1. A choke valve comprising:
a body having an axial through hole and a radial entry port;
a valve seat coaxially housed in the body axial through hole on a first side of said radial entry port;
a pressure balanced valving member axially reciprocable within the body axial through hole between a first sealing position bearing against said valve seat and a second position spaced away from said seat;
actuator means for applying reciprocatory motion to the pressure balanced valving member through an intermediate structure; and
a shearable mechanism interconnecting the actuator means and the valving member, wherein the shearable mechanism includes a stem and two split shear ring halves mounted in a mounting groove in the stem and retained therein by a retension device where the stem serves as the intermediate structure, wherein the shearable mechanism is responsive to fluid pressure in excess of a predetermined value.
2. The choke valve of claim 1, further comprising an antirotational device for preventing the valving member from rotating.
3. The choke valve of claim 2, wherein the antirotational device includes a stem and a shear pin connecting the stem to the actuator means.
4. The choke valve of claim 1, wherein the shearable mechanism includes a shear pin.
5. The choke valve of claim 1, wherein the actuator means is manually, electrically, hydraulically or pneumatically operated.
6. A choke valve comprising:
a body having an axial through hole passing from a first side of the body to a second side of the body, an outlet passageway coaxially aligned with the through hole and positioned at the first side of the body, and a radial inlet port intersecting the through hole between the first and second sides of the body;
a valve seat coaxially housed in the through hole between the inlet port and the outlet passageway;
a valving member axially reciprocable within the through hole between a first position bearing against the valve seat and a second open position spaced away from the valve seat;
an actuator attached to the second side of the body for reciprocably moving the valving member between the first position and the second position wherein the actuator includes an axially reciprocable actuator shank; and
a shearable mechanism having a stem interconnecting the actuator shank and the valving member and two split shear ring halves mounted in a mounting groove in the stem and retained therein by a retension device;
whereby whenever the shearable mechanism is subjected to fluid pressure in excess of a predetermined value from the outlet passageway the shearable mechanism will shear thereby allowing the release of backpressure.
7. The choke valve of claim 6, further comprising an antirotational device to prevent the rotation of the valving member.
8. The choke valve of claim 6, wherein at least one fluid channel traverses the valving member.
9. The choke valve of claim 6, wherein the shearable mechanism includes a shear pin connecting the stem to the actuator shank.
10. The choke valve of claim 9, wherein one end of the actuator shank has a socket, the socket receiving a first end of the stem.
11. The choke valve of claim 10, wherein the shear pin joins the first end of the stem to the actuator shank while the stem is positioned within the socket at less than the full length of the socket.
12. The choke valve of claim 6, wherein one end of the actuator shank has a socket, the socket receiving a first end of the stem.
13. The choke valve of claim 6, wherein the actuator is manually, electrically, hydraulically or pneumatically operated.
14. A choke valve comprising:
a body having an axial through hole passing from a first side of the body to a second side of the body, an outlet passageway coaxially aligned with the through hole and positioned at the first side of the body, and a radial inlet port intersecting the through hole between the first and second sides of the body;
a valve seat coaxially housed in the through hole between the inlet port and the outlet passageway;
a pressure balanced valving member axially reciprocable within the through hole between a first position bearing against the valve seat and a second open position spaced away from the valve seat;
an actuator attached to the second side of the body, the actuator having an axially reciprocating actuator shank for reciprocably moving the valving member between the first position and the second position;
an antirotational device preventing the valving member from rotating within the through hole; and
a shearable mechanism interconnecting the actuator shank and the valving member, the shearable mechanism comprising
a stem, a first end of the stem positioned in a socket in one end of the actuator shank and a second end of the stem mounted to the valving member,
a shear pin passing through the stem proximal to first end of the stem and passing through a wall of the socket in the actuator shank when the first end of the stem is located in the socket at less than a full depth of the socket; and
a pair of split shear ring halves mounted in a mounting groove in the stem proximal to the shear pin, and a shear ring keeper device mounted over the shear ring halves and the shear pin to maintain the shear ring halves and the shear pin in position;
whereby whenever the valving member is subjected to a fluid pressure in excess of a predetermined value from the outlet passageway the shear pin will shear and the stem will move further into the socket in the actuator shank thereby allowing the release of backpressure.
15. The choke valve of claim 14, wherein the valving member has at least one fluid channel traversing the valving member.
