US2925242A

US2925242A - Throttle valve having flow passages for minimizing drift

Info

Publication number: US2925242A
Application number: US350996A
Authority: US
Inventors: Noon T Cyril; Walter R Chapman
Original assignee: Thompson Ramo Wooldridge Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1949-04-27
Filing date: 1953-04-24
Publication date: 1960-02-16
Anticipated expiration: 1977-02-16

Description

Feb. 16, 1960 T c. NOON ETAL THROTTLE VALVE HAVING FLOW PASSAGES FOR MINIMIZING DRIFT Original Filed April 27. 1949 I f, A/

` THROTI'LE VALVE HAVING FLOW PASSAGES FOR MINIMIZING DRIFT T' Cyril Noon, Bainbridge Township, Geauga County, and Walter R. Chapman, Bedford, Ohio, assignors to Original application April 27, 1949, Serial No. 89,884, now Patent No. 2,707,866, dated May 10, 1955. Di-

vided and this application April 24, 1953, Serial No. l

The subject matter of this disclosure constitutes a division of our copending application Serial No. 89,884, i

led April 27, 1949, issued as United States Patent No.

v The present invention relates generally to a fuel control unit to be used in conjunction with an electronic uid control circuit of the type disclosed in the copending applications of Oiner Serial Nos. 13,546, now United States Patent 2,573,596, and 770,872.

This disclosure emphasizes features of the throttle valve incorporated in the fuel control unit.

An object of the present invention is to provide an improved balanced throttle valve wherein liow through the valve is controlled by positioning a balanced floating piston.

Many other features, advantages and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description which follows and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention are shown by way of illustrative example.

Figure l is a view in elevation, partly in section, of the throttle unit;

Figure 2 is a view in elevation partly in section of the throttle unit-of the invention.

For an understanding of the environment in which the throttle valve 19 of the invention may be utilized reference is made to applicants parent Patent No. 2,707,866, issued May, 10, 1955. The throttle valve 19 comprises a valve body having a cylindrical bore closed by end plates 117, and is provided with a port 39 communicating with the upper end of the throttle valve and a port 43 communicating with the lower end thereof as hereinafter described.

The function of the throttle valve 19 is to meter flow to a nozzle or the like. It is composed of a freeoating hydraulically balanced piston 105 having upper and

lower lands

113 and 116 respectively controlling

orifices

106 and 107 formed in a throttle valve sleeve 108. In Figure l, the fuel ows into an annular passage 110 suitably connected to a source of tiuid under pressure (not shown). From the annular passage 110 in the throttle valve body, the fuel iows through the metering port 106 into sleeve 108 and out through port 107 and thence out the outlet 112.

Referring to Figure l, the upper piston land 113 is provided with a groove 114 and a leakage path is formed by holes 115 to balance the pressure in the center zone between the upper piston land 113 and the lower piston land 116. In operation, the throttle valve is positioned by applying differential pressure into chambers 153 and 154. When the steady state condition exists, the differential pressure between the chambers 153 and 154 reduces to zero and it thus becomes important for the leakages across the upper and lower throttle valve piston lands t0 be equal. Unequal leakages across these lands change 'ice N the differential pressures in the chambers 153 and 154 llilgmpson Ramo Wooldridge Inc., a corporation of and cause the piston to move without having any signal from the servo system. t j j A j 1 Accordingly, the purpose and the advantages of groove 114 and holes 115 are to overcome such difficulties. The

groove 114 is an annular groove around `the periphery' holes 115 is to provide the same leakage across Veach land of the throttle valve piston. By having equalpleakages across the two lands of the throttle valve piston, minimum throttle valve piston drift is insured. The throttle housing 19 is provided with upper and lower closures 117 suitably affixed to the housing for assembling the piston and the sleeve 108. Upper and lower adjusting stops 118 and 119 are provided for limit,- ing piston 105 to a predetermined range of movement.

