You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
FIELD OF THE INVENTION 
   The present invention relates to shut-off valves and more particularly to an inline valve to control the flow of concrete in a concrete delivery system. 
   BACKGROUND OF THE INVENTION 
   Typically, concrete is delivered at a job site to remote areas via a pump that pumps the concrete through a series of boom connected pipes terminating in a flexible delivery hose. The flow of concrete is typically controlled at a point remote from the delivery hose and thus even when the concrete flow is stopped at its source, it is not unusual for concrete to continue to flow or drip from the end of the delivery hose. This condition can be very undesirable at certain job sites. 
   One attempt to ameliorate this excessive flow condition is set forth in the current assignee&#39;s pending U.S. patent application Ser. No. 10/309,912 filed Dec. 4, 2002, which is herein incorporated by reference. In this application, a shut-off valve for use with a concrete delivery hose includes an outer rigid casing disposed around the concrete delivery hose as well as a first flexible sleeve within the casing. A second flexible sleeve is disposed within the first flexible sleeve so as to define a gas chamber between the two sleeves. A gas port extends through the casing and into the gas chamber so that pressurized gas can be introduced into the chamber causing the second sleeve to be forced radially inwardly to constrict and close the delivery hose. 
   While such shut-off valve has performed generally satisfactorily, it is desirable to provide an improved device with enhancements which will more immediately stop concrete discharge and eliminate spill and waste. 
   It is a principal object of the present invention to provide a concrete shut-off valve which is more efficiently and simply manufactured at a lower cost with a reduction in the number and machining of parts, a reduction in assembly time and the elimination of welding operations. 
   It is another object of the present invention to provide a concrete shut-off valve equipped with a relief valve and an off/on indicator. 
   It is an object of the present invention to provide a concrete shut-off valve that is easily installed and operated. 
   It is a further object of the present invention to provide a valve that is positioned on the outside of the delivery hose so that the valve is not in direct contact with the flow of the concrete. 
   It is still another object of the present invention to provide a valve that will reduce concrete spill over and/or drippage. 
   It is also an object of the present invention to provide a gas controlled shut-off valve. 
   It is an additional object of the present invention to provide various control for the shut-off valve. 
   BRIEF SUMMARY OF THE INVENTION 
   In accordance with one aspect of the invention, a shut-off valve for use with a concrete delivery hose includes a one piece, continuous, outer substantially rigid casing dimension to be disposed around the concrete hose. A single flexible sleeve is disposed within the casing and defines a gas chamber between the casing and the sleeve. A gas port extends through the casing and into the gas chamber whereby pressurized gas can be introduced into the chamber causing the sleeve to be forced radially inwardly to constrict and close upon the delivery hose. The single flexible sleeve has upper and lower ends which are folded over top and bottom ends of the rigid casing, an inner support ring disposed against an inside surface of the sleeve ends, an outer rigid support ring positioned against an outside surface of the folded over upper and lower ends of the sleeve, and fasteners being passed through the inner support rings, the folded over sleeve ends and the outer support rings to hold the casing, sleeve and inner and outer support rings together. The casing is preferably comprised of a fiberglass reinforced composite. The shut-off valve includes a relief valve connected to and in communication with the gas port for quickly exhausting gas delivered to the gas port. The shut-off valve further includes an off/on indicator connected to and in communication with the gas port for indicating open and closed positions of the shut-off valve. The off/on indicator includes a housing having an elongated passageway formed therein in communication with the gas port, the passageway having an inlet. A cylinder is fixed in the passageway and a valve element is disposed at one of the spring and normally biased by the spring to block the inlet. The valve element has an elongated plunger extending through the spring, the cylinder and the housing. The plunger has an indicating element on an end opposite the valve element, the indicating element being extendable and retractable relative to the housing depending on gas pressure in the gas port. 
