IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0328606
(1981-12-08)
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발명자
/ 주소 |
- Roger Harry (124 Banks Ave. Lafayette LA 70506)
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인용정보 |
피인용 횟수 :
6 인용 특허 :
3 |
초록
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A pilot valve is disclosed having a piston actuating a valve element shiftable between a first and second positions. The piston is comprised of two concentrically arranged pistons, the larger piston having an internal bore with two sections of staggered diameters and a smaller, correspondingly shape
A pilot valve is disclosed having a piston actuating a valve element shiftable between a first and second positions. The piston is comprised of two concentrically arranged pistons, the larger piston having an internal bore with two sections of staggered diameters and a smaller, correspondingly shaped second piston inserted in the concentric internal bore. A single O-ring on the bottom of the second section of the first piston annularly mounted around the second section of the second piston seals the piston chamber from a fluctuating sensed fluid pressure. The first piston has a longer upper bore section than the second piston. A spacer is placed at the juncture of the first and second sections of second piston so as to enable the first and second piston to act in unison in actuating the valve element. In this mode, the effective surface area of the piston is equal to the diameter of the larger piston or of the O-ring. When the spacer is removed, the second piston is enabled to act independently of the first piston. Therefore, the effective surface area of the piston in this mode is equal to the cross sectional area of the second piston only and the pressure required to influence the position the valve element opposed by a single spring is increased. Thus two discrete ranges are enabled for the pilot valve as herein disclosed determined by the presence or absence of the spacer.
대표청구항
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A pilot valve comprising: (a) a valve body, having: (1) an elongated bore therein, (2) a first fluid inlet port communicating with said said bore, (3) a second fluid inlet port communicating with said bore, (4) an outlet port communicating with said bore, and (5) a sensing port communicating with sa
A pilot valve comprising: (a) a valve body, having: (1) an elongated bore therein, (2) a first fluid inlet port communicating with said said bore, (3) a second fluid inlet port communicating with said bore, (4) an outlet port communicating with said bore, and (5) a sensing port communicating with said bore; (b) a valve element slidably engaged within said bore for regulating the flow of fluid through said pilot valve, said valve element being shiftable between (1) a first position permitting communication between said first inlet port and said outlet port and precluding communication between said second inlet port and said outlet port; and (2) a second position permitting communication between said second inlet port and said outlet port and precluding communication between said first inlet port and said outlet port; (c) means for urging said valve element into its first position, the improvement comprising: a piston means slidable within a piston chamber for shifting said valve element from its first position to its second position, said piston means being exposed to said sensing port so that sufficient fluid pressure applied to said sensing port will cause said piston means to engage said valve element to shift said element from its first position to its second position, against the action of said urging means, said piston means comprising: (a) a first piston slidable within said piston chamber, said first piston having a first and second sections, said first section being of larger diameter and concentrically aligned with said second section, and having a concentric bore therethrough, said concentric bore being of first and second sections, said sections being aligned with the first and second sections of said first piston, said first section of said concentric bore being of larger diameter than the second section of the concentric bore, and (b) a second piston slidably mounted within said first piston, said second piston having first and second sections, said first section of said second piston being of larger diameter than said second section and slidably in contact with the first section of said concentric bore of said first piston, the length said first section of said second piston being less than that of said first section of said concentric bore, and said second section of said second piston being slidably in contact with the second section of said concentric bore; (c) seal means annularly mounted around said second section of said second piston and having an outer diameter substantially the same as that of the second section of said first piston so as to hermetically seal said sensing port from the elongated bore, said seal means being capable of sliding movement within said piston chamber in response to the fluctuating fluid pressure within said sensing port and in response to movement by said first piston. (d) spacer means for positioning said second piston within said first piston, said spacer means being placed at the juncture of the first and second sections of said second piston, said spacer being of substantially the same thickness as the difference in lengths between the first section of said second piston and the first section of the concentric bore of said first piston, wherein said piston means defines first and second operating modes, (a) said first operating mode wherein said spacer is positioned between said first and second piston means so as to mount said second piston flush with the ends of said first piston whereby the effective surface area of the piston means is equal to that area defined by the diameter of said seal means, (b) said second operating mode wherein said spacer is removed from between said first and second pistons whereby the larger surface area of said first piston and said seal means will enable the fluctuating fluid pressure within said sensing port will induce said first piston and seal means into contact with said valve body at a relatively low level of pressure with respect to that level of pressure required to move said second piston upward into contact with said valve element in opposition to said means for urging said valve element into its first position and wherein the effective surface area of said piston means is reduced to that of the second end of said second piston, the presence or absence of said spacer means determines the range within in which said piston means is enabled to shift said valve element from said first position to said second position.
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