Abstract:
A wear resistant rubber hose for transferring fluid containing abrasive material such as crushed stone, coral, etc. comprises an inner surface rubber and a filling body having a rigidity which is considerably higher than that of the inner surface rubber embedded directly inside the inner peripheral surface thereof. Two embodiments of the filling body are provided. In one embodiment, the filling body is composed of a chain-shaped continuous body, while in another embodiment the filling body is composed of a reinforcing ring comprising a circumferentially wound core and sphere-shaped rotary bodies fitted onto the core.

Description:
BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     This invention relates to wear resistant rubber hoses and more particularly to a wear resistant rubber hose for transferring fluid containing abrasive material such as crushed stone, coral, etc. 
     (2) Description of the Prior Art 
     In transferring mud dug from the sea-bed together with the sea water by means of a conventional rubber hose, sharp corners of the crushed stone or coral mixed in the mud strike against the inner surface of the rubber hose, thus inducing the premature tear failure thereof and hence deteriorating its durability. 
     SUMMARY OF THE INVENTION 
     An object of the invention, therefore, is to provide a wear resistant rubber hose which can eliminate the above described drawback which has been encountered with the prior art technique, that is, which has a significantly high durability for a total period in the use of rubber hose. 
     A feature of the invention is the provision in a wear resistant rubber hose comprising an inner surface rubber, a reinforcing layer for covering said inner surface rubber and an outer cover rubber for covering said reinforcing layer, of the improvement comprising a filling body having a rigidity which is considerably higher than that of said inner surface rubber and embedded directly inside the inner peripheral surface thereof. 
     The filling body may be composed of hard particles, preferably a steel chain. The hard particles can improve the wear resistant property of the inner periphery of the inner surface rubber. But, if the inner surface of the rubber becomes damaged to expose the hard particles, they tend to be easily dug out. As a result, the inner surface rubber becomes significantly worn, particularly after a given period in the use of the rubber hose. 
     In accordance with the invention, in order to eliminate such drawback, the filling body is composed of a chain-shaped continuous body wound around a center axis of the hose along the inner periphery thereof. Alternatively, the filling body may be composed of a chain consisting of a series of links connected one to another and each formed of an open ring whose opposed ends form a gap therebetween. The chain may also consist of a series of links connected one to another and each formed of a closed ring and connected to adjacent links with a gap formed therebetween. In the final embodiment, the filling body may be composed of a reinforcing ring comprising a number of spaced apart circumferentially wound cores surrounding the center axis of the hose and arranged side by side in the axial direction of the hose and a number of spaced apart sphere-shaped rotary bodies fitted onto each circumferentially wound core. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The invention will now be described in greater detail with reference to the accompanying drawings, wherein: 
     FIG. 1 is a cross-sectional view of a conventional rubber hose illustrating the mode of gradually damaging its inner surface rubber by an abrasive fluid; 
     FIG. 2 is a cross-sectional view of one embodiment of a wear resistant rubber hose according to the invention; 
     FIG. 3a is a partial perspective view of a preferred embodiment of a filling body used in the rubber hose shown in FIG. 2; 
     FIG. 3b is a partial perspective view of another preferred embodiment of a filling body used in the rubber hose shown in FIG. 2; 
     FIG. 4 is a perspective view of another embodiment of a wear resistant rubber hose according to the invention, a part being broken away so as to show a further preferred embodiment of a filling body used therein; 
     FIG. 5 is a partial cross-sectional view of the rubber hose shown in FIG. 4 showing its initial condition at a given period of time in the use of the rubber hose; and 
     FIG. 6 is a partial cross-sectional view of the rubber hose shown in FIG. 4 and showing its condition on and after a given period of time in the use of the rubber hose. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In FIG. 1 is shown a conventional rubber hose 1. Such rubber hose 1 usually has an inner diameter of the order of 760 mm and a length of the order of 1.7 m and comprises an inner surface rubber 2 having a thickness of about 80 mm, a reinforcing layer 3 covering the outer periphery of the inner surface rubber 2 and an outer cover rubber 4 covering the reinforcing layer 3 and provided at its both ends with a metal flange 5 made integral therewith. If such conventional rubber hose is used for transferring mud together with sea water, abrasive material 6 contained in the fluid is struck against the inner surface rubber 2, thereby damaging it as shown by the undulations in FIG. 1. 
     In FIG. 2 is shown one embodiment of a wear resistant rubber hose according to the invention. In the present embodiment, a rubber hose 1 is provided directly inside of the inner surface rubber 2 with a number of spaced apart chain-shaped continuous bodies 7. These chain-shaped continuous bodies 7 are arranged side by side along the inner periphery of the inner surface rubber 2 and wound around the center axis of the rubber hose 1 and embedded therein. It is preferable to make use of a chain 7 consisting of a series of links connected one to another and wound helically around the center axis of the rubber hose 1. The inner surface rubber 2 is covered with a reinforcing layer 3 which can withstand the internal pressure applied to the rubber hose 1 and the reinforcing layer 3 is covered with an outer cover rubber 4 having a thickness of the order of 5 mm. 