   In another aspect of the invention, a shut-off valve for use with a concrete delivery hose includes an outer substantially rigid casing dimensioned to be disposed around the concrete delivery hose. Flexible sleeve structure is disposed within the casing and defines a gas chamber between the casing and the sleeve structure. A gas port extends through the casing and into the gas chamber whereby pressurized gas can be introduced into the chamber causing the sleeve structure to be forced radially inwardly to constrict and close upon the delivery hose. A relief valve is connected to and in communication with the gas port for quickly exhausting gas delivered to the gas port. An off/on indicator is connected to and in communication with the gas port for indicating open and closed positions of the shut-off valve. The casing on the sleeve structure defines a tubular cup assembly which is suspended upon the concrete delivery hose. The relief valve and the off/on indicator are located outside and alongside the cup assembly. 
   Various other features, objects, and advantages of the invention will be made apparent from the following detailed description and the drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings illustrate the best mode currently contemplated of carrying out the invention. 
     In the drawings: 
       FIG. 1  is a perspective view of a shut-off valve connected to the delivery hose of a concrete pumping system; 
       FIG. 2  is a side cross-sectional view of the valve of  FIG. 1 ; 
       FIG. 3  is an end cross-sectional view of the valve of  FIG. 2 ; 
       FIG. 4  is a representation of remote control for the valve of FIG.  1 . 
       FIG. 5  is a perspective view of an alternative embodiment of the shut-off valve constructed according to the present invention; and 
       FIG. 6  is a break-away view of the shut-off valve shown in FIG.  5 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1-4  show a shut-off valve as described in the aforementioned U.S. patent application Ser. No. 10/309,912 filed Dec. 4, 2002. 
   As seen in  FIG. 1 , a concrete control valve  10  is connected to and surrounds the concrete delivery hose  12  of a concrete pumping system  14 . Control valve  10  includes an outer rigid casing  16  in the form of three steel bands  18 ,  20  and  22 . 
   As seen in  FIG. 2 , first flexible rubber sleeve  24  is disposed in and connected to rigid casing  16 . A second flexible rubber sleeve  26  is disposed radially inwardly of first sleeve  24  and defines a gas chamber  28  between first sleeve  24  and second sleeve  26 . Together, the casing  16  and the sleeves  24 ,  26  form a tubular cuff assembly. 
   A gas port  30  ( FIG. 3 ) is disposed on middle band  20  and extends through band  20  and first sleeve  24  so that it communicates with gas chamber  28 . A gas flow control valve  32  with a manual control handle  34  and a muffler  35  is disposed on the outside of gas port  30 . Gas line  36  ( FIG. 1 ) channels a source of gas to control valve  32 . Gas flow control valve  32  is retained in place around hose  12  by a strap  38 . Gas flow control valve  32  is located beneath the concrete control valve  10 . 
   In operation, pressurized gas such as air, nitrogen or the like is introduced into chamber  28  via flow valve  32  and gas port  30 . First sleeve  24  is held in place by rigid casing  16  while second sleeve  26  expands radially inwardly to constrict delivery hose  12  to the point where the flow of concrete through delivery hose  12  is interrupted. When it is desired to resume the flow of concrete, the gas pressure is relieved so that second sleeve  26  can retract to its original position and delivery hose  12  will reopen. 
   It should be understood that control valve  32  can either be hand operated with control handle  34  or interlocked with the control system of the pumping truck or controlled remotely as shown in FIG.  4 . The remote control  40  includes a remote control box  41  connected to a cord  42  and joined to an air solenoid valve  44  having a muffler  46 , a gas inlet  48  and a gas outlet  50 . A separate remote control unit (not shown) triggers the solenoid valve  44 . 
     FIGS. 5 and 6  show an alternative embodiment according to the present invention which is similar to the principles and operations of the valve  10  shown in  FIGS. 1 through 4  with the following exceptions and/or additions. Like numbers are used to denote like parts previously described. 
   In valve  10 ′, the outer rigid casing  16 ′ is provided by a single cylindrical shell formed of a fiberglass reinforced composite. Flexible rubber sleeve  26 ′ is disposed radially inwardly of casing  16 ′ and defines gas chamber  28 ′ between casings  16 ′ and rubber sleeve  26 ′. As seen at the extreme ends of the valve  10 ′, the upper and lower ends  52 ,  53  of the rubber sleeve  26 ′ are folded over top and bottom ends  54 ,  55  of the rigid casing  16 ′. An inner metal support ring  56  is placed to the inside of the sleeve  26 ′, and an outer metal support ring  58  is positioned to the outside of the folded over portion of the sleeve  26 ′. A series of bolts  59  are passed through the inner support rings  56 , the folded over sleeve ends  52 ,  53 , the casing  16 ′ and the outer support rings  58 , and nuts  60  are attached to the shafts of the bolts  59  so as to hold the assembly tightly together without any welding. 
