Thermally-actuated steam trap

Abstract: In order to open a valve member (17) during the breakage of a temperature control element (41), there is provided a thermally-actuated steam trap comprising: a valve casing (1,2) having an inlet (6), a valve chest (4) and an outlet (7), a valve seat member (9) having a discharge passage between the valve chest (4) and the outlet (7), a temperature control element (41) disposed in the valve chest (4) and including a cover member (14), a diaphragm (42), and a valve member (17) and containing expansible medium, and a through hole (47) in the valve member (17) through which a face of the diaphragm (42) being not in contact with the expansible medium communicates with the discharge passage. An introducing passage, through which a space formed between the valve seat member and the diaphragm (42) communicates with the valve chest (4), and the discharge passage is provided in the valve seat member (9), and the valve member (17) is disposed in said space.

Description: The present invention relates to a steam trap to automatically discharge condensate generated in various kinds of steam using equipments and steam pipe lines, and more particulary to a thermally-actuated steam trap adapted to discharge the condensate of below a desired temperature out of a system by using a temperature control element including medium which is heated and cooled by steam and condensate, and expanded and contracted in accordance with the temperature thereof. The basic construction of a thermally-actuated steam trap has been well-known, as disclosed in, for example, Japanese examined patent publication No. 60-46318. As understood from this publication, the thermally-actuated steam trap comprises a temperature control element obtained by filling expansible medium in an inner space formed by securing the outer peripheral edges of a disk-like wall member and a diaphragm to each other, a valve chest communicating with an inlet in which the temperature control element is provided, a valve member connected to the diaphragm, provided in the valve chest and driven by employing the expansion and contraction of the expansible medium and a valve seat member having a discharge passage through which the valve chest communicates with an outlet, on and from which the valve member is seated and separated. When the steam of high temperature enters the valve chest, the expansible medium expands, so that the valve member is seated on the valve seat member to thereby close the discharge passage. Accordingly, the discharge of the steam is prevented. When the condensate of low temperature enters, the expansible medium is contracted and the valve member is separated from the valve seat member to thereby open the discharge passage. Thus, the condensate is discharged out of a system. Such a thermally actuated steam trap, as defined in the first part of claim 1, is known from DE-A-3 124 664. However, in the thermally-actuated steam trap of such a type, in the case where the temperature control element is broken and the expansible medium flows out, the valve member is seated on the valve seat member due to the fluid pressure of the inlet side to thereby close the discharge passage. When the valve member closes the passage upon the breakage of the temperature control element, such problems may arise that the condensate cannot be discharged, and therefore, the operating efficiency of a steam using equipment is deteriorated, defective articles are produced or water hammer phenomenon is caused, which results in breaking equipments or pipelines. An object of the present invention is to open a valve member during the breakage of a temperature control element. In order to achieve the above-mentioned object, according to the present invention, is provided a thermally-actuated steam trap as defined in claim 1. According to such a construction, when the temperature of fluid entering the valve chest from the inlet is high, the expansible medium contained between the cover member and the diaphragm expands so that the valve member is displaced to close the introducing passage and prevents the high temperature fluid, that is, steam from flowing out. On the other hand, when low temperature fluid enters the valve chest, the expansible medium contracts, the valve member is separated from the introducing passage so that the low temperature fluid is discharged to the outlet. The space in which the valve member is disposed communicates with the outlet through the discharge passage. Since the fluid pressure at the inlet side is so exerted on the valve member from the introducing passage as to open the valve member, when the temperature control element is broken, the valve member is separated from the introducing passage to open. Other features and advantages of the present invention will be apparent from the following description taken in connection with the accompanying drawings, wherein Fig. 1 is a thermally-actuated steam trap according to an embodiment of the present invention, Fig. 2 is a sectional view of a valve seat member shown in Fig. 1, Fig. 3 is a sectional view of a thermally-actuated steam trap with a valve seat member and a valve member of different construction, and Fig. 4 is a sectional view of the valve seat member shown in Fig. 3. The present invention will now be described in more detail in connection with embodiments. With reference to Fig. 1, an upper casing 1 and a lower casing 2 are fastened to each other by means of bolts 3 to form a valve casing having a valve chest 4 therein. Airtightmess between both the casings 1 and 2 is maintained by means of an annular gasket 5. An inlet 6 is formed in the upper casing 1 and an outlet 7 is formed in the lower casing 2. A temperature control element 41 comprises a cover member 14, a diaphragm 42, a valve member 17 and an annular spacer 43. Expansible liquid 19 is injected into a space formed by the cover member 14 and the diaphragm 42. The space is sealed by closing the injection port 21. The expansible liquid 19 is water liquid whose boiling point is lower than that of water or the mixture thereof. A valve seat member 9 threaded and connected to a partition wall 8 between a valve chest 4 and an outlet 7 and the spacer 43 disposed on the upper face thereof are secured by welding their outer peripheral edges which are mutually in contact. The spacer 43, the diaphragm 42 and the cover member 14 are secured to one another by welding their outer peripheral edges which are mutually in contact. A disk-like valve member 17 recessed at a part near to the center on its upper face is disposed in a space formed by the valve seat member 9, the annular spacer 43 and the diaphragm 42. The valve member 17 has a central penetrating through hole 47. The diaphragm 42 and the valve member 17 are secured by welding the diaphragm 42 to the upper and outer peripheral face of the valve member 17. In the valve seat member 9 is bored a discharge passage 44 at its central portion, through which a space formed by the valve seat member 9, the annular spacer 43 and the diaphragm 42 communicates with the outlet 7. On the circumference of the upper face thereof, is formed an annular slot 45. As apparent from Figs. 1 and 2, four passages 46 are opened and extend sideward from the annular slot 45 so that introducing passages through which the valve chest 4 communicates with a space formed by the valve seat member 9, the annular spacer 43 and the diaphragm 42. The outside diameter of the lower face of the valve member 17 is larger than that of the annular slot 45. The diameter of the through hole 47 is smaller than the inside diameter of the annular slot 45 and further than the diameter of the discharge passage 44. Accordingly, when the valve member 17 is seated on the valve seat member 9, it closes the introducing passages 45, 46, however, does not close the discharge passage 44. When the temperature of fluid entering the valve chest 4 from the inlet 6 is high, expansible medium 19 expands to thereby displace the valve member 17 downward through the diaphragm 42 and seat the valve member 17 on the valve seat member 9, so that the introducing passages 45 and 46 are closed, and the high temperature fluid, namely, steam is prevented from flowing out. When the temperature of fluid becomes lower than a prescribed value, due to radiation or the like, the expansible medium 19 contracts and the valve member 17 is separated from the valve seat member 9, with the addition of fluid pressure, so that the introducing passages 45 and 46 are opened to discharge the low temperature fluid, that is, low temperature condensate out of a system from the outlet 7. In the case where the diaphragm 42 is broken, the space filled with the expansible medium 19 communicates with the outlet 7 through the through hole 47 and the discharge passage 44. The expansible medium 19 is, therefore, discharged to the outlet 7. The valve member 17 is forced upward together with the diaphragm 42 due to the fluid pressure of the inlet side, separated from the valve seat member 9 and opens the discharge passage 44 to thereby open the valve. It will be noted that two diaphragms may be provided and the diaphragm at the valve member side has an aperture in the steam trap of the above-mentioned construction, so that the counterflow of the fluid of the outlet side can be prevented. In Fig. 3 still another embodiment of a steam trap with a valve seat member of different construction is illustrated. As can be seen from Figs. 3 and 4, on a valve seat member 9, three sideward passages 51 and a central passage 52 are formed. These introducing passages communicate with spaces formed by a valve chest 4, the valve seat member 9, an annular spacer 43 and a diaphragm 42. On the circumference of the upper face of the passage 52, is opened an annular slot 53. From this annular slot 53, are opened three passages 54 downward. Thus, discharge passages through which a space formed by the valve seat member 9, the annular spacer 43 and the diaphragm 42 communicates with an outlet 7 are formed. The outside diameter of the lower face of a valve member 17 is a little smaller than the outside diameter of the annular slot 53. Therefore, when the valve member 17 is seated on the valve seat member 9, it closes the introducing passages 51 and 52, however, does not close the discharge passages 53 and 54. The diaphragm 42 and the valve member 17 are connected to each other by respectively welding at their central parts.

