Self-venting drain valve assembly

Abstract: A self-venting valve apparatus using a valve stem (16) rotatably and slidably mounted to a vessel (4) by a collar (8) is disclosed. The stem includes threads at the top (36) and base (34) of the stem which matingly engage internal threads (10) of the collar to hold the stem open or closed. A single gasket (46) seals the gas inlet and liquid outlet in the closed configuration. To drain the fluid, the valve stem is unscrewed so the bottom threads disengage from the collar, the valve stem lowers until the top threads of the valve stem engage the collar, and the top threads are screwed to the collar to secure the valve in the open position. Fluid begins draining through the central passage (38) of the valve stem (16) before gas enters the vessel through the groove (20) in the sidewall of the valve stem to allow proper siphoning. The lower end of the liquid drain passage is placed below the lower end of the air inlet groove, thereby insuring that the liquid drain passage is opened first as the valve stem is lowered. Entering air is isolated from the outgoing water by a riser wall (44) which separates the passage from the groove. The liquid drains through the passage and then exits into a collector knob. The collector knob maintains a regulated and controlled flow resistance through a drain spout.

Description: This invention relates to a self-venting valve assembly for draining liquid from a vessel in which the liquid within the vessel may be subjected to a vacuum, and in particular to a valve assembly with the features of the pre-characterizing part of claim 1. Self-venting liquid drain valves have been known in the art for many years. Specifically, various assemblies have been made to provide fluid drainage from a vessel while providing a separate inlet for gas, such as air, to replace the fluid being drained. For example, in fuel/water separators used in diesel engines, water must be periodically drained using a valve assembly adapted to feed air into a separator while the water is being drained. The prior art devices have accomplished this by providing separate air and liquid paths formed through a portion of the valve assembly member. US - A - 4,724,074 as the starting point of the invention discloses a self-venting valve assembly for draining liquid from a vessel which is constructed to open a liquid path prior to opening an air path and to close the paths in reverse order. Both paths are separated from each other by a separation wall within a valve body or stem. For the closed position two seals are absolutely necessary, i. e. an internal seal cooperating with an upper vent wall to block the gas flow path as well as with an upper edge of the stem to block the liquid flow path, and a peripheral seal by an O-ring to effectively block any liquid flow around the stem (valve body) through the opening in the bottom of the vessel. It is described as an important feature how an intermediate position is achieved in which air is drawn into the cavity to clear the zone around the vent port at the upper end of the gas path before this path is opened. This important feature makes both sealing means compulsory. US - A - 4,440,193 discloses a valve assembly for draining a liquid including a valve housing or body member adapted to receive a threaded valve piece rotatably movable between open and closed positions. An air intake passage is contained within the body member separate from the liquid drain passage contained in movable valve piece. This type of arrangement requires separate sealing means for the air intake passage and liquid drain passage as well. US - A - 4,708,171 attempted to simplify the prior art valves by including both the air inlet and liquid passages in a single valve member rotatable between open and closed positions. However, the drain valve disclosed in US - A - 4,708,171 requires a rather complicated valve housing secured to a vacuum vessel and adapted to provide a close fit between the housing and the valve member to ensure proper liquid drainage through radially extending openings at the upper end of the housing. The air inlet passage also requires a sealing point within the housing to prevent gas from entering the vessel when the valve assembly is closed. US - A - 4,611,627 discloses a self-venting drain valve with a valve portion movable relative to a housing including an air intake and a water passage outlet. This device as well requires at least two different seals, and the intake passage is provided entirely within the non-moving housing. US - A - 3,044,504 discloses a valve with an axial opening which bends degrees to the side and a second passage. However, this device is directed to an injector valve that requires at least two seals. US - A - 4,753,266 discloses another valve assembly having two passages, one for draining liquid and another serving as an air vent. A valve member is rotatably mounted on body member, but the rotation is limited to 90°. The valve member rotates so that its passages