Description

BALL VALVE HAVING BACKFLOW PREVENTION UNIT

Technical Field

[1] The present invention relates, in general, to ball valves having backflow prevention units and, more particularly, to a ball valve having a backflow prevention unit in which a ball valve structure and a check valve structure are integrated into a single body, thus having both a fluid flow turning on/off function and a fluid backflow prevention function. Background Art

[2] As well known to those skilled in the art, a ball valve is a kind of control valve, which controls the flow of various kinds of fluid. The ball valve controls the flow of fluid using a method, in which the flow of fluid is allowed or blocked by rotating an on/off ball in a direction parallel or perpendicular to the direction in which fluid linearly flows. A plug valve and a butterfly valve are representative examples of such ball valves, which have been developed and used to date. These ball valves have been widely used due to the reliability of construction thereof and convenience of operation thereof.

[3] Meanwhile, check valves allow fluid to flow in only one direction and are installed in various kinds of pipelines to prevent backflow of fluid.

[4] Typically, in a pipeline system for carrying fluid, a ball valve and a check valve are installed in a single pipeline at consecutive front and rear positions, respectively. In other words, the pipeline system for carrying fluid includes a pump, which supplies fluid under pressure, an on/off valve, such as a ball valve, which controls a flow rate of fluid, and a check valve, which is provided between the pump and the on/off valve to prevent the pump or other components from being damaged by the backflow of fluid which may occur in an emergency, such as malfunction of the pump or power failure, and also when the pump is normally stopped. That is, when fluid undesirably flows backwards, an on/off disk of the check valve is rapidly closed, thus preventing the components from being damaged due to the backflow. Disclosure of Invention

Technical Problem

[5] However, in the conventional pipeline system, because the ball valve for opening or closing (turning on or off) the flow of fluid and the check valve for backflow prevention are installed in the same pipeline at consecutive positions, a relatively large space for installation of the valves is required. Furthermore, the number of valve assembly processes and pipe connection processes are increased, with the result that

the working time is markedly increased.

[6] In addition, to cope with leakage of fluid at joints of the valves, a separate sealing process is required at every valve joint.

[7] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide an integrated ball check valve in which a ball valve structure and a check valve structure are integrated into a single body, such that only the single valve can conduct both a fluid flow turning on/off function and a fluid backflow prevention function.

[8] Another object of the present invention is to provide an integrated ball check valve which integrates the ball valve structure and the check valve structure into a single body, thus reducing the number of valves and elements pertaining to a valve connection joint, thereby reducing the installation cost of the valve, increasing the productivity due to a reduction of the number of assembly processes, and reducing the weight of the entire pipeline system. Technical Solution

[9] In order to accomplish the above objects, the present invention provides a ball valve, including: a valve body coupled at the opposite ends thereof to respective pipes, which form a fluid passage therein; an on/off ball installed in the valve body so as to be rotatable, the on/off ball having therein a passing hole, through which fluid flows; a stem coupled to the on/off ball to rotate the on/off ball; a control lever coupled to the stem; and a backflow prevention unit installed in the passing hole of the on/off ball.

[10] In the present invention having the above-mentioned construction, because a ball valve structure and a check valve structure are integrated into a single valve, the single valve can conduct both a fluid flow turning on/off function and a fluid backflow prevention function. Therefore, the multi-functional valve of the present invention can contribute greatly to strengthen international competitiveness.

[11] Furthermore, in the present invention, because the backflow prevention unit is provided in the on/off ball, the entire size of the valve is prevented from increasing. As well, the number of valves installed in a single pipeline is reduced. Therefore, the valve connection process is simplified, and costs of maintaining and repairing elements pertaining to the valve connection and effort pertaining thereto can be reduced.

Brief Description of the Drawings

[12] FIG. 1 is a view illustrating the internal construction a ball valve according to the present invention; [13] FIG. 2 is a view illustrating the construction of an on/off ball having a backflow prevention unit according to the present invention; and [14] FIG. 3 is a view illustrating the construction of the backflow prevention unit, from

which a stopper pin has been removed, according to the present invention.

