Title of Invention

SHUTTLE VALVE

Abstract

The present invention provides an improved shuttle valve to supply a user with service water having a desirable pressure at normal time and supply the user with stored water in a water tank quickly and efficiently during a time of suspension of water supply. A shuttle valve that can be connected to a water supply piping system having a service water pipe connected to a water tank, a branch pipe extended from the service water pipe, a discharge pipe connected to the water tank and a supply pipe, comprises a casing having a discharge pipe connector at one end, a branch pipe connector at the other end and a supply pipe connector at a side, the discharge pipe connector connected to the discharge pipe, the branch pipe connector connected to the branch pipe, the supply pipe connector connected to the supply pipe and the casing having a hollow space therein, and a switching element inserted into the casing, the switching element having a shape of cylinder and having at least one longitudinal groove on an outer surface for water remained in the casing to move upward through the longitudinal groove.

Full Text

TECHNICAL FIELD The present invention relates to a shuttle valve that is operated by water pressure, and more specifically a shuttle valve installed in a water supply piping system of buildings such as an independent house, a tenement, an apartment or a business building in order to supply an user with service water effectively at normal time and supply an user with water stored in a water tank at the rooftop effectively during a time of suspension of water supply from the Waterworks Bureau. BACKGROUND ART The present invention is about an improved shuttle valve that can supply an user with service water provided by the Waterworks Bureau and stored water in the water tank more efficiently than the shuttle valve of the related art. A water tank is usually installed at the rooftop of residential buildings such as an independent house, tenement and apartment or business buildings. The service water provided by the Waterworks Bureau with a high water pressure is usually stored in the water tank and then supplied to the user. However, the high pressure of the service water becomes decreased almost to zero in a process of storage in the water tank before being supplied to the user. Therefore the stored water can be supplied to the user only by the pressure of the water contained in the water tank so that the stored water cannot be efficiently supplied to the user living on the high floors owing to a low water pressure. Though a booster pump can be additionally used to increase the water pressure, the use of the booster pump is disadvantageous in that it is very noisy and has high power consumption. To overcome above-mentioned problems, the applicant has filed an utility model, having an application number of ,20-2002-0025270Mand a title of "shuttle valve operated by water pressure" on 24 August, 2002. Hereinafter, a structure and a problem of the above utility model embodied to the present invention will be described with reference to figures attached. FIG. 1 illustrates an example of an installation of a shuttle valve in a water supply piping system of a building according to the present invention, FIG. 2 illustrates an exploded perspective view of a shuttle valve according to the related art and FIG. 3 illustrates a cross-sectional view of the shuttle valve in FIG. 2. Though the FIG. 1 is originally for an explanation of the present invention, it can be shared for an explanation of the shuttle valve according to the related art. The shuttle valve 50 according to the related art mainly comprises a casing 5, upper and lower caps 15 screwed to the casing 5 and a switching element 10 inserted into the casing 5. The upper and lower caps 15 are connected to a discharge pipe 220 and a branch pipe 230, respectively and a supply pipe connector 4 formed at a side of the casing 5 is connected to a supply pipe 240. The switching element 10 mainly comprises a body 6, a rubber packing 7, a washer 8 and a connecting bolt 9. The rubber packings 7 are connected to top and bottom surfaces of the body 6 by the connecting bolt 9. The switching element 10 is inserted into the casing 5 having a hollow space therein and moves up and down by a water pressure to open and shut selectively the upper and lower caps 15. When the service water is normally supplied to a service water pipe 210, the service water is supplied to the lower cap 15 via the branch pipe 230 and then thrusts the switching element 10 resting at the bottom of the hollow space of the shuttle valve 50 by a water pressure. The switching element 10 moved upward by the water pressure eventually shuts a water passage of the upper cap 15 connected to the discharge pipe 220 of the water tank 200. Because the switching element 10 moved upward shuts the upper cap 15, the service water supplied to the lower cap 15 can flow to the supply pipe 240 via the supply pipe connector 4. Accordingly, the service water can finally be supplied to the user when the user opens a tap 245 connected to the supply pipe 240 without a pressure loss that is produced by the Waterworks Bureau. While the tap 245 is shut off, the high pressure of the service water continuously pushes the switching element 10 up to shut the