Limit valve with overtravel detector

• US 3,921,665 A
• Filed: 12/17/1974
• Issued: 11/25/1975
• Est. Priority Date: 12/17/1974
• Status: Expired due to Term

• Current Assignee: Joseph Lebzelter
• Original Assignee: Joseph Lebzelter
• Inventors: Lebzelter, Joseph
• Primary Examiner(s): Klinksiek, Henry T.
• Application Number:
  US05/533,561
• Time in Patent Office: 343 Days
• Field of Search: 91/37 251/3,85,277,278,321 137/553,557,630.22
• US Class Current: 137/553
• CPC Class Codes: F16K 11/07 with cylindrical slides
• CPC Class Codes: F16K 37/0066 Hydraulic or pneumatic means F16K37/0075 takes precedence
• CPC Class Codes: Y10T 137/8225 Position or extent of motion indicator
• CPC Class Codes: Y10T 137/8326 Fluid pressure responsive indicator, recorder or alarm
• CPC Class Codes: Y10T 137/8704 First valve actuates second valve

Abstract

A fluid limit valve, comprising: a valve body having aligned valve bore and stem counterbore; transverse input and output fluid channels opening into the valve bore; a valve member slidable in the valve bore; and a spring-pressed, telescopic valve extension or stem slidable in the stem counterbore, is provided with means for producing a fluid signal in response to overtravel of the stem and valve member, comprising: a poppet valve counterbore aligned with the valve bore and containing a poppet valve including a cup-shaped poppet cylinder partially closed by a centrally-apertured poppet seat; a headed poppet loosely slidable in the cylinder and seat with a shank thereof extending toward but normally spaced from the valve member, a ring seal between the poppet and the seat, and a coil spring in the cylinder biasing the poppet toward the valve member and compressing the ring seal; fluid channels in the valve body and poppet cylinder wall connecting the interior of the cylinder with an input channel, for pressurizing the cylinder; and a fluid signal channel connected to the closed space between the valve member and the poppet valve; whereby excessive movement of the stem and valve member in overtravel beyond the normal operating stroke of the valve causes the valve member to engage and move the poppet, thereby opening the fluid seal and admitting fluid from the poppet cylinder to the space and fluid signal channel. The stem spring is weaker than the poppet spring, to permit a predetermined amount of overtravel before the poppet valve is opened and the fluid signal is produced. The invention is disclosed as applied to both double and single land valves.

Claims

1. In combination:

a fluid valve including a movable valve member having a normal safe operating path and an unsafe overtravel path;

a normally-closed poppet valve comprising a poppet guide and a spring-pressed poppet slidable in said guide and positioned to be engaged and moved by said valve member in its overtravel path to open said poppet valve;

means for applying fluid pressure to the interior of said guide; and

means, responsive to the release of said fluid from said guide when said poppet valve is opened by said valve member, for producing a fluid signal indicating the overtravel motion of said valve member.

2. The combination of:

a fluid valve including a valve body and valve member slidable in said valve body, said valve member having a normal safe operating path and an unsafe overtravel path which may damage said valve;

with means for detecting the movement of said valve member in said overtravel path, comprising;

a poppet valve including a poppet guide, containing a poppet and a spring, mounted adjacent to said valve member with said poppet loosely sliding in said guide and positioned in the path of said valve member;

fluid sealing means between said poppet and said guide operative prior to movement of said poppet by said valve member;

means for applying fluid pressure to the interior of said guide;

means forming a chamber between said poppet guide and said valve member; and

means communicating with said chamber for deriving a fluid pressure signal therefrom;

said valve and said poppet being so constructed and arranged that said valve member contacts said poppet at the end of its normal operating path, and when said valve member is moved along said overtravel path it moves said poppet against said poppet spring and opens said sealing means, thereby admitting fluid from said guide to said chamber and producing said fluid signal.

3. The combination as in claim 2, wherein said means for applying fluid pressure is a fluid channel connecting said poppet guide with said fluid valve.

