Mixing delivery over-flow valve double seal assistant

[0015] Example one

[0016] As shown in Figures 1 and 2, the double sealing pair of this mixed transport overflow valve includes an upper sealing pair and a lower sealing pair 1, which are arranged oppositely. The upper sealing pair is arranged at the lower end of the valve core, and the lower sealing pair 1 is fixedly installed on the valve body 5. The upper and lower sealing pair 1 is provided with a flange along the upper end of the inner circumference, and its section is knife-edge. The upper sealing pair includes a sealing ring 2, a ferrule 3, and a sealing ring 4. The sealing ring 2 is fixed under the valve core 6 by a fixing block 7 On the end face, the sealing ring 2 is embedded in the upper ring groove 7-1 of the fixed block 7; the sealing ring 4 is embedded in the lower ring groove 6-1 on the lower end surface of the valve core 6 through the ferrule 3 and the fixed ring 8, the ferrule 3 is located on the outer circumference of the sealing ring 4, the fixed ring 8 is located on the inner circumference of the sealing ring 4, the upper end of the inner circumference of the sealing ring 4 is provided with a flange, the cross section of the sealing ring 4 is in the shape of "", and the upper end of the fixed ring 8 is provided with a corresponding step The structure fits with the inner peripheral surface and the lower end surface of the horizontal flange, and the inner peripheral surface of the sealing ring 4 and the outer peripheral surface of the fixing ring 8 are provided with a gap; the lower end of the outer circumference of the sealing ring 4 is also provided with an inverted cone surface. When the valve is closed, the outer circumferential surface of the sealing ring 2 is in clearance fit with the inner circumferential surface of the lower sealing pair 1; the flange of the lower sealing pair 1 is in contact with the lower end surface of the ferrule 3.

[0017] The outer circumferential surface of the sealing ring 2 and the inner circumferential surface of the lower sealing pair 1 must not have any contact, but the gap is small, and the amount of the gap varies depending on the specifications and sizes of the double sealing pair of the mixed delivery overflow valve. The gap between the inner circumferential surface of the sealing ring 4 and the outer circumferential surface of the fixed ring 8 varies depending on the specifications and dimensions of the double sealing pair of the mixing relief valve, and the size of the gap is determined by the pressure that the medium can form here.

[0018] The double seal pair of this mixed conveyance relief valve works as follows: (1) When the valve is in the closed state, the flange of the lower seal pair 1 is in contact with the lower end surface of the upper seal pair ring 3, and bears the axial force. (2) There is a certain gap between the outer circumferential surface of the upper seal sub-sealing ring 2 and the inner circumferential surface of the lower seal sub 1, and the inner circumferential surface of the upper seal sub-sealing ring 4 and the outer circumferential surface of the fixed ring 8 There is also a certain gap. When the valve core is in the closed state, the upper secondary sealing ring 2 does not work, and fluid enters the gap between the inner peripheral surface of the upper secondary sealing ring 4 and the outer peripheral surface of the fixed ring 8. Under the action of fluid pressure, the inverted tapered surface of the lower end of the outer periphery of the lower sealing ring 4 is attached to the flange of the lower sealing ring 1, so that the lower sealing ring 4 can achieve self-tightening sealing to ensure the sealing of the valve; (4) When the spool is in a low-flow opening state, the gap between the outer circumferential surface of the upper seal sub-sealing ring 2 and the inner circumferential surface of the lower seal sub 1 acts as a damping function to prevent the valve from generating hydraulic vibration.