An apparatus for controlling flow of fluid comprising: a valve body 102 that comprises an inlet port 116 and an outlet port 118; a hollow piston 104 that is coupled to said valve body 102, wherein said hollow piston 104 comprises a hollow portion 106 surrounded by a side wall, and at least one opening 108 within said hollow portion 106 along said side wall of said hollow piston 104; a guide ring 110 that is coupled to said hollow piston 104, wherein said guide ring 110 dispenses support to said hollow piston 104 when said hollow piston 104 moves linearly upwards or downwards inside said valve body 102; a plurality of sealing rings 111-113 that comprises a bottommost sealing ring 111 and a topmost sealing ring 113, wherein said topmost sealing ring 113 is coupled to said guide ring 110, the guide ring being provided in said valve body 102 above said topmost sealing ring 113, wherein each of said plurality of sealing rings 111-113 occludes flow of fluid to said outlet port 118 from said inlet port 116 so as to allow flow of fluid only through said hollow portion 106 of said hollow piston 104; wherein said at least one opening 108 within said hollow portion 106 along said side wall of said hollow piston 104 enables flow of fluid partially to said outlet port 118 from said inlet port 116, when said hollow piston 104 is moved upwards such that said at least one opening 108 within said hollow portion 106 along said side wall of said hollow piston 104 is positioned partially above said topmost sealing ring 113; wherein said at least one opening 108 within said hollow portion 106 along said side wall of said hollow piston 104 enables a full flow of fluid through said hollow portion 106 towards said outlet port 118 from said inlet port 116 when said hollow piston 104 is moved upwards such that each of said at least one opening 108 within said hollow portion 106 along said side wall of said hollow piston 104 is positioned fully above said guide ring 110 and said topmost sealing ring 113; wherein said topmost sealing ring 113 occludes a flow of fluid towards said outlet port 118 from said inlet port 116 when said hollow piston 104 is moved downwards such that each of said at least one opening 108 within said hollow portion 106 along said side wall of said hollow piston 104 is positioned fully below said bottommost sealing ring 111; wherein the inlet port 116 is positioned in the valve body 102 above the guide ring 110; and wherein the shape of the at least one opening 108 within the hollow portion 106 along the side wall of the hollow piston 104 includes a rectangular shape or a V-shape. a valve body 102 that comprises an inlet port 116 and an outlet port 118; a hollow piston 104 that is coupled to said valve body 102, wherein said hollow piston 104 comprises a hollow portion 106 surrounded by a side wall, and at least one opening 108 within said hollow portion 106 along said side wall of said hollow piston 104; a guide ring 110 that is coupled to said hollow piston 104, wherein said guide ring 110 dispenses support to said hollow piston 104 when said hollow piston 104 moves linearly upwards or downwards inside said valve body 102; a plurality of sealing rings 111-113 that comprises a bottommost sealing ring 111 and a topmost sealing ring 113, wherein said topmost sealing ring 113 is coupled to said guide ring 110, the guide ring being provided in said valve body 102 above said topmost sealing ring 113, wherein each of said plurality of sealing rings 111-113 occludes flow of fluid to said outlet port 118 from said inlet port 116 so as to allow flow of fluid only through said hollow portion 106 of said hollow piston 104; wherein said at least one opening 108 within said hollow portion 106 along said side wall of said hollow piston 104 enables flow of fluid partially to said outlet port 118 from said inlet port 116, when said hollow piston 104 is moved upwards such that said at least one opening 108 within said hollow portion 106 along said side wall of said hollow piston 104 is positioned partially above said topmost sealing ring 113; wherein said at least one opening 108 within said hollow portion 106 along said side wall of said hollow piston 104 enables a full flow of fluid through said hollow portion 106 towards said outlet port 118 from said inlet port 116 when said hollow piston 104 is moved upwards such that each of said at least one opening 108 within said hollow portion 106 along said side wall of said hollow piston 104 is positioned fully above said guide ring 110 and said topmost sealing ring 113; wherein said topmost sealing ring 113 occludes a flow of fluid towards said outlet port 118 from said inlet port 116 when said hollow piston 104 is moved downwards such that each of said at least one opening 108 within said hollow portion 106 along said side wall of said hollow piston 104 is positioned fully below said bottommost sealing ring 111; wherein the inlet port 116 is positioned in the valve body 102 above the guide ring 110; and wherein the shape of the at least one opening 108 within the hollow portion 106 along the side wall of the hollow piston 104 includes a rectangular shape or a V-shape.