11h as compared with the previous embodiment, thereby realizing significant improvement in assembling workability, and securing more stable drain discharge capability over time.
In addition, as a result of comparing the condensate drain apparatus 1A according to the present embodiment thus configured with the condensate drain apparatus of the conventional structure, it was confirmed that substantially the same performance as that of the previous embodiment can be obtained more stably.
As described above, according to the condensate drain apparatus according to the present invention, by making a predetermined multi-stage structure, it is possible to enlarge the orifice hole diameter to prevents the clogging, and to stably discharge and remove the condensate against variations in an amount of drain from the time of startup when the condensate is in an unsaturated state to the time of steady state when the condensate reaches a saturated state.
Further, by setting a ratio of the decompression chamber volume to the orifice opening volume within a predetermined range, it is possible to shorten the axial direction with multiple stages, thereby improving the piping workability while extending a range responding to the variation of the drain.
The technical scope of the present invention is not limited to the above-described embodiments, but various changes or modifications can be made without departing from the gist of the present invention. For example, a separate bypass valve (control valve) may be provided for emergency response or the like.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-060164 | Mar 2018 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2019/011288 | 3/18/2019 | WO | 00 |