A starting solenoid 50 adaptedA to -push Vout when` energized, is mounted as illustrated in Figure 2, and provides a throttle stop during starting to prevent over-travel of the throttle valve piston. The solenoid 50 includes a winding 50a adapted to move a piston 50b outwardly when energized by the line 52 from the electronic control.

An idle solenoid 51 is also provided and forms an idle fuel ow stop for the throttle valve piston during normal operation. In Figure 2, the idle solenoid 51 is shown normally biased outwardly in the path of movement of the throttle valve piston 105. The solenoid 51 thus includes spring means 19 for biasing the piston 51b outwardly as described, retraction being afforded by the winding 51C to include the line 53 from which the electronic control is connected.

Referring to Figure 2, the throttle valve 19 is provided with

passages

120 and 121 connected to chambers formed above and below the upper piston land 122 and the lower piston land 116. These

passages

120 and 121 are connected to the ports 39 and 43.

In order to prevent a suction pull on the piston 105 by the local low static pressure which may be produced by increased velocity ow of huid through the port 106,

the piston is relieved as at a.

High pressure fuel or uid is allowed to ow upward by the metering land and into the upper throttle valve chamber 153 through the passage 120 closing the throttle valve. Fuel in the lower throttle chamber 154 is vented to the lower pressure port 148.

While we have resorted to detail in the description of our invention for the sake of clarity, it will, of course, be understood that many modifications `with respect to various details will suggest themselves to those versed in the art which will not mark a departure from the true spirit of our invention. We desire to incorporate within the scope of the patent warranted hereon all such modiications as reasonably and properly come within the scope of our contribution to the art.

We claim as our invention:

1. A throttle valve comprising a sleeve having an inlet port and an outlet port, a piston valve slidable in said sleeve to control the ow of uid through said ports and including a first land and a second land spaced longitudinally therefrom, said lands being of different longitudinal dimension wherein the longer of said lands will completely overlie one of said ports in one position of said piston, and passage means including an annular peripheral groove in said longer of said lands and interconnecting said inlet and outlet ports whenever said piston is in said one position, thereby to insure a ow passage between said ports and balancing pressure differentials therebetween. i

2; A throttle valve comprising a sleeve having an inlet portand an outlet port,` a piston valve slidable in said sleeve to control the :flow of uid through said ports and including a first landland a second land spaced lngitudinally therefrom, 'said'lands being of different longitudinaldmeusion wherein the longer 'of said lands will completely overlie one of said ports in one position of? ,said piston,k and' passage means including an annular peripheral'groovein said longer of said landsland interonnectingfsaidjnlet and outlet vports whenever said piston" -isin said one position, thereby to insure a ow passage between said ports and balancing pressure differentials therebetween, means on each of the opposite ends of` said"fpiston frming a motive-surface n a pressure Vcontrol chamber to hydraulically position said pistouv in. said' sleeve, a pair of longitudinally spaced openingsinsaid fsleeve at opposite ends of said piston, a' first solenoid operated 'stop' means including an adjustableprojectionextending through one of said spaced openings toprevent `overtravel of the piston, and a second-solenoidope'rated stop means including a second adjustable 'prectioneXend-ing through the other of said openings `insaid sleeve to-form a throttle stop at the other end of ysaid pis/ton.

lReferences Cited in the `lle of this patent Ik u UNITED STATES PATENTS Sewall June 10, 1890 Crowe July 19, 1904 Goodlett Mar. 13, 1906 Luna May 24,1910 Ledoux Aug. 8, 1811 Frost Man 30, 1926l Cordier .Man 31, '1931 McGuire .A\`1g.. 29,' 1933 Been Mar. 16,. 1937 Cox July 26, 1938 Jung Oct. '29,v 1.940' SeippelV Nov. 25,1941 Warren Dec..25 1945 Petry Mar. 1,'1949 Evans et al. July 18, 1950 Carey July 10, 1951 Coar Jan. 22,1952," i Beckett et al. Feb. 26, 1952 West et al May`6, 1952 Miller July 29, 1952' Maha Nov. 4/1952