Claims: A thermally-actuated steam trap comprising: a valve casing (1,2) having an inlet (6), a valve chest (4) and an outlet (7), a valve seat member (9) disposed between the valve chest (4) and the outlet, a temperature control element (41) disposed in the valve chest (4) and adjacently to the valve seat member (9) and including a cover member (14), a diaphragm (42) and a valve member (17) and further containing expansible medium, at least one introducing passage (45,46;51,52) through which a space formed between the valve seat member (9) and the diaphragm (42) communicates with the valve chest (4), and at least one discharge passage (44;53,54) through which said space communicates with the outlet (7), said introducing passage and the discharge passage being provided in the valve seat member (9), and said valve member (17) being disposed in said space, characterized in that said valve member (17) is designed for opening and closing the at least one introducing passage (45,46;51,52), so that when the valve member (17) is seated on the valve seat member (9) it closes the introducing passage (45,46;51,52). A thermally-actuated steam trap according to claim 1, wherein in the seated position the valve member (17) closes only the introducing passage (45,46;51,52) and leaves the discharge passage (44;53,54) open. A thermally-actuated steam trap according to claim 1 or 2, wherein said temperature control element (41) comprises the cover member (14), the diaphragm (42), the valve member (17) and an annular spacer (43), said annular spacer (43) secured to the upper face of said valve seat member (9), the diaphragm (42) and the cover member (14) are secured at their outer peripheral edges which are mutually in contact, the valve member (17) having a through hole is disposed in a space formed by the valve seat member (9), the annular spacer (43) and the diaphragm (42), said valve member (17) is secured to the diaphragm (42), a discharge passage (44) through which said space communicates with an outlet (7) is bored in the central part of the valve seat member (9) and introducing passages through which said space communicates with the valve chest (4) are opened on the circumference thereof. A thermally-actuated steam trap according to claim 1 or 2, wherein said temperature control element comprises the cover member (14), the diaphragm (42), the valve member (17) and an annular spacer (43), the annular spacer (43) secured to the upper face of said valve seat member (9), the diaphragm (42) and the cover member (14) are secured at their outer peripheral edges which are mutually in contact, the valve member (17) secured to the diaphragm (42) is disposed in a space formed by the valve seat member (9), the annular spacer (43) and the diaphragm (42), an introducing passage through which said space communicates with a valve chest (4) is opened on the central part of the upper face of the valve seat member (9), discharge passages through which said space communicates with an outlet (7) are opened on the circumference thereof, and when the valve member (17) is seated, only the introducing passage is closed.

Inventors: YUMOTO HIDEAKI, YUMOTO, HIDEAKI
Applicants: TLV CO LTD, TLV CO. LTD.
Application year: 1992
Main classification: F16T1
IPC codes: F16T1