16. A choke valve comprising:
a body having an axial through hole passing from a first side of the body to a second side of the body, an outlet passageway coaxially aligned with the through hole and positioned at the first side of the body, and a radial inlet port intersecting the through hole between the first and second sides of the body;
a valve seat coaxially housed in the through hole between the inlet port and the outlet passageway;
a pressure balanced valving member axially reciprocable within the through hole between a first position bearing against the valve seat and a second open position spaced away from the valve seat;
an actuator attached to the second side of the body, the actuator having an axially reciprocating actuator shank for reciprocably moving the valving member between the first position and the second position;
an antirotational device preventing the valving member from rotating within the through hole; and
a shearable mechanism interconnecting the actuator shank and the valving member, the shearable mechanism comprising
a stem, a first end of the stem positioned in a socket in one end of the actuator shank at less than a full depth of the socket and a second end of the stem mounted to the valving member,
a pair of split shear ring halves mounted in a mounting groove in the stem proximal to the first end of the stem, and
a shear ring keeper device mounted over the shear ring halves to maintain the shear ring halves in position;
whereby whenever the shearable mechanism is subjected to a fluid pressure in excess of a predetermined value from the outlet passageway the shear ring halves will shear and the stem will move further into the socket in the actuator shank thereby allowing the release of backpressure.
17. A choke valve comprising:
a body having an axial through hole passing from a first side of the body to a second side of the body, an outlet passageway coaxially aligned with the through hole and positioned at the first side of the body, and a radial inlet port intersecting the through hole between the first and second sides of the body;
a valve seat coaxially housed in the through hole between the inlet port and the outlet passageway;
a valving member axially reciprocable within the through hole between a first position bearing against the valve seat and a second open position spaced away from the valve seat;
an actuator attached to the second side of the body for reciprocably moving the valving member between the first position and the second position wherein the actuator includes an axially reciprocable actuator shank having a shank socket; and
a shearable mechanism having a stem interconnecting the actuator shank and the valving member, wherein a first end of the stem is positioned in the shank socket at less than a full depth of the shank socket;
whereby whenever the shearable mechanism is subjected to fluid pressure in excess of a predetermined value from the outlet passageway the shearable mechanism will shear and the stem will move further into the shank socket thereby moving the valving member away from the valve seat to allow the release of backpressure.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A paving apparatus for placing a plurality of paving stones on a supporting surface to be paved, the apparatus comprising:
a main frame supported for movement along the supporting surface in a forward working direction;
a hopper supported on the main frame and arranged to receive castable material therein;
a plurality of molds, each comprising at least one mold cavity arranged to receive castable material from the hopper therein such that each mold cavity of the plurality of molds is arranged to form a respective one of the plurality of paving stones; and
a conveying mechanism supported on the main frame and including:
a first portion supporting the molds for respective movement from a casting position in alignment with the hopper to a placing position arranged to dispense a cast paving stone therefrom onto the supporting surface; and
a second portion supporting the molds for respective movement from the placing position back to the casting position.
2. The apparatus according to claim 1 wherein the conveying mechanism is arranged to release each mold from the first portion of the conveying mechanism at a location spaced forwardly from the second portion prior to engaging the mold with the second portion of the conveying mechanism.
3. The apparatus according to claim 1 wherein the conveying mechanism includes a casting section arranged to support each mold in the casting position and wherein the conveying mechanism is arranged to release each mold from the second portion of the conveying mechanism at the casting section prior to engaging the mold with the first portion of the conveying mechanism.
4. The apparatus according to claim 1 wherein each mold comprises a plurality of mold cavities.
5. The apparatus according to claim 4 wherein the mold cavities of each mold are arranged in a respective lateral row of cavities and wherein the molds include first and second mold types in which the mold cavities of the first mold type are staggered so as to be laterally offset from the mold cavities of the second mold type.
6. The apparatus according to claim 1 wherein the main frame includes a placing section extending in a longitudinal direction rearwardly from the first portion of the conveying mechanism at a forward end of the main frame to the second portion of the conveying mechanism at a rearward end of the main frame, the placing section being arranged to receive a longitudinally extending row of the molds in the respective placing position.
7. The apparatus according to claim 6 wherein the main frame includes a roller base arranged to support the main frame for rolling movement in the forward working direction on the longitudinally extending row of molds in the placing section between the first and second portions of the conveying mechanism.