water passage of the upper cap 15 and thus the service water supplied to the service water pipe 210 from the Waterworks Bureau is supplied to the water tank 200. Once a certain amount of water is filled in the water tank 200, a float in the water tank 200 stops the service water from being supplied to the water tank. When the service water is not supplied to the service water pipe 210 from the Waterworks Bureau owing to a suspension of water supply, the stored water in the water tank 200 can be used. Once the user opens the tap 245 to use the water, the switching element 10 shutting the water passage of the upper cap 15 moves downward by a water pressure of the stored water in the water tank 200. The switching element 10 moved downward shuts the water passage of the lower cap 15 connected to the branch pipe 230 and thus the stored water in the water tank 200 can be supplied to the supply pipe 240 via the discharge pipe 220 connected to the water tank 200 for the user to use the water through the tap 245. However, even when the supply of the service water is suspended, a certain amount of residual water usually remains in the casing 5 of the shuttle valve 50. Because the water is a kind of incompressible liquid, the switching element 10 meets with resistance of the residual water in the casing 5 during a downward movement. That is, once the bottom of the switching element 10 touches the residual water while moving downward by the water pressure of the stored water in the water tank 200, the switching element 10 cannot move freely down to the water passage of the supply pipe 240. Because there exists a very small clearance between the switching element 10 and an inner surface of the casing 5 and the residual water flows upward through the clearance very slowly, the switching element 10 moves down very slowly. The user has to wait for a long time after the user opens the tap 245 to use the water because it takes time for the switching element 10 to move down and open the water passage of the supply pipe connector 4. It is experimentally verified that it takes about 4 to 5 minutes for the stored water in the water tank 200 flows out of the tap 245 after an opening of the tap 245. Therefore, the user is up to an inconvenience owing to the long time required for the stored water to come out of the tap 245. BRIEF DESCRIPTION OF DRAWINGS The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. 1 illustrates an example of an installation of a shuttle valve to a water supply piping system of a building according to the present invention; FIG. 2 illustrates an exploded perspective view of a shuttle valve according to the related art; FIG. 3 illustrates a cross-sectional view of the shuttle valve in FIG. 2; FIG. 4 illustrates a perspective view of a shuttle valve according to the present invention; FIG. 5 illustrates a cross-sectional view of the shuttle valve taken along a line "Vl-Vr of FIG. 4 according to a first embodiment of the present invention ; FIG. 6 illustrates a perspective view of a switching element inserted into the shuttle valve in FIG. 5; FIG. 7 illustrates modifications of the switching element in FIG. 6 ; FIG. 8 illustrates an exploded perspective view of a shuttle valve according to a second embodiment of the present invention ; FIG. 9 illustrates an exploded perspective view of a shuttle valve according to a third embodiment of the present invention ; FIG. 10 illustrates an exploded perspective view of a switching element inserted into a shuttle valve according to a fourth embodiment of the present invention ; and FIGs. 11 to 12 illustrate the shuttle valve according to the fourth embodiment of the present invention. TECHNICAL PROBLEM Accordingly, the present invention has been made keeping in mind the above problems occurring in the related art, and an object of the present invention is to provide an improved shuttle valve that can be easily installed in a water supply piping systems of residential buildings such as an independent house, a tenement and an apartment house or business buildings to supply service water to a user with a desired pressure and amount at a usual time and to supply stored water in a water tank quickly to the user at a time of a suspension of water supply. TECHNICAL SOLUTION To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a shuttle valve that can be connected to a water supply piping system having a service water pipe connected to a water tank, a branch pipe extended from the service water pipe, a discharge pipe connected to the water tank and a supply pipe, comprises a casing having a discharge pipe connector at one end, a branch pipe connector at the other end and a supply pipe connector at a side, the discharge pipe connector connected to the discharge pipe, the branch pipe connector connected to the branch pipe, the supply pipe connector connected to the supply pipe and the casing having a hollow space therein, and a switching element inserted into the casing, the switching element having a shape of cylinder and having at least one longitudinal groove on an outer surface. In the above, the switching element may have rubber packings on top and bottom surfaces, respectively. The switching element may have at least one circumferential groove on an outer surface. In the above, the switching element may further have a spring, a