CONDENSATE DRAINAGE APPARATUS

Abstract: An apparatus for draining condensate from a vapor equipment is provided which comprises a cylindrical casing connected in fluid communication with the vapor equipment and defining a flow path for conveying vapor and condensate, an orifice disk disposed in the casing transverse to the flow path and having a plurality of orifices formed therein, and at least one partition disposed in the casing upstream or downstream of the orifice disk with a predetermined spacing therefrom, the partition covering a predetermined portion of the flow path. The structure is applicable to a variety of valves including sluice and ball valves.

Description: Field of the Invention This invention relates to an apparatus for draining condensate from a vapor equipment including steam conveying conduits, steam distribution lines, heat exchangers, dryers and air conditioners wherein part of steam condenses into drain. Discussion of the Prior Art A typical condensate draining apparatus includes a cylindrical casing and an orifice formed therein. The draining apparatus is connected to a steam equipment whereby drain is conveyed to the outside of the equipment through the orifice under the pressure of steam. It is desired for this type of drainage apparatus that any drain is fully removed, leakage of steam is prevented, and foreign matters including rust, scale, dust, and metal debris which is left during attachement of the apparatus or connection of conduits do not clog the orifice. It is difficult to construct a drainage apparatus capable of meeting all these requirements. Previous apparatus has orifices arranged in plural stages in a flow path wherein the pressure difference between inlet and outlet ports of the path is sheared by these orifices. This design has the advantage that leakage of steam is minimized even when the orifices have an increased diameter. The apparatus, however, does not perform well when a great amount of drain is to be disposed of. US-A-2783770 and FR-A-1032360 show constructions with features of the first part of claim 1 hereto. According to this invention there is provided apparatus for use in draining condensate from equipment which, in use, contains a vapour, comprising a casing to be connected in fluid communication with the equipment and defining a flow path for vapour and condensate, means defining at least one orifice for restricting the flow path, and a partition disposed in said casing at a predetermined spacing from said means defining an orifice and extending downwardly into the flow path to close a predetermined portion of the flow path, characterised in that said flow path is generally rectilinear and in that said means comprises a plate member disposed in said casing transverse to the flow path and having at least one orifice formed therein. The present invention can provide a condensate drainage apparatus which can discharge any amount of drain varying from zero to a substantial amount, prevents an orifice from being clogged with foreign matters, and allows little leakage of steam. Such apparatus may also be such as to discharge drain independent of whether the amount of drain is large or small, and allows little leakage of steam. In some preferred forms, there is a plurality of partitions disposed in said casing wherein when the casing is oriented so that a first partition closes an upper portion of the flow path, a second partition, upstream of said first partition closes an upper portion of the flowpath, a second partition, upstream of said first partition has a lower edge lower than a lower edge of the first partition. In other preferred forms the casing is a sluice valve casing and the partition comprises a valve element movably mounted in said casing to project downwardly into the flow path and to controllably restrict the flow path. The invention will be better understood from the following description which is given by way of example only with reference to the accompanying drawings in which:- FIGS. 1 through 6 illustrate various embodiments of a condensate drainage apparatus according to a first preferred aspect of the present invention; FIG. 1 being an axial cross section of one embodiment; FIGS. 2 and 3 being radial cross sections taken along lines II-II and III-III in FIG. 1; FIG. 4 being a cross section of the apparatus in operation; FIG. 5 being a cross section of another embodiment; and FIG. 6 is a radial cross section as viewed in the direction of an arrow VI in FIG. 5; FIGS. 7 through 11 illustrate various embodiments of a condensate drainage apparatus according to a second preferred aspect of the present invention; FIG. 7 being an axial cross section of one embodiment in a closed state; FIG. 8 being a radial cross section taken alone lines VIII-VIII in FIG. 7; FIG. 9 being a cross section similar to FIG. 7, but in a half open state; FIG. 10 being a cross section of another embodiment; and FIG. 11 is a cross section of a further embodiment. DESCRIPTION OF THE PREFERRED EMBODIMENTS Condensate drainage apparatus of a first type according to the present invention is described. The apparatus of the above construction is connected to a steam equipment, typically a conduit thereof in a horizontal arrangement. Since drain is present near the bottom of the conduit, the drain passes through an open space left in the flow path below the partition to reach the orifices. The drains is thus discharged out of the apparatus through the orifices. In the embodiment wherein the apparatus is connected in a horizontal position, the partition is located upstream of the orifice disk to interfere an upper space of the flow path of the cylindrical casing, preventing passage of steam. Leakage of steam is thus minimized. As defined above, the orifice disk is formed with a plurality of orifices. Preferably, those