engage passages, when the valve is open. Three O-ring seals are used to seal the two passages and the valve assembly to the vessel. As can be seen from above description the self-venting feature in the prior art is achieved by a structure which is still rather complicated and expensive to manufacture. The present invention therefore has as its object to provide a self-venting valve assembly for draining liquid from a vessel which is simple in construction and inexpensive to manufacture. Above object is achieved by the valve assembly defined in claim 1. With the idea to position the lower end of the liquid path vertically below the lower end of the gas path the inlet of the gas path can be out of communication with the exterior of the vessel in the closed position. Thus in the closed position only the lower end of the liquid path must be sealingly blocked against the bottom of the vessel or body portion of the valve assembly respectively. This means that only one single gasket is sufficient to effectively block both paths in the closed position of the valve assembly. Of course, in the open position of the valve assembly it is easily acceptable that a small amount of fluid may drain around the stem, because most of the fluid will drain through the liquid path anyway. The fact that one complete sealing means could be disposed of greatly simplifies the construction of the valve assembly according to the invention. Further improvements of the inventive self-venting valve assembly are described by the features of the dependent claims 2 to 26. As to some of those dependent claims particular comments are given below. The gasket of claim 6 trapped between a collar attached to the vessel and the base of the valve stem provides the single seal for both the liquid and gas when the valve apparatus is closed. In a preferred embodiment of claim 17 a simple, self-venting apparatus for draining liquid from a vessel is provided including an operator knob which can be snapped onto the base of the valve to provide a cup or reservoir to collect liquid being drained from the vessel and to provide constant flow resistance during liquid drainage. The liquid drain outlet should be vertically separated from the air inlet by a distance of at least approximately 2,54 cm (1,00 in) to facilitate proper siphoning. For a better understanding of the invention and its advantages, reference should be made to the accompanying drawings and descriptive matter which illustrate and describe preferred embodiments of the invention. Figure 1 is a cross-sectional view of the self-venting drain valve assembly of the present invention with the assembly in the closed position. Figure 2 is a cross-sectional view of the self-venting drain valve assembly of Figure 1 with the assembly in the open position. Figure 3 is a perspective view of the valve stem of the valve assembly. Figure 4 is a cross-sectional view of the collar element of the valve assembly. Figures 5 and 6 are additional side elevational views of the valve stem. Figure 7 is a cross-sectional view of the valve stem taken along lines 7-7 of Figures 5 and 6. Figures 8 and 9 are top and bottom elevational views of the valve stem. Figure 10 is a top elevational view of the valve operator. Figure 11 is a cross-sectional view of the valve operator taken along line 11-11 of Figure 10. Figure 12 is a bottom elevational view of the valve operator. Figure 13 is a perspective view of the valve operator. Figure 14 is a top perspective view of another embodiment of the valve operator. Figure 15 is a bottom perspective view of the valve operator of Figure 14. Figure 16 is a top view of the valve operator of Figure 14. Figure 17 is a perspective view of another embodiment of valve stem. Figure 18 is a top view of the valve stem of Figure 17. Figure 19 is a bottom perspective view of the valve operator connected to the valve stem of Figures 14-18. For a more complete understanding of the subject invention, reference is now made to Figure 1, showing a cross-sectional view of a specific self-venting valve assembly. The disclosed valve assembly 2 is illustrated in combination with a vessel 4 which may be a portion of the housing of a water/fuel separator. Such separators are frequently installed on the vacuum side of a fuel pump, thereby subjecting the interior of vessel 4 to sub-atmospheric pressure. A compression spring 6 operates to properly position a filter (not illustrated) within the water/fuel separator as is explained more fully in US - A - 4,440,193. During operation of a water/fuel separator, water accumulates in the bottom portion of vessel 4 and must be drained periodically to permit continued satisfactory operation of the separator. To perform this function, valve assembly 2 provides a drain path through which water collected in the base of vessel 4 may be drained out of the vessel while providing a passage for air to enter vessel 4 simultaneously to break the vacuum within the vessel and facilitate drainage. As will be explained more fully below, the valve