spring insertion hole and a spring fixing ring, the spring insertion hole formed in the switching element, the spring fixing ring inserted and fixed to one of the discharge pipe connector and the branch pipe connector and one end of the spring connected to the spring fixing ring and the other end of the spring disposed in the spring insertion hole. The switching element may have packing materials on top and bottom surfaces and the packing material may be formed one of rubber and urethane. In another aspect, a shuttle valve that can be connected to a water supply piping system having a service water pipe connected to a water tank, a branch pipe extended from the service water pipe, a discharge pipe connected to the water tank and a supply pipe, comprises a casing having a discharge pipe connector at one end, a branch pipe connector at the other end and a supply pipe connector at a side, the discharge pipe connector connected to the discharge pipe, the branch pipe connector connected to the branch pipe, the supply pipe connector connected to the supply pipe and the casing having a hollow space therein and having at least one longitudinal groove on an inner surface, and a switching element inserted into the casing to open and shut the discharge pipe connector and the branch pipe connector selectively by a water pressure. In the above, the switching element may further have a spring, a spring insertion hole and a spring fixing ring, the spring insertion hole formed in the switching element, the spring fixing ring inserted and fixed to one of the discharge pipe connector and the branch pipe connector and one end of the spring connected to the spring fixing ring and the other end of the spring disposed in the spring insertion hole. The switching element may have packing materials on top and bottom surfaces and the packing material may be formed one of rubber and urethane. In the above, a shape of the switching element may be selected from a sphere and a cylinder. The switching element may have rubber packings on top and bottom surfaces, respectively. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. ADVANTAGEOUS EFFECT According to the present invention, service water provided by the Waterworks Bureau with a high pressure can be supplied to an user at normal time and stored water in a water tank can be quickly supplied to the user by forming grooves on an outer surface of a switching element of a shuttle valve or on an inner surface of a casing of the shuttle valve for the water remained in the casing to flow upward along the grooves. Because the shuttle valve of the present invention has a simple structure, the shuttle valve of the present invention can easily be installed in a water supply piping system of buildings and is free of a frequent break down. In addition, because the shuttle valve of the present invention does not need a supply of power, it is economical, silent and environmental-friendly. Besides, the shuttle valve of the present invention can be installed in and removed from the water supply piping system of buildings, it can be widely applied to buildings such as an independent house, a tenement, an apartment and a business building. BEST MODE Reference will now be made in detail to the preferred embodiment of the present invention, which is illustrated in the accompanying drawings. FIG. 4 illustrates a perspective view of a shuttle valve according to the present invention, FIG. 5 illustrates a cross-sectional view of the shuttle valve taken along a line "VI-VI" of FIG. 4 according to a first embodiment of the present invention and FIG. 6 illustrates a perspective view of a switching element inserted into the shuttle valve in FIG. 5. Hereinafter, a structure and an operating principle will be described in detail with reference to FIG. 1 and FIGs. 4 to 6. The shuttle valve 100 according to the first embodiment of the present invention mainly comprises a casing 110 and a switching element 150 inserted into the casing 110 to move up and down in the casing 110. The casing 110 has a discharge pipe connector 120 at one end and a branch pipe connector 130 at the other end. The discharge pipe connector 120 is to be connected to a discharge pipe 220 connected to a water tank 200 and the branch pipe connector 130 is to be connected to the branch pipe 230 extended from a service water pipe 210. The casing 110 has a supply pipe connector 140 at a side to be connected to a supply pipe 240 connected to on-off valves such as a tap or a shower. The discharge pipe connector 120, the branch pipe connector 130 and the supply pipe connector 140 may have female screws in their inner surface to be connected to the discharge pipe 220, the branch pipe 230 and the supply pipe 240, respectively. The casing 110 has a hollow space therein for the switching element 150 to move up and down by a water pressure of the service water or stored water in the water tank 200. Stoppers 112 are formed on an inner surface of the casing 110 as shown in FIG. 5 to stop the movement of the switching element 150 in the casing 110. The switching element 150 can move up and down by the pressure of the water in order to supply an user with the water by opening and shutting water passage of the discharge pipe connector 120 and the branch pipe connector 130, selectively. The switching element 150 may