orifices located in a lower portion of the disk have a larger diameter than those orifices located in an upper portion of the disk, allowing a great amount of condensate flowing along the bottom of the conduit to be smoothly drained. Foreign matters such as rust and dust and debris which would be sometimes introduced or generated tend to collect near the bottom of the conduit. Location of a larger diameter orifice in a lower portion of the disk is convenient to convey away such foreign matters along with the drain through the orifice. There is a little likelihood that the orifice might be clogged to interrupt drainage. The apparatus is compact since the orifice disk and the partition are disposed within the cylindrical casing. Maintenance and inspection is usually unnecessary and if necessary, may be carried out simply by removing the orifice disk and partition from the casing. The apparatus has a simple structure which is easy to assemble and inexpensive to manufacture, and has little chance of failure. In the practice of the present invention, the components of the apparatus including the cylindrical casing, orifice disk and partition are desirably formed of corrosion resistant steel such as stainless steel. Only for a manufacturing reason, the partition is desirably secured to a cylindrical space by welding. It suffices according to the present invention that the orifice disk and the partitions are disposed within the casing although it is desired that a retainer ring be threadably engaged in the casing to retain the orifice disk and the partition in place. Referring to FIGS. 1 through 6, there is illustrated a condensate drainage apparatus according to the first type. In FIG. 1, a condensate drainage apparatus generally designated at D includes a cylindrical casing 1, an orifice disk 10, a partition 20, and a retainer ring 30. The cylindrical casing 1 defines an axial bore therein for conveying steam and condensate in an arrowed direction. The casing 1 has radial flanges 2 and 2 at opposed ends so that the casing can be directly or indirectly connected to a steam equipment or conduit through the flange. On the downstream side, that is, on the left side in FIG. 1, the inside wall of the cylindrical casing 1 is provided with a step 3 so that the inside wall includes an upstream portion having a larger diameter and a downstream portion having a smaller diameter. The orifice disk 10 is mounted in the larger diameter portion adjacent the step 3. On the upstream side, that is, on the right side in FIG. 1, the inside wall of the cylindrical casing 1 is machined with threads 4. The orifice disk 10 includes collars 11 and 11 having an outer diameter substantially equal to the inner diameter of the larger diameter inside wall portion of the cylindrical casing 1. An O-ring 12 is fitted between the collars 11 and 11. The orifice disk 10 is provided with a plurality of orifices. As seem from FIG. 2, an orifice 13 having a relatively large diameter of, for example, 16 mm is located in a lower portion, preferably at the bottom of the disk. Five orifices 14 have a relatively small diameter of, for example, 8 mm are spaced an equal distance from the center of the orifice 13. The central one of these small orifices 14 is concentric with the orifice disk 10. On each side of the center orifice 14, two orifices 14 are located at an angle of 30°. However, the lowermost one of the orifices in the orifice disk may preferably have the largest diameter. The orifice disk 10 is further formed with orifices 15, 16, 16 in an upper portion. The orifice 15 having a diameter of 6 mm, for example, is located on a vertical centerline 17. The other orifices 16 and 16 having a diamter of 7 mm, for example, are located on lines crossing the centerline 17 at an angle of 45° and spaced an equal distance from the orifice 15. The orifice 13 constitutes a relatively large diameter orifice while the remaining orifices 14, 15 and 16 constitute relatively small diameter orifices. For the above-exemplified diameters of the orifices, the orifice disk 10 has an outer diamter of 80 mm, for example. The partition 20 is vertically mounted in the bore of the cylindrical body 1 and located upstream of the orifice disk 10 with a predetermined spacing from the disk. Two cylindrical spacers 21 and 27 are fitted in the bore of the cylindrical body 10 to hold the partition 20 in place. The partition 20 is fixedly secured to the downstream spacer 21. As seen from FIG. 3, the partition 20 is of a semi-circular shape in a plan view and has a horizontal lower edge 23 which is extended downward beyond the central axis of the cylindrical casing 1. This means that a lower portion of the bore of the cylindrical casing 1 is left open while an upper portion thereof is closed by the partition 20. The retainer ring 30 which is an annular member having a bore for conveying steam and condensate is threaded into the cylindrical casing 1 at the upstream end. The retainer ring 30 has a downstream end 31 which urges the corresponding end of the spacer 27. To this end, the retainer ring 30 is provided on the outer wall with male threads 33 which are in engagement with the female threads 4 inside the cylindrical casing 1. The retainer ring 30 is axially moved through threaded engagement. The retainer ring 30 is provided on the upstream end surface with a plurality of recesses 32. A suitable tool (not shown) may be engaged with the recesses 32 to rotate the retainer ring 30 to axially move it back and forth. This structure is assembled by first inserting the orifice disk 10 into the bore of the cylindrical body 1 from the right in FIG. 1. On course, the O-ring 12 is previously fitted on the orifice disk 10. Then the spacer 21 is inserted into the cylindrical body bore. Preferably the partition 20 is secured