   An air intake/exhaust system  62  is comprised of a gas port  30 ′ in communication with a relief valve  64  and a gas line  36 ′. Relief valve  64  is equipped with a muffler  65  as seen in FIG.  5 . Gas port  30 ′ is attached, such as by drilling and tapping a hole in the shell  16 , and screwing a bushing  66  with threads into the tapped hole until the brushing  66  is secure. Once this is completed, a lock nut  67  is tightened on the bushing  66  to prevent the gas port  30 ′ from coming loose. Gas port  30 ′ extends through the casing  16 ′ so that it communicates with gas chamber  28 ′. Gas line  36 ′ channels a source of gas to gas chamber  28 ′, the flow of gas being controlled manually or by remote control as previously described. 
   Attached to a lower portion of the gas port  30 ′ is a pressure sensitive off/on indicator  68  which is in communication with the gas being selectively supplied to the gas port  30 ′. The off/on indicator  68  includes a moveable valve element  70  which is normally biased upwardly by a compression spring  72  disposed in a cylinder  73  fixed in a passageway  74  to prevent gas from entering passageway  74  in communication with a cup-like housing  75 . The valve element  70  has a depending elongated plunger  76  which passes through the compression spring  72 , the cylinder  73  and the housing  75 , and has an opposite end  77  attached to a dome-like, preferably colored, indicating element  78  which extends and retracts relative to housing  75  depending on the pressure of gas delivered to the gas port  30 ′. 
   It should be understood that the off/on indicator  68  may take other forms. For instance, one could employ a battery-operated light or sound device which is activated by gas pressure to accomplish the same concept as described above. 
   In operation, pressurized gas, such as air, is delivered through air intake/exhaust system  62  into gas chamber  28 ′ via gas port  30 ′. Rubber sleeve  26 ′ expands radially inwardly to constrict delivery hose  12  to the point where flow of concrete through hose  12  is interrupted. At the same time, gas pressure in the passageway  74  will act to unseat valve element  70  against the bias of spring  72  and move plunger  76  so that the indicating element  78  will extend away from the housing  75  to give visual indication to the operator that the shut-off valve  10 ′ is closed upon the hose  12 . When it is desired to open the shut-off valve  10 ′, delivery of gas to gas line  36 ′ is stopped and pressurized gas is exhausted quickly through the relief valve  64  and muffler  65 . As this happens, the spring  72  will move the valve element  70  to block passageway  74  so that the plunger  76  and indicating element  78  will retract inside housing  75  (as shown in phantom lines of  FIG. 6 ) to indicate to the operator that the valve  10 ′ is open whereupon concrete may again flow freely through hose  12 . 
   It should be understood that the shut-off valve  10 ′ operates in a more efficient manner to more quickly exhaust gas due to the inclusion of the relief valve  64  which enables a reduction of about 50 percent (from eight seconds to four seconds) in the opening/closing time of the valve  10 ′. This improvement in reaction time is conveniently transmitted visually to the operator via the pressure responsive off/on indicator  68 . It should be further appreciated that the present invention involves a reduction in the machining and number of components, a reduction in assembly time and the elimination of welding, all of which contribute to lower cost with an improved response. 
   It is recognized that other equivalents, alternatives, and modifications aside from those expressly stated, are possible and within the scope of the appended claims.

Summary:
A shut off valve for use with a concrete delivery hose includes a single flexible cylindrical sleeve disposed within a one piece, continuous rigid casing that surrounds the hose. A gas chamber is defined between the sleeve and the casing so that when pressurized gas is forced into the chamber, the sleeve will be displaced radially inwardly to constrict the hose and stop the flow of concrete. The shut-off valve also includes a relief valve for quickly exhausting gas from the valve, and an off/on indicator for indicating open/closed positions of the valve.