[15] *Description of the elements in the drawings*

[16] (10): valve body (20): on/off ball

[17] (21): passing hole (22): inclined protrusion

[18] (30): stem (31): ball coupling part

[19] (32): flange (33): rotating force transmitting part

[20] (40): control lever (50): backflow prevention unit

[21] (51): hinge pin (52): disk

[22] (53): spring (54): stopper pin

[23] (55): rubber seat

Best Mode for Carrying Out the Invention

[24] FIG. 1 is a view illustrating the internal construction a ball valve according to the present invention. FIG. 2 is a view illustrating the construction of an on/off ball having a backflow prevention unit according to the present invention. FIG. 3 is a view illustrating the construction of the backflow prevention unit, from which a stopper pin has been removed, according to the present invention. The ball valve of the present invention includes a valve body 10, the opposite ends of which are connected to pipes that form a fluid passage, and an on/off ball 20, which is rotatably installed in the valve body and has therein a passing hole 21, through which fluid flows. The ball valve further includes a stem 30, which is coupled to the on/off ball 20 to rotate the on/off ball, a control lever 40, which is coupled to the stem 30, and a backflow prevention unit 50, which is installed in the passing hole 21 of the on/off ball.

[25] The stem 30 is coupled at a first end thereof to the on/off ball 20 and is coupled at a second end thereof to the control lever 40 such that the on/off ball 20 in the valve body 10 is rotated by the rotation of the control lever 40.

[26] In detail, the stem 30 includes a ball coupling part 31, which is coupled to the on/off ball 20, a flange 32, which prevents the stem 30 from being undesirably removed from the valve body 10, and a rotating force transmitting part 33, which is supported by the valve body 10.

[27] The control lever 40 is coupled at one end thereof to the second end of the stem 30, so that when a user rotates the control lever 40, the stem 30 and the on/off ball 20, which is disposed in the valve body 10, are rotated, thus opening or closing a fluid passage.

[28] Furthermore, sealing rings 60 are interposed between the on/off ball 20 and the valve body 10 to prevent friction therebetween and fluid leakage. A packing 70 is interposed between the stem 30 and the valve body 10 to prevent friction therebetween and fluid leakage.

[29] The backflow prevention unit 50 is installed in the passing hole 21 of the on/off ball such that it is disposed in the fluid passage of the valve. The backflow prevention unit 50 includes a disk 52, which is provided in the passing hole 21 of the on/off ball so as to be rotatable using a hinge pin 51 and is divided into two left and right pieces, and a spring 53, which is fitted over the hinge pin 51 and elastically supports the disk 52 such that it is operated in conjunction with the disk 52. The backflow prevention unit 50 further includes a stopper pin 54, which is provided in the on/off ball 20 at a position spaced apart from the hinge pin 51 by a predetermined distance to delimit the rotation ranges of the left and right pieces of the disk 52, and a rubber seat 55, which is provided around a portion of the inner surface of the passing hole which contacts the disk 52.

[30] Furthermore, an inclined protrusion 22 is provided on the inner surface of the passing hole of the on/off ball, in which the backflow prevention unit is installed, so that the disk of the backflow prevention unit comes into close contact with the inclined protrusion 22. That is, the rubber seat 55 of the backflow prevention unit is attached to one surface of the inclined protrusion 22.

[31] In the backflow prevention unit 50, when fluid flows in a normal direction, the disk pushes the spring and rotates around the hinge pin towards the stopper pin, thus opening the passing hole of the on/off ball, thereby allowing the flow of fluid. However, when fluid flows backwards, the disk is brought into close contact with the inclined protrusion, which is provided on the inner surface of the passing hole, by the elastic force of the spring, thus closing the passing hole, thereby preventing fluid from flowing backwards.

[32] The installation of the on/off ball and the installation of the backflow prevention unit in the passing hole of the on/off ball are derived from the methods of assembling the well-known ball valve and check valve, therefore further explanation is deemed unnecessary.

[33] As described above, in the present invention, the ball valve, which controls the flow of fluid, is installed in the fluid passage, and the backflow prevention unit, which prevents backflow of fluid, is installed in the on/off ball of the ball valve. Therefore, the single valve can conduct both kinds of fluid control functions.

[34] Although the preferred embodiment of the present invention has been disclosed for illustrative purposes, the present invention is not limited to the embodiment. Furthermore, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Therefore, these modifications, additions and substitutions must be regarded as falling within the bounds of the present invention.