desirably comprises a main body 152, rubber packings 156 connected to top and bottom surfaces of the main body 152 and a connecting element 158 to connect the rubber packings 156 to the main body 152. The connecting element 158 may further include washers (not shown). As shown in FIG. 6, the switching element 150 may have a shape of a cylinder and have a plurality of longitudinal grooves 154 on an outer surface thereof. The longitudinal grooves 154 are for drawing up water remained in the casing 110 during a time of suspension of water supply and more details will be explained later in the specification. The operating principle of the shuttle valve of the present invention is as follows. The service water transmitted by the Waterworks Bureau with a high pressure is supplied to the service water pipe 210 and then to the branch pipe 230. Because the service water supplied to the branch pipe 230 has a relatively high pressure, the water pressure of the service water pushes up the switching element 150 resting at the bottom of the casing 110. The switching element 150 moves up until it meets with the stopper 112 and thus shuts the water passage of the discharge pipe connector 120. The water pressure of stored water in the water tank 200 acts vertically on the top surface of the switching element 150 and the water pressure of the service water in the branch pipe connector 130 acts vertically on the bottom surface of the switching element 150. Because the water pressure of the service water is usually much higher than the water pressure of the stored water in the water tank 200, the pressure difference of the water keeps the switching element 150 shut the water passage of the discharge pipe connector 120 as shown in A of FIG. 5. While the switching element 150 is in contact with the stopper 112 to shut the water passage of the discharge pipe connector 120, water passage of the supply pipe connector 140 formed at the side of the casing 110 opens. Accordingly, the service water supplied to the branch pipe 230 can be supplied to the supply pipe 240 via the supply pipe connector 140 so that the service water can be finally supplied to the user by turning on the tap 245 connected to the supply pipe 240. As mentioned hereto, the service water provided by the Waterworks Bureau with a high pressure can directly and efficiently be supplied to the user without a loss of the pressure. While the user does not use the water by turning on the tap 245, the service water cannot flow to the supply pipe 240 via the branch pipe 230. Accordingly, the switching element 150 keep shutting the water passage of the discharge pipe connector 120 so that the service water supplied to the service water pipe 210 flows up to the water tank 200 to fill the water tank 200 to a certain amount. When the service water may not be supplied to the service water pipe 210 from the Waterworks Bureau in cases such as a suspension of water supply, the stored water in the water tank 200 can be used instead of the service water. Because the water pressure of the stored water acting on the top surface of the switching element 150 becomes higher than the pressure acting on the bottom surface of the switching element 150, the switching element 150 starts to move down. By the way, even when the service water is not supplied to the branch pipe connector 130, there remains a certain amount of water in the casing 110. Accordingly, the switching element 150 undergoes a resistance of the remained water during the down movement to let the stored water flow to the supply pipe connector 140. However, because at least one longitudinal grooves 154 is formed on an outer surface of the switching element 150 according to the present invention, the remained water can flow up along the longitudinal grooves 154 while the switching element 150 moves down. As a result, the switching element 150 can quickly and efficiently shut water passage of the branch pipe connector 130 leaving the water passage of the supply pipe connector 140 open. Once the switching element 150 shuts the water passage of the branch pipe connector 130, the stored water in the water tank 200 can flow into the casing 110 and then to the supply pipe 240. As mentioned above, the stored water of the water tank 200 can be supplied to the user more quickly and efficiently than the related art. FIG. 7 illustrates modifications of the switching element in FIG. 6. The switching element 150 may have circumferential grooves 154a and 154b on an outer surface of the main body 152 as well as the longitudinal groove 154. The circumferential grooves 154a and 154b is to shorten a length of a flowing path of the remained water flowing along the longitudinal groove 154. That is, the circumferential grooves 154a and 154b let the remained water flowing along the longitudinal groove 154 be discharged to the supply pipe connector 140 more quickly so that the switching element 150 can move down to stand at the stopper 112 more quickly. Shapes of the grooves 154,154a and 154b can be diversely modified on condition that the modified shape can fulfill the same function as mentioned above. MODE FOR INVENTION Other embodiments of the present invention will be descried in detail hereinafter with reference to the figures attached. FIG. 8 illustrates an exploded perspective view of a shuttle valve