to the spacer 21 as by welding before the spacer 21 is inserted such that the open portion below the partition 20 comes in axial alignment with the large orifice 13 as shown in FIG. 3. Next, the other spacer 27 is inserted into the bore and the retainer ring 30 is threadably engaged therein. Assembly is complete when the downstream end of the orifice disk 10 abuts against the step 3 and the end surface 34 of the retainer ring 30 is approximately flush with the upstream flange surface of the cylindrical body 1. It is evident that the structure can be disassembled by reversely following the procedure. This embodiment is used as shown in FIG. 4. The condensate drainage apparatus D is connected between upstream and downstream conduit sections B such that the axis of the apparatus extends horizontally and the large orifice 13 is located at the lowest. If a condensate d forms in a lower portion of the upstream pipe section B, the condensate d flows horizontally through the section B along its bottom together with some steam S. Then the condensate d flows past the open lower portion of the cylindrical casing 1 below the partition 20 and is then drained through the large orifice 13. Since the steam S stays in a relatively upper space in the conduit section B and the apparatus D, further downstream flow of steam is prevented by the partition 20. Thus only a minimal amount of steam can escape. Even when a foreign matter is present in the condensate d , it is conveyed outside along with the condensate through the large orifice 13. Since the orifice 13 has a relatively large diameter, a certain amount of condensate can be drained through this orifice 13. When a more amount of condensate forms, it can be drained through upper orificies 14, 15 and 16 in addition to the orifice 13. In one example, the cylindrical body 1 has an inner diamters of 80 mm, the large orifice 13 has a diameter of 16 mm, the orifices 14 have a diameter of 8 mm, the orifice 15 has a diameter of 6 mm, and the orifices 16 have a diameter of 7 mm. Under a steam pressure of 0.45 kg/cm²-G (1 kg/cm² = 0.98 bar), a back pressure of 0.20 kg/cm²-G, and a pressure head of 0.25 kg/cm²-G, the amount of condensate which can be drained through the apparatus ranges from 6 to 4.8 ton/hour depending on the leakage amount of steam. FIGS. 5 and 6 illustrate another embodiment of the apparatus according to the first type. In this embodiment, first and second partitions 35 and 37 are located upstream of an orifice disk 36 in a flowpath 38 of a flanged cylindrical casing. The first partition 35 extends vertically downward from the top and terminates at a lower edge while the second partition 37 is positioned below and extends perpendicular to the central axis of the flowpath 38. A lower portion of the second partition 37 is provided with a cut-out 39 through which liquid or fine particles can pass. The second partition 37 has a lower edge which is vertically located below the lower edge of the first partition 35. This arrangement allows steam to pass through the flowpath 38 until the surface of incoming liquid from the right side in FIG. 5 reaches the lower edge of the first partition 35. After the surface of liquid rises beyond the lower edge of the first partition 35, the steam path is closed. Then the internal steam pressure increases so that steam may eventually flush out while flooding the liquid. This embodiment has the advantage that the available cross-sectional area of the steam flowpath can be controlled to be wide or narrow or to be high or low in a vertical direction by properly setting the two partitions. With a single partition, the controllable range is limited. The foregoing embodiments of the present invention are suitable for horizontal placement. Since a lower one among a plurality of orificies perforated in the orifice disk generally has a large diameter and the partition having only a lower portion opened is located upstream of the orifice disk, a great amount of condensate can be drained through the lower portion of the partition and then the large diameter orifice. At the same time, the partition prevents steam from escaping. Since the orifice disk and the partition are mounted within the cylindrical casing, the entire apparatus is compact and convenient to handle. Foreign matters such as rust, scale and dust are readily conveyed with the draining condensate. It is possible that the lower orifice has the same diameter as the upper orifices. These embodiments can be placed in a vertical position without changing the orifice diameter. The exact positions where a plurality of orifices are located on the orifice disk depend on a particular embodiment. In an embodiment suitable for vertical placement, an orifice disk having orifices of an equal diameter located at an equal spacing is suitable for most applications. Next, the apparatus according to a second type is described. The apparatus according to the second type ensures that condensate is drained through orifices by changing the lift of the valve plug traversing the flowpath to change the number of available orifices so as to meet the flow rate of condensate while the valve prevents leakage of steam. The orifice disk may be mounted in a casing adjacent the valve plug in several ways. That is, an orifice disk may be located upstream or downstream of the valve plug, or two orifice disks are located both upstream and downstream of the valve plug. It is also possible to locate more than two orifice disks. The apparatus according to the second aspect can be readily incorporated at a location which experiences a substantial change in flow rate of condensate or in a steam equipment in which the flow rate of condensate is not exactly estimated because the apparatus can be operated under efficient conditions by post adjustments. When the