8. The apparatus according to claim 7 wherein the roller base is centrally located between the front and rear ends of the main frame so as to be arranged to substantially fully support a weight of the apparatus thereon.
9. The apparatus according to claim 1 wherein there is provided a biasing mechanism arranged to bias each mold during placement on the supporting surface rearwardly against one of the molds previously placed on the supporting surface.
10. The apparatus according to claim 1 further comprising a metering mechanism arranged to deliver metered portions of castable material from the hopper to the molds in the casting position.
11. The apparatus according to claim 10 wherein the molds include first and second mold types which are different in configuration from one another and wherein the metering mechanism is arranged to deliver first and second metered portions to the first and second mold types respectively.
12. The apparatus according to claim 1 further comprising a packing tool supported on the main frame above the molds in the casting position, the packing tool include a packing head arranged for engaging an open side of the molds and a driver arranged to substantially vertically reciprocate the packing head so as to be arranged for packing the castable material in the molds.
13. The apparatus according to claim 11 wherein the molds include first and second mold types which are different in configuration from one another and wherein the packing head of the packing tool comprises modular sections, the driver being arranged to reciprocate different ones of the modular sections of the packing head in first and second packing modes corresponding to the first and second mold types respectively.
14. The apparatus according to claim 1 further comprising a primary packing tool supported on the main frame above the molds in the casting position so as to be arranged to pack the castable material in the molds in the casting position, and a secondary packing tool on the main frame arranged to pack the castable material in the molds in a secondary packing position forwardly in relation to packing by the primary packing tool in the casting position.
15. The apparatus according to claim 1 wherein the molds include first and second mold types which are different in configuration from one another and wherein there is provided a chute arranged to guide castable material from the hopper into each mold in the casting position, the chute including gate members mounted for sliding movement relative to the chute so as to be arranged to vary the chute between first and second configurations corresponding to the first and second mold types respectively.
16. The apparatus according to claim 1 further comprising a sweep mechanism supported on the main frame so as to be arranged to sweep respective sides of each mold when the mold is supported by the first portion of the conveying mechanism.
17. The apparatus according to claim 16 further comprising a return mechanism arranged to convey material swept by the sweep mechanism to the hopper.
18. The apparatus according to claim 1 further comprising a hammering mechanism including a reciprocating hammer arranged to engage each mold in the placing position so as to be arranged to release the respective cast paving stone from the mold.
19. The apparatus according to claim 1 wherein the conveying mechanism is arranged to dispense cast paving stones on the supporting surface in a longitudinally extending row as the main frame is displaced in the forward working direction and wherein there is provided an alignment tool on the main frame arranged to guide the main frame along a previously placed longitudinally extending row of cast paving stones as the main frame is displaced in the forward working direction.
20. The apparatus according to claim 1 wherein the main frame includes a roller base arranged to support the main frame for rolling movement on molds placed on the supporting surface in the placing position and wherein there is provided front and rear wheels at respective forward and rearward ends of the main frame, the front and rear wheels being adjustable in height relative to the roller base so as to be arranged to support the main frame thereon with the roller base spaced above the ground in a transport position.
21. The apparatus according to claim 1 wherein the main frame includes a roller base arranged to support the main frame for rolling movement on molds placed on the supporting surface in the placing position and wherein there is provided a front wheel on the main frame spaced forwardly of the roller base, the front wheel being lower in elevation than the roller base so as to be arranged for rolling movement on the supporting surface when the roller base rolls on the molds in the placing position.
22. The apparatus according to claim 21 wherein the front wheel comprises a roller which spans a majority of a width of the apparatus in a lateral direction.
23. The apparatus according to claim 21 wherein the front wheel is adjustable in position relative to the main frame in a lateral direction oriented transversely to the forward working direction.
24. The apparatus according to claim 1 further comprising a sweep mechanism supported on the main frame so as to be arranged to sweep an interior of each mold when the mold is supported by the second portion of the conveying mechanism.
25. The apparatus according to claim 1 further comprising a release sprayer mounted on the main frame and arranged to spray a mold releasing agent into each mold at a location prior to the casting position.
26. The apparatus according to claim 1 further comprising a finish sprayer mounted on a rear end of the main frame so as to be arranged to spray a finish coating on an upper surface of the cast paving stones on the supporting surface subsequent to the respective mold being engaged by the second portion of the conveying mechanism.