according to a second embodiment of the present invention. In the second embodiment of the present invention, a longitudinal groove 114 is formed on an inner surface of the casing 110 instead of on the outer surface of the switching element 160 to reduce the resistance of the water remained in the casing 110. Accordingly, the remained water in the casing 110 can flow along the longitudinal groove 114 formed on the inner surface of the casing 110 while the switching element 160 moves down. The switching element 160 of the second embodiment has almost same structure as that of the first embodiment except that it does not have the longitudinal groove 154 on the outer surface. It is desirable that the number of the longitudinal groove 114 on the inner surface of the casing be more than one. Except above-mentioned characteristics of the second embodiment, a basic structure and an operating principle are almost same as that of the first embodiment. FIG. 9 illustrates an exploded perspective view of a shuttle valve according to a third embodiment of the present invention. In the third embodiment of the present invention, a switching element 170 has a shape of a sphere unlike the previous embodiments. At least one longitudinal groove 114 is formed on the inner surface of the casing 110. Except above-mentioned characteristics of the third embodiment, a basic structure and an operating principle are almost same as those of the previous embodiments. FIG. 10 illustrates an exploded perspective view of a switching element inserted into a shuttle valve according to a fourth embodiment of the present invention and FIGs. 11 to 12 illustrate the shuttle valve according to the fourth embodiment of the present invention. As shown in the figures, the switching element 180 of the fourth embodiment has a main body 182, a spring 195 and a spring fixing ring 190. A spring insertion hole 187 having a shape of a cylinder is formed in the main body 182. One end of the spring 195 is connected to the spring fixing ring 190 and the other end of the spring 195 is disposed in the spring insertion hole 187. At least one longitudinal groove 154 is formed on an outer surface of the main body 182. Protrusions 184 and 186 are formed on top and bottom surface of the main body 182 to connect packing materials 189 and 188 to the main body 182. The packing materials 188 and 189 may desirable be formed one of rubber and urethane. One of the top and bottom surfaces of the main body 182 is open for the spring to be inserted. That is, as shown in FIG. 10, the spring insertion hole 187 having a certain depth from the top surface of the main body 182 is formed in the main body 182 and a portion of the spring 195 is inserted into the spring insertion hole 187. One end of the spring 195 is connected to the spring fixing ring 190 and the other end of the spring 195 may be connected to a bottom surface of the spring insertion hole 187. The spring fixing ring 190 can be put into one of the discharge pipe connector 120 and the branch pipe connector 130 along the screws formed on inner surfaces of the discharge pipe connector 120 and the branch pipe connector 130. FIG. 11 illustrates the structure of the shuttle valve when the spring fixing ring 190 is fixed to the discharge pipe connector 120 and FIG. 12 illustrates the structure of the shuttle valve when the spring fixing ring 190 is fixed to the branch pipe connector 130. The spring 195 is a compressive spring for FIG. 11 and a tensile spring for FIG. 12. An operation principle of the fourth embodiment of the present invention will be explained in detail hereinafter with reference to FIG. 11. The service water transmitted by the Waterworks Bureau at a high pressure flows into the casing 110 via the branch pipe 230 and the service water pushes the main body 182 upward. The spring 195 is a compressive spring as mentioned before and an elastic constant of the spring 195 must not be too high considering the water pressure of the service water. The moving main body 182 stops its movement by the stopper 112 and then shut the water passage of the discharge pipe connector 120. The packing material 189 is for shutting the water passage of the discharge pipe connector 120 more securely and it desirably be formed of a material having a good sealing property such as rubber and urethane. Once the main body 182 moves upward and meets with the stopper 112 to shut the water passage of the discharge pipe connector 120, the water passage of the supply pipe connector 140 opens so that the service water in the branch pipe 230 can flow to the supply pipe 240 via the supply pipe connector 140. When the service water is not provided to the service water pipe 210, the main body 182 starts to move down by the combined pressure of the stored water in the water tank 200 and the spring. While the main body 182 moves down, the remained water in the casing 110 flows along the longitudinal groove 154 formed on the outer surface of the main body 182 so that the main body 182 of the switching element 180 can move down more quickly. In the present embodiment, because the main body 182 moves down by a spring force as well as the water pressure of the stored water in the water tank 200, the main body 182 can move down much faster than the previous embodiments. The main body 182 moving down stops its movement