초록 ▼

A gate valve according to the present invention including a first valve plate having a valve opening and a second valve plate connected to the first valve plate via a first bellows, in which the rigidity and the like of the valve plates, a valve rod, and the like can be reduced as compared to that i

A gate valve according to the present invention including a first valve plate having a valve opening and a second valve plate connected to the first valve plate via a first bellows, in which the rigidity and the like of the valve plates, a valve rod, and the like can be reduced as compared to that in a conventional art by canceling the differential pressure.

대표청구항 ▼

A gate valve according to the present invention including a first valve plate having a valve opening and a second valve plate connected to the first valve plate via a first bellows, in which the rigidity and the like of the valve plates, a valve rod, and the like can be reduced as compared to that i

A gate valve according to the present invention including a first valve plate having a valve