assembly 2 described herein provides a self-venting feature by a structure which is comparatively simple and inexpensive to manufacture as compared with prior art designs. Self-venting valve assembly 2 includes a collar or body portion 8, which may take the form of a weld nut, adapted to be welded to the bottom of vessel 4, such that the threaded opening 10 of body portion 8 aligns with an aperture 12 in the lowest portion of vessel 4. A valve element 14 is positioned for reciprocating movement within threaded opening 10 of body portion 8 between a closed position, as illustrated in Figure 1, and an open position, shown in Figure 2. In the open position, gas enters and liquid drains from vessel 4 along separate paths. Valve element 14 is formed by a stem 16 containing an internal passage 18 through which liquid such as water may drain from vessel 4. On its exterior, stem 16 is provided with an axially extending groove 20 through which air can enter vessel 4. Valve element 14 also includes valve base portion 22 formed at the bottom of valve stem 16. Base portion 22 includes a radial flange 24 and peripheral skirt 26. Peripheral skirt 26 includes a series of reinforcing ribs 26a as will be described below with reference to Figure 9. Valve assembly 2 further includes a collector knob or operator 32 which is disposed around base portion 22 of valve stem 16 to facilitate manual operation and to assist in draining water as will be discussed below. The lower portion of stem 16 disposed just above base portion 22 of valve element 14 includes external threads 34 which threadedly mate and are received within threaded opening 10 of body portion 8. External threads 34 engage threaded opening 10 as shown in Figure 1 when valve assembly 2 is in the closed position. When valve assembly 2 is in the open position, as shown in Figure 2, external threads 36 formed at the upper portion of stem 16 engage threaded opening 10 of body portion 8 to secure open the valve assembly. As best illustrated in Figures 1, 2, and 7, internal passage 18 includes two segments, axial passage 38 and radial passage 40. Radial passage 40 and axial passage 38 are disposed at substantially 90° right angles to each other. The upper opening to internal passage 18 is enlarged by cutaway portion 42 at the top of stem 16 substantially at the location of external threads 36. Cutaway portion 42 effectively lowers the water inlet from the top of valve stem 16 to permit air to vent into the system at a higher level than water flowing into the valve. Additionally, it has been found that the optimum ratio of the area of the water outlet to the area of the air inlet is between 4 and 5, preferably 4,6. As shown in Figure 2, the distance between the entry of air into the vessel as allowed by groove 20 and the center of radial passage 40 is indicated by a. Preferably a is at least 2.54 cm (1.00 in) long to facilitate drainage of vessel 4. With the water outlet from passage 18 at least 2.54 cm (1.00 in) below the air inlet when valve assembly 2 is open, proper siphoning of water has been found to be facilitated. It has been found that the water outlet should open slightly before the air inlet opens to provide the proper flow sequencing. This function is achieved by terminating the lower end of groove 20 well above the opening of radial passage 40 into the sidewall of stem 16. Additionally, a riser wall 44 is positioned between air passage groove 20 and cutaway portion 42 to allow water to flow into internal passage 18 at a point somewhat remote from the air flowing into vessel 4. This prevents the incoming air, in the form of bubbles, from being pulled into the out flowing water because riser wall 44 forces the air bubbles to rise upwardly away from the region of higher water velocity. Gasket 46 disposed around the bottom of stem 16 is trapped between base portion 22 and body portion 8 when valve assembly 2 is in its closed position as shown in Figure 1. Gasket 46 effectively seals both the air inlet and the water outlet when the valve assembly is in its closed configuration because the air inlet and the water outlet are inside vessel 4. Gasket 46 is the only gasket required. Thus, valve assembly 2 accomplishes the above discussed purposes and achieves the desired design criteria by using only a single sealing surface which may be formed by a lathe cut surface. The use of additional radial seals are eliminated, thereby greatly simplifying the assembly and production processes and simplifying the configuration of the valve assembly. To drain fluid from vessel 4, when valve assembly is in the closed position as shown in Figure 1, valve assembly 2 is unscrewed so that external threads 34 no longer mate with threaded opening 10. The unthreaded central portion of stem 16 drops dawn through aperture 12 at the bottom of vessel 4 and threaded opening 10 in body portion 8, until external threads 36 engage threaded opening 10 to retain the valve assembly 2 in the open position. At this point, liquid such as water in vessel 4 