4. The combination as in claim 2, wherein:

said valve includes a valve stem connected to said valve member by a resilient telescopic connection, and adapted to be externally actuated to operate said fluid valve;

said valve stem has a safe overtravel path between said operating path and said unsafe overtravel path; and

the relative strengths of said poppet spring and said resilient connection are such that, during said safe overtravel path of said stem beyond said operating path, said connection is telescoped to prevent movement of said poppet and production of said fluid signal.

5. A fluid limit valve system comprising:

a valve body having a main bore, and at least two fluid control channels communicating with said main bore;

a valve member including a land slidable in said main bore for cooperation with said channels;

a valve stem connected to said valve member and extending outwardly from said body for external actuation thereof;

means for limiting the outward extension of said stem;

means biasing said valve member toward said valve stem;

A poppet guide, containing a poppet and a spring, mounted in said body with said poppet loosely sliding in said guide and extending into said main bore for coaction with said valve member;

fluid sealing means between said poppet and said guide operative prior to movement of said poppet by said valve member;

an additional fluid channel in said body connecting one of said control channels with the interior of said poppet guide;

a fluid signal channel in said body communicating with the space between said valve member and said poppet guide;

said control channels and said valve member being so constructed and arranged that, when moved a given distance by said stem in its normal operating stroke, said valve member connects two of said control channels together and then contacts said poppet, and on overtravel of said stem, said valve member moves said poppet against said poppet spring and opens said sealing means, thereby admitting fluid from said guide to said space and producing a fluid signal at said signal channel.

6. A valve system as in claim 5, wherein said valve member is connected to said stem by a resilient telescopic connection;

the relative strengths of said poppet spring and said resilient connection being such that, on initial overtravel of said stem, said connection is telescoped to prevent movement of said poppet and production of said fluid signal.

7. A valve system as in claim 5, comprising a spool-shaped valve member and three control channels, one input, one output and one vent;

the vent channel being connected to the output channel prior to actuation of said valve stem; and

the input channel being connected to the output channel by said operating stroke.

8. A fluid limit valve structure comprising:

a valve body having axially-aligned stem, valve and poppet guide bores, a fluid signal channel, and at least two fluid control channels communicating with said control valve bore;

valve means including a valve member comprising at least one land slidable in said valve bore for cooperation with said control channels, and a headed valve plunger abutting said valve member and extending into said stem bore;

a valve stem in said stem bore and extending outwardly from said body for external actuation thereof and comprising an axial plunger bore in which said plunger head is slidable, a plunger spring interposed between said plunger head and the base of said plunger bore, and a head on said stem slidable in said stem bore;

retaining means in said stem bore limiting the outward extension of said stem;

a cup-shaped poppet guide mounted in said poppet guide bore with its open end adjacent to said valve bore;

said guide and said valve body being formed with an additional channel connecting the interior of said guide with one of said control channels;

a poppet loosely slidable in said guide;

a poppet spring in said guide biasing said poppet to extend initially into said valve bore for coaction with said valve member;

a fluid seal between said poppet and said guide, operative when said poppet is in its initial extended position; and

a valve spring in said valve bore in the space between said land and said poppet guide;

said signal channel communicating with said space;

said control channels and said valve member being so constructed and arranged that, when moved a given distance in said body by said stem in its operating stroke, said valve member connects said control channels together and then contacts said poppet;

the relative strengths of said springs, and the fluid pressure in said poppet guide, being such that, on initial overtravel of said stem, said stem compresses said plunger spring without moving said poppet, and on further overtravel, said stem and said valve member compress said poppet and valve springs and move said poppet, thereby opening said fluid seal to allow fluid to flow from said guide into said space, producing a fluid signal at said signal bore.

9. A valve structure as In claim 8, wherein a central portion of said valve member extends beyond said land and into said space.

10. A valve structure as in claim 8, wherein said valve member includes two spaced lands which cooperate with three control channels to produce two separate fluid paths through said valve, one being a vent path existing prior to actuation of said stem and the other being a control path established by said operating stroke.