     In FIG. 3a is shown one preferred embodiment of a filling body according to the invention. In the present embodiment, the filling body is composed of a steel chain 7 consisting of a series of links connected to one another. Each link is formed of an open C-shaped ring whose opposed ends form a gap 8 therebetween. Each link has a diameter of the order of 10 mm. 
     In FIG. 3b is shown another preferred embodiment of a filling body according to the invention. In the present embodiment, the filling body is composed of a chain 7 consisting of a series of links connected to one another. Each link is formed of a closed ring and connected to adjacent links with a gap 9 formed therebetween. 
     In the rubber hose constructed as above described according to the invention, in its initial condition shown in FIG. 2, the thickness of the inner surface rubber 2 is large and the steel chain 7 constituting the filling body functions to reinforce the inner surface rubber 2 and hence improve the initial durability thereof against the abrasive fluid. 
     If the inner surface rubber 2 becomes worn to reduce its thickness, the steel chain 7 is exposed out of the inner periphery of the inner surface rubber 2 and brought into contact with the fluid being transferred or the abrasive material such as crushed stones, coral, etc. contained therein. As a result, it is possible to effectively prevent any further wear of the inner surface rubber 2 and hence improve the durability of the rubber hose after a given period in the use thereof. 
     In the case of using as the filling body the steel chain 7 shown in FIG. 3a, the steel chain 7 functions to particularly increase the resistance against the digging action due to the abrasive fluid and hence further improve the durability of the rubber hose. That is, if the internal pressure of the fluid being transferred is exerted on the inner surface rubber 2, a local stress is produced in that part of the inner surface rubber 2 which is bound by the steel chain 7. As a result, the chain 7 formed of the C-shaped open rings becomes resiliently deformed to effectively alleviate the local stress concentrated into the inner surface rubber 2. 
     The steel chain 7 shown in FIG. 3b also functions to particularly increase the resistance against the digging action due to the abrasive fluid and hence further improve the durability of the rubber hose. 
     That is, if the internal pressure of the fluid being transferred is exerted on the inner surface rubber 2, a local stress is produced in that part of the inner surface rubber 2 which is bound by the steel chain 7. As a result, the chain 7 formed of closed links connected with each other through the gaps 9 functions to compress and deform the rubber in the gaps 9 and hence absorb and effectively alleviate the local stress concentrated into the inner surface rubber 2. 
     As stated hereinbefore, the rubber hose for transferring fluid containing abrasive material according to the invention can significantly improve the wear resistant property of the inner surface rubber thereof and hence effectively improve the durability of the rubber hose. 
     In FIG. 4 is shown another embodiment of a wear resistant rubber hose according to the invention. In the present invention, use is made of a reinforcing ring R as the filling body. The reinforcing ring R is composed of a number of sphere-shaped rotary bodies 10 each having a diameter of the order of 30 mm and circumferentially wound cores 11 spaced apart from each other and each formed of a steel cord usually used as a tire cord and for rotatably supporting respective rotary bodies 10. In the present embodiment, the reinforcing ring R is helically wound around the center axis of the hose 1 along its inner periphery and embedded in an inner surface rubber 2 having a thickness of the order of 80 mm. 
     Similar to the embodiment shown in FIG. 2, the inner surface rubber 2 is covered with a reinforcing layer 3 which can withstand the internal pressure applied by the abrasive fluid to the hose 1 and which is also covered with an outer cover rubber 4 having a thickness of the order of 5 mm. 
     In the rubber hose constructed as above described according to the invention, in the beginning the thickness of the inner surface rubber 2 is large as shown in FIG. 5, and the reinforcing ring R embedded in it surface rubber 2 functions to reinforce the inner against the abrasive fluid and hence improve the initial durability of the rubber hose. If the inner surface rubber 2 becomes worn and thin as shown in FIG. 6, the rotary bodies 10 are exposed out of the inner periphery of the inner surface rubber 2 and brought into contact with the fluid being transferred or abrasive material such as crushed stone or coral contained therein and hence become rotated. As a result, the frictional resistance of the rotary body 10 against the abrasive fluid is decreased to effectively prevent any further progress of wear of the inner surface rubber 2, thereby improving the durability of the rubber hose 1. 
     In order to prevent the rotary bodies 10 from being displaced in the axial direction of the rubber hose 1, it is preferable that the circumferentially wound core 11 is provided with projections 11a. In addition, it is desirous to cover the rotary bodies 10 with cellophane paper or a mold releasing agent layer in the case of embedding it in the inner surface rubber 2. 
     In the present embodiment, the circumferentially wound core 11 is helically arranged, but it may alternatively be composed of a plurality of annular rings spaced apart from each other and coaxially arranged side by side in the axial direction of the hose 1. 
     As stated hereinbefore, the rubber hose for transferring a fluid containing abrasive material according to the present embodiment can also effectively improve the durability of the rubber hose.