begins to siphon out of the vessel through cutaway portion 42 and the upper opening of internal passage 18. Water is siphoned through passage 18 because the lower portion of passage 18, radial passage 40, is lower than air inlet groove 20 disposed at the top of stem 16. As discussed above, this distance or hight, represented by a, should be at least approximately 2.54 cm (1.00 in) and is important to the proper siphoning of water from the vessel under vacuum conditions. After water exits internal passage 18 through axial passage 38 and radial passage 40, it is caught by valve operator 32 which may be a snap-on plastic knob in the form of a cup with a drain spout 30 containing an axial cylindrical passageway 31 through which the water drains. Drain spout 30 allows connection of a hose to drain fluid into a container without spillage. Additionally, valve operator 32 is cup-shaped to accumulate liquid being drained and also collects any liquid which may leak through the space between the exterior of stem 16 and the threaded opening 10. Stem 16 and valve operator 32 may be formed of die-cast zinc to permit the valve assembly to be used in marine applications. Valve operator 32 may also be formed of minlon, while body portion 8 is preferably a steel weld nut and gasket 46 is a nitrile gasket. In the embodiment of Figures 1-13, valve operator 32 is attached to valve assembly 2 before stem 16 is screwed to body portion 8 rather than being snapped-on to stem 16 after stem 16 is screwed to body portion 8. In an alternate embodiment discussed below, valve operator 32 is attached to valve assembly 2 after stem 16 is screwed to body portion 8. Reference is now specifically made to Figures 3 and 5-7 illustrating more completely the features of valve element 14. In particular, the perspective view of Figure 3 clearly illustrates that flange 24 of base portion 22 contains a substantially semi-cylindrical cutout portion 28 positioned to accommodate drain spout 30 of valve operator 32 (Figures 1 and 2). Peripheral skirt 26 is foreshortened circumferentially on either aide of cutout 28 to facilitate attachment of a drain hose (not shown) to drain spout 30. Figure 4 shows collar 8 and specifically discloses an upper circumferential rib 9 which facilitates leakproof welding of collar 8 to the bottom of vessel 4. Figures 8 and 9 disclose top and bottom views of valve element 14. In particular, Figure 9 discloses the position of reinforcing radial ribs 26a. Figures 10-13 provide additional views of operator 32 including an internal radial flange 48 having an internal opening 50 for receiving valve element 14. Operator 32 also includes a generally cylindrical outer wall 54 extending axially above internal flange 48 to form a cup-shaped reservoir for collecting liquid and directing its flow toward passageway 31 contained in drain spout 30. The portion of cylindrical outer wall 54 which extends below internal radial flange 48 includes a radially inwardly directed retaining lip 56 arranged to ride over peripheral skirt 26 and snap underneath the lower edge of skirt 26 when operator 32 is assembled with valve element 14. The outer peripheral surface of operator 32 is provided with axially oriented ribs 58 to facilitate manual gripping of the operator. Inwardly directed radial projections 60 are positioned to assist in the retention and proper placement of gasket 46. As best illustrated in Figure 13, outer wall 54 is notched out at 62 on either side of drain spout 30 to allow a hose to be fitted around the lower end of drain spout 30. In the embodiment of Figures 14-18 (elements described above retain their reference numerals and are the same except as indicated), valve operator 32' is placed around base portion 22 of stem 16 after stem 16 is screwed to body portion 8. This simplifies the manufacturing process and permits gasket retention in the closed position to be accomplished by circumferential rib 9 on body portion 8 which is slightly larger than the outer diameter of gasket 46. This prevents overtightening which may lead to gasket failure, and centers gasket 46 on body portion 8. As best shown in Figures 14-16, valve operator 32' includes two diametrically opposed inwardly projecting tabs 64 formed approximately midway along the height of outer wall 54 on the inside of wall 54. Two diametrically opposed inwardly projecting semicircular projections 66 are formed on the bottom of walls 54 midway between tabs 64. Projection 66a is solid and projection 66b is open to form part of drain spout 30. Cutout portion 28 is replaced by two diametrically opposed cutout portions 28' in base portion 22 of stem 16 as shown in Figure 17. Cutout portions 28' are disposed approximately 90° from the outlet of radial passage 40. In operation, only one cutout portion 28' communicates with drain spout 30. The other cutout portion 28' is closed by solid projection 66a. The use of two cutout portions 28' and projection 66a enables valve operator 32' to be disposed on stem 16 in either of two 180° opposed