when it meets with the stopper 112 to shut the water passage of the branch pipe connector 130. Accordingly, the stored water of the water tank 200 can be supplied to the supply pipe 240 via the discharge pipe connector 120. In FIG. 12, the spring fixing ring 190 is put into the branch pipe connector 130 and the spring insertion hole 187 is formed from the bottom surface of the main body 182 to an inner side of the main body 182. The spring 195 here is the tensile spring as mentioned before. Though in the fourth embodiment, the longitudinal groove 154 is formed on the outer surface of the main body 182 for an example, the longitudinal groove may be formed on the inner surface of the casing 110 as in the second embodiment of the present invention. Though the technical idea of the present invention has been explained with a case in which the shuttle valve 100 is vertically installed in the water supply piping system, the shuttle valve 100 may be horizontally installed in the water supply piping system depending on the situation. It will be apparent to those skilled in the art that various modifications and variations can be made in the shuttle valve without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. CLAIMS 1. A shuttle valve that can be connected to a water supply piping system having a service water pipe connected to a water tank, a branch pipe extended from the service water pipe, a discharge pipe connected to the water tank and a supply pipe, comprising: a casing having a discharge pipe connector at one end, a branch pipe connector at the other end and a supply pipe connector at a side, the discharge pipe connector connected to the discharge pipe, the branch pipe connector connected to the branch pipe, the supply pipe connector connected to the supply pipe and the casing having a hollow space therein ; and a switching element inserted into the casing, the switching element having a shape of cylinder and having at least one longitudinal groove on an outer surface. 2. The shuttle valve according to claim 1, wherein the switching element has rubber packings on top and bottom surfaces, respectively. 3. The shuttle valve according to claim 1, wherein the switching element has at least one circumferential groove on an outer surface. 4. The shuttle valve according to claim 1, wherein the switching element further has a spring, a spring insertion hole and a spring fixing ring, the spring insertion hole formed in the switching element, the spring fixing ring inserted and fixed to one of the discharge pipe connector and the branch pipe connector and one end of the spring connected to the spring fixing ring and the other end of the spring disposed in the spring insertion hole. 5. The shuttle valve according to claim 4, wherein the switching element has packing materials on top and bottom surfaces. 6. The shuttle valve according to claim 5, wherein the packing material is formed one of rubber and urethane. 7. A shuttle valve that can be connected to a water supply piping system having a service water pipe connected to a water tank, a branch pipe extended from the service water pipe, a discharge pipe connected to the water tank and a supply pipe, comprising: a casing having a discharge pipe connector at one end, a branch pipe connector at the other end and a supply pipe connector at a side, the discharge pipe connector connected to the discharge pipe, the branch pipe connector connected to the branch pipe, the supply pipe connector connected to the supply pipe and the casing having a hollow space therein and having at least one longitudinal groove on an inner surface ; and a switching element inserted into the casing to open and shut the discharge pipe connector and the branch pipe connector selectively by a water pressure. 8. The shuttle valve according to claim 7, wherein the switching element further has a spring, a spring insertion hole and a spring fixing ring, the spring insertion hole formed in the switching element, the spring fixing ring inserted and fixed to one of the discharge pipe connector and the branch pipe connector and one end of the spring connected to the spring fixing ring and the other end of the spring disposed in the spring insertion hole. 9. The shuttle valve according to claim 8, wherein the switching element has packing materials on top and bottom surfaces. 10. The shuttle valve according to claim 9, wherein the packing material is formed one of rubber and urethane. 11. The shuttle valve according to claim 7, wherein a shape of the switching element is selected from a sphere and a cylinder. 12. The shuttle valve according to claim 7, wherein the switching element has rubber packings on top and bottom surfaces, respectively. 13. The Shuttle Valve substantially as herein described with reference to the accompanying drawings.

Documents:

2577-chenp-2005 abstract granted.pdf

2577-chenp-2005 claims granted.pdf

2577-chenp-2005 description (complete) granted.pdf

2577-chenp-2005 drawings granted.pdf

2577-chenp-2005-abstract.pdf

2577-chenp-2005-claims.pdf

2577-chenp-2005-correspondnece-others.pdf

2577-chenp-2005-correspondnece-po.pdf

2577-chenp-2005-description(complete).pdf

2577-chenp-2005-drawings.pdf

2577-chenp-2005-form 1.pdf

2577-chenp-2005-form 18.pdf

2577-chenp-2005-form 26.pdf

2577-chenp-2005-form 3.pdf

2577-chenp-2005-pct.pdf