Free float steam trap

Abstract: A free float steam trap comprises a trap casing having an inlet port (51) and an outlet port (52) and a valve chest (56) formed therein, a valve seat member (57) attached to the lower portion of the valve chest (56) and having a valve orifice (65) opened through which the valve chest (56) communicates with the outlet port (52), a float valve (70) arranged in a free state in the valve chest (56), rising and descending in accordance with the water level in the valve chest (56) to directly open and close the valve orifice (65) and a means for dispersing and passing condensate flow downward, provided at a fluid inlet (59) through which the inlet port communicates with the valve chest (56).

Description: The present invention relates to a free float steam trap adapted to directly open and close a valve orifice by a float valve accommodated in a free state in a valve chest, thereby automatically discharging only condensate from the mixture of steam and the condensate, based on a basic concept that the difference in specific gravity between the steam and the condensate is employed. For example, a free float steam trap disclosed in Japanese unexamined patent publication No. 55135292 is provided with a spherical float inside which rises due to buoyancy and descends in a free state in a valve chest and also has a function of valve body. The steam trap of this type is provided with a single operating portion in comparison with a conventional steam trap in which a float, a lever and a valve body are individually separate, and its structure is extremely simple, so that there occurs little trouble. Furthermore, since the entire surface of its float valve put in a free state forms a seal surface, a new valve surface can be easily obtained relative to a valve seat. The construction of the conventional free float steam trap is shown in Fig. 5. A trap casing is constituted by attaching a cover member 93 to a main body 90 having an inlet port 91 and an outlet port 92. A valve chest 94 is formed in the interior portion thereof. A float valve 95 is accommodated in a free state in the valve chest 94. A valve seat member 96 is mounted on a lower portion of the valve chest 94 and held by a plug 97. At the valve seat member 96 is formed a valve orifice 98 opened to the valve chest 94. The valve orifice 98 communicates with the outlet port 92 through an outlet passage 99. Condensate entering from the inlet port 91 stays in the valve chest 94. The float valve 95 rises and descends due to buoyancy in accordance with the water level thereof so that the valve orifice 98 is opened and closed. The opening of the valve orifice enables the condensate in the valve chest 94 to be discharged and flown to the outlet port 92 through the outlet passage 99. Fig. 6 is a sectional view substantially taken along a line A-A in Fig. 5, showing a condition that the condensate flows into the valve chest 94 from the inlet port 91. As understood from the figure, the sectional configuration of an inlet for condensate which indicates an inlet portion, and a portion for connecting the inlet port to the valve chest is generally designed to be circular because of the connection to a pipe arrangement. When the condensate flows in this portion, therefore, the condensate flow is gathered at a portion close to a central portion of the inlet port, as shown in the figure, then, becomes a thin water flow and flows down to the valve chest. In the free float steam trap as mentioned above, the float valve is arranged in a free state in the valve chest, so that there originally arises such a defect that the float valve is liable to be vibrated. Therefore, when the condensatet flow falls in a concentrated manner, as mentioned above, the float valve arranged at the destination of a fall of the condensate flow is significantly vibrated due to the action of the condensate flow. As a result, the contact between the float valve and the valve orifice is deteriorated, so that the leakage of fluid, specially, steam in the valve chest occurs. When the condensate flows into the valve chest 94 from the inlet port 91 in a state as shown by an arrow X in Fig. 5, the condensate so exerts as to press the float valve 95 to the valve orifice 98 so that the float valve 95 is prevented from opening. As a result, there arises a problem that the discharge flow rate of the condensate is decreased. On the other hand, when the condensate concentrically falls on the valve orifice side, the fluid in the vicinity of the valve orifice is brought into a turbulent state. Therefore, there arises such a problem that steam is liable to be involved in the fluid flowing out to the outlet port through the valve orifice. Further, when the condensate falling in a concentrated manner is even slightly deflected from the center line of the float valve, namely, the axis of the valve orifice, the condensate flow so actuates as to push the float valve sideward. Consequently, the float valve is turned away from the valve orifice and the leakage of the fluid, especially, steam is induced. Accordingly, a technical object of the present invention resides in that the float valve is hardly affected by flowing condensate in a free float steam trap. An object of the present invention is to weaken the impact force of condensate falling on a valve chest which is exerted on a float valve, whereby the vibration of the float valve is supressed so that a sealing property between the float valve and a valve seat (valve orifice) is improved and the leakage of steam is prevented. Another object of the present invention is to restrict the turbulent state of fluid present in the vicinity of the valve orifice so that the involving of steam in the outflow fluid can be prevented. In order to achieve these objects, the subject matter of the present invention resides in a free float steam trap comprising a combination of the characteristics disclosed in Patent Claim 1. According to the present invention, the condensate entering the valve chest from the inlet port is dispersed and falls by means of a dispersing means. The impact force of the condensate imposed on the float valve is, therefore, dispersed, so that the vibration of the float valve is controlled. 