orientations so that operator 32' can easily be properly positioned on valve stem 16. Valve stem 16 also includes two diametrically opposed grooves 68 of decreasing size which end in diametrically opposed enlarged notches 70. To connect valve operator 32' to stem 16, the valve operator is placed around base portion 22 so that tabs 64 are disposed with cutout portions 28'. Valve operator 32' is then rotated so tabs 64 engage portions of grooves 68 having constantly decreasing areas which compress and secure tabs 64 until tabs 64 engage notches 70. At this point, tabs 64 expand to their original shape and are captured within notches 70 thereby securing valve operator 32' on valve stem 16. As shown in Figure 19, the bottom of valve stem 16 has a hexagonal cutout 72 to facilitate disengagement of the threaded portions of valve stem 16 from body portion 8 using a metric wrench. Therefore, as discussed above, the valve assembly of the present invention provides a simple self-venting liquid valve using only one gasket face seal to achieve the two required flows. Liquid such as water is permitted to drain while gas such as air enters the vessel being drained to facilitate drainage, even when the vessel is subjected to a vacuum. The air does not mix with the draining water in the valve assembly and it does not interfere with the draining water in the vessel. The valve assembly is relatively simple and inexpensive to manufacture because of the simplicity of design that is a significant improvement over prior art valves. The valve assembly meets all of the constraints required for self-venting fluid drainage that previously required two seals, a face seal and a radial seal: the water inlet area to air inlet area ratio is approximately 4,6; a one inch head is provided for proper siphoning; the water outlet opens before the air inlet; air is vented into the system at a level higher than the water flowing into the valve assembly; and the water and air flows are isolated from each other. The present invention finds application with vessels which require fluid drainage. This invention finds particular applicability in the drainage of fluid sumps, such as fuel water separators disposed on the vacuum side of a fuel pump in diesel engine systems. The system uses only one lathe-cut gasket face seal, thereby highly simplifying the construction and assembly of the valve while maintaining the performance of the valve.

Claims: A self-venting valve assembly (2) for draining liquid from a vessel (4), comprising a body portion (8) containing an opening (12) through which liquid may drain and gas may simultaneously enter the vessel (4) and a valve means (14) for selectively permitting and preventing flow through the opening (12), said valve means (14) containing a stem (16), a first path (18) along which the liquid may flow from the vessel (4) and a second path (20) along which the gas may enter the vessel (4), and being constructed to open the first path (18) prior to opening the second path (20) and to close the paths (18, 20) in reverse order, the first path (18) being isolated from the second path (20), characterized in that the paths (18, 20) are formed within the stem (16) or on the exterior of the stem (16), the outlet (40) of the first path (18) is vertically below the inlet of the second path (20), the inlet of the second path (20) being out of communication with the exterior of the vessel (4) in the closed position, and a single gasket seal (46) is mounted on the valve means (14) so as to be engageable with the body portion (8) or is mounted on the body portion (8) so as to be engageable with the valve means (14) in the closed position in a manner effectively preventing entry of gas and draining of liquid along the paths (18, 20) simultaneously. Assembly as set forth in claim 1, characterized in that the first path (18) is formed within the stem (16) and the second path (20) is formed by at least one groove (20) on the exterior of the stem (16) in cooperation with the body portion (8). Assembly as set forth in claim 1 or 2, characterized in that the stem (16) comprises top, bottom, and central portions and the bottom portion comprises external threads (34) which threadedly secure the stem (16) in the closed position. Assembly as set forth in claim 3, characterized in that the top portion of the stem (16) comprises external threads (36) which engage the body portion (8) and provide a point of abutment between the stem (16) and the body portion (8) when the stem (16) is in its open position, and which threadedly secure the stem (16) in the open position. Assembly as set forth in claims 3 and 4 characterized in that the body portion comprises a collar (8) attached to the vessel (4), the collar (8) comprising internal threads (10) adapted to matingly engage the external threads (34, 36) of the top and bottom portions of the stem (16) to hold the stem (16) in its open and closed positions, respectively. Assembly as set forth in one of the preceding claims, characterized in that the