flow rate of condensate is zero, the valve plug is moved to its full close position so that the valve may function as a shut-off valve. In the practice of the present invention, the components including the casing, valve plug, and orifice disk are preferably formed of stainless steel. It is preferred that a plurality of orifices have an equal diameter and are arranged in symmetry with respect to vertical and horizontal lines passing the axis of the disk and at an equal spacing. Referring to FIGS. 7 through 11, there is illustrated the apparatus according to the second type. In FIGS. 7 and 8, the condensate drainage apparatus includes a horizontally placed sluice valve generally designated at 101 defining a flowpath 103 and an orifice disk 107 mounted in the flowpath 103. The sluice valve 101 is substantially designed according to the Japanese Industrial Standard. The valve 101 includes a casing 102 defining a flowpath 103 of a circular cross section and having flanges 102a and 102b at opposed ends. A valve plug 104 is received in a recess 105 in the casing 102 so as to traverse the flowpath from above. The valve plug 104 is connected to a valve stem 106 so that the plug may be lifted by the stem. The sluice valve 101 may be directly or indirectly connected to a steam equipment or conduit through the flanges 102a and 102b such that the flange 102a is upstream and fluid flows in an arrowed direction. The orifice disk 107 is disposed in the bore of the casing 102 adjacent to, preferably in close contact with a downstream radially extending rim defining the recess 105. The orifice disk 107 is fixedly secured to the casing 102 in an oblique orientation such that an upper portion of the disk 107 is tilted in a downstream direction. The orifice disk 107 is formed with six orifices 108 having an equal diameter which are located in symmetry with respect to vertical and horizontal lines crossing the axis and at an equal spacing. The operation of the embodiment shown in FIGS. 7 and 8 will be described. FIG. 9 shows the apparatus in which the valve plug 104 is slided upward about one third (1/3) of its entire lift so as to meet the flow rate of condensate. In this state, the condensate passes through the flow path 103 together with some steam along the bottom wall in a horizontal direction. Then the condensate enters the open space which is kept open below the valve plug 104 and leaves the casing through the lower pair of orifices 108. On the other hand, the valve plus 104 prevents passage of steam which occupies a relatively upper space of the flow path 103. Therefore, only a limited amount of steam can leak out of the apparatus. When the flow rate of condensate is greater, the valve plug 104 is further slided upward so that the condensate will pass through the first and second pairs of orifices 108. To accommodate for the maximum flow rate of condensate, the valve plug 104 is lifted to the highest position shown by dot-and-dash lines so that the condensate will be drained through all the orifices 108. It is to be understood that when the flow rate of condensate is zero, the lift of the valve plug 104 is controlled to be zero, that is, the valve plug 104 is pushed down to the rest position to interrupt the flow path 103. The valve functions as a shut-off valve in this condition. Other embodiments of the present invention are illustrated in FIGS. 10 and 11. FIG. 10 shows the embodiment wherein the orifice disk 107 is located upstream of the valve plug 104. FIG. 11 shows the embodiment wherein two orifice disks 107 are located upstream and downstream of the valve plug 104. In the apparatus according to the second type, the flow path is interfered from above by the valve plug in accordance with a particular flow rate of condensate while the valve plug prevents leakage of steam. As shown in the first type, the lowermost one of the orifices in the orifice disk may have the largest diameter.

Claims: Apparatus for use in draining condensate (d) from equipment which, in use, contains a vapour, comprising a casing (2) to be connected in fluid communication with the equipment and defining a flow path for vapour (s) and condensate (d), means defining at least one orifice for restricting the flow path, and a partition (20, 35, 37) disposed in said casing (2) at a predetermined spacing from said means defining an orifice and extending downwardly into the flow path to close a predetermined portion of the flow path (13, 16), characterised in that said flow path is generally rectilinear and in that said means comprises a plate member (10) disposed in said casing (2) transverse to the flow path and having at least one orifice (13, 14, 15, 16) formed therein. Apparatus according to claim 1, characterised by a plurality of partitions (35, 37) disposed in said casing (2) wherein when the casing (2) is oriented so that a first partition (35) closes an upper portion of the flow path, a second partition (37), upstream of said first partition (35) has a lower edge lower than a lower edge of the first partition (35). An apparatus according to claim 1, characterised in that the casing is a sluice valve casing (101) and partition comprises a valve element (104) movably mounted in said casing (101) to project downwardly into the flow path and to controllably restrict the flow path. Apparatus according to claim 3, characterised in that the valve element (104) is arranged to move transverse to the flow path. Apparatus according to any preceding claim, characterised in that when the apparatus is oriented for use the lowermost one of a plurality of orifices (108) in the member (107) has the largest diameter.

Inventors: HIGASHINO, HIROKI, SEKI, MASAO
Applicants: CILUCK CO. LTD., MITSUI PETROCHEMICAL INDUSTRIES, LTD.
Application year: 1988
Main classification: F16T1
IPC codes: F16T1