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 an end view of a free float steam trap showing an embodiment of the present invention; Fig. 2 is a sectional view substantially taken along a line D-D in Fig. 1; Fig. 3 is a sectional view showing another form of a dam in Fig. 2; Fig. 4 is an end view taken along a line E-E in Fig.1; Fig. 5 is an end view of a well-known free float steam trap and Fig. 6 is a sectional view taken along a line A-A in Fig. 5. The present invention will now be described in detail with reference to a preferred embodiment shown in the drawings. As illustrated in Fig. 1, a cover 54 is fixed to a main body 50 having an inlet port 51 at an upper portion and an outlet port 52 at a lower portion through a gasket 53 by means of bolts to form a trap casing. A valve chest 56 is formed in an interior portion thereof. The inlet port 51 and the outlet port 52 are horizontally opened and respectively provided with internally threaded portions for pipe arrangements. A fluid inlet 59 through which the inlet port 51 communicates with the valve chest 56 is located in a space above a valve seat member 57 mentioned below. In the fluid inlet 59 is formed an overall width dam 58 which is slightly inclined toward the valve chest side. The height of the dam 58 is approximately half of the diameter of the inlet port 51 or the fluid inlet 59. The inclination of the dam is preferably about 5 to 15° with respect to a vertical line, however, it may not be limited thereto. The valve seat member 57 having a valve orifice 65 is affixed to the lower side face of the valve chest 56 by means of threaded members. A hollow and sperical float 70 is accommodated in a free state in the valve chest 56. On the bottom face of the valve 56, two float seats 71,72 are so formed as to be substantially parallel with the central axis of the valve orifice 65. As a result, when the float valve 70 descends as condensate in the valve chest 56 decreases to close the valve orifice 65, the float valve 70 abuts on the three points 71',72',57' (see Fig. 4) of the float seats 71,72 and the tip end of the valve seat member 57, so that a completely sealed state is achieved. The condensate flowing out of the inlet port 51 is stopped by the overall width dam 58 until it reaches the height thereof. When the amount of the condensate reaches such an amount as to exceed the height of the dam, the condensate crosses the dam 58, is dispersed and flows into the valve chest 56. In order to improve the dispersing effect for the condensate, many slits may be provided at the upper edge portion of a dam 60, as shown in Fig. 3. Reference numeral 76 designates a bimetal strip. The above-mentioned free float steam trap according to the present invention operates as follows. The condensate entering from the inlet port 51 is stored to the height of the overwall width dam 58. The condensate further entering, therefrom crosses the dam 58, is dispersed and flows into the valve chest 56, as shown in Fig. 2. As a result, the impact force of the condensate imposed on the float valve 70 is weakened, so that the vibration of the float valve 70 is restricted. Since the condensate does not flow down to a portion close to the valve orifice in a concentrated manner, the turbulent flow of the fluid in the vicinity of the valve orifice is restricted. Therefore, steam is hard to be involved in the outflow fluid. Further, since the dispersed and flowing condensate strikes the surface of the float valve 70 which is closer to the valve orifice 65 side than a perpendicular passing through the center of the float valve 70 in the drawing, the condensate does not press the float valve to the valve orifice 65. Therefore, the interference of the valve opening operation of the float valve 70 can be avoided, and accordingly, the condensate can be smoothly discharged.

Claims: A free float steam trap comprising: a trap casing (50) having an inlet port (51), an outlet port (52) and a valve chest (56) formed therein; a valve seat member (57) attached to the lower portion of the valve chest (56) and having a valve orifice (65) through which the valve chest (56) communicates with the outlet port (52); a float valve (70) arranged in a free state in the valve chest (56), rising and descending in accordance with the water level in the valve chest (56) to directly open and close the valve orifice (65); and characterised by a means for dispersing and passing condensate flow downward having an upwardly directed end wall spaced from an upper inner surface of the trap casing to form a reservoir, wherein the dispersing means is an overall width dam (58,60) which is located substantially above the valve orifice (65) and which is provided in a fluid inlet (59) through which the inlet port (51) communicates with the valve chest (56). A steam trap according to claim 1, characterized in that the overall width dam (60) has many irregularities on the upper end portion thereof.

Inventors: OIKE TADASHI, OIKE, TADASHI
Applicants: TLV CO LTD, TLV CO. LTD.
Application year: 1991
Main classification: F16T1
IPC codes: F16T1