single gasket (46) is positioned between the stem (16) and the body portion (8) respectively. Assembly as set forth in one of the preceding claims, characterized in that the top portion of the stem (16) further comprises a riser wall (44) disposed between and separating the groove (20) from an internal axial passage (38) thereby isolating the liquid draining from the gas entering the valve means (14). Assembly as set forth in one of the preceding claims, characterized in that the first path (18) comprises an axial passage (38) opening at the top portion of the stem (16) to provide a liquid inlet into the stem (16) and a radial passage (40) opening through a sidewall at the bottom portion of the stem (16) to provide a liquid outlet from the stem (16). Assembly as set forth in claim 2 and, optionally, any of the following claims, characterized in that the stem (16) further includes a cutaway portion (42) extending downwardly from the top portion of the stem (16) and connected to an axial passage (38) of the first path (18) at the top portion of the stem (16), the cutaway portion (42) providing an effectively lower liquid entry level into the valve means (14) at the top portion of the stem (16). Assembly as set forth in one of the preceding claims, characterized in that the liquid drain level is at least 2,54 cm (1,00 in) below the gas entry level. Assembly as set forth in one of the preceding claims, characterized in that the ratio of the liquid outlet area to the gas inlet area ranges between 4 and 5. Assembly as set forth in claim 11, characterized in that the ratio of the liquid outlet area to the gas inlet area is approximately 4,6. Assembly as set forth in one of the preceding claims, characterized in that the stem (16) includes a cup-shaped base portion (22) with a radial flange (24). Assembly as set forth in claim 13 characterized in that the radial flange (24) includes a peripheral skirt (26), preferably containing reinforcing ribs (26a). Assembly as set forth in one of the preceding claims, characterized in that it is further comprising a valve operator (32) disposed around a preferably cup-shaped base portion (22) of the stem (16) to assist the drainage of liquid from the vessel (4). Assembly as set forth in claim 15 characterized in that the valve operator (32) is cup-shaped to accumulate draining liquid to thereby maintain a constant liquid head and controlled flow resistance. Assembly as set forth in claim 15 or claim 16 characterized in that the valve operator (32) comprises connecting means for snap-actingly connecting the valve operator (32) to the base portion (22) of the stem (16). Assembly as set forth in claim 15, 16 or 17, characterized in that the valve operator (32) comprises an axial liquid drainage passage (31). Assembly as set forth in claims 18 characterized in that the valve operator (32) further comprises a hose connection (30). Assembly as set forth in any of the claims 15 to 19, characterized in that the valve operator (32) further comprises inwardly directed radial projections (60) which retain and properly position the gasket (46). Assembly as set forth in claim 17 and, optionally, any one of the following claims, characterized in that the connecting means comprises an internal radial flange (48) having an internal opening (50) for receiving the stem (16). Assembly as set forth in claim 17 and, optionally, any one of the following claims, characterized in that the connecting means connects the valve operator (32) to the base portion (22) of the stem (16) before the stem (16) is connected to the body portion (8). Assembly as set forth in claim 17 and, optionally, any one of the following claims, characterized in that the connecting means comprises a radially inwardly directed retaining lip (56) formed on the valve operator (32) and arranged to ride over and snap underneath a peripheral skirt (26) of the base portion (22) of the stem (16). Assembly as set forth in claim 15 and, optionally, any one of the following claims, characterized in that the valve operator (32) comprises an outer peripheral surface having axially oriented gripping ribs (58). Assembly as set forth in claim 15 and, optionally, any one of the following claims, characterized in that the valve operator (32) comprises connecting means for permitting connection of the valve operator (32) to the base portion (28) of the stem (16) with the stem (16) already connected to the body portion (8). Assembly as set forth in claim 25, characterized in that the connecting means comprises a tab (64) formed on an inner wall of the valve operator (32) and a notch (70) formed in the base portion (22) of the stem (16), the tab (64) being captured in the notch (70) to lock the valve operator (32) onto the base portion (22) of the stem (16).

Inventors: BOUCHET JEAN YVES, FERTIL DANIEL, HERMAN PETER K, BOUCHET, JEAN YVES, FERTIL, DANIEL, HERMAN, PETER K.
Applicants: FLEETGUARD INC, FLEETGUARD, INC.
Application year: 1990
Main classification: F16K51
IPC codes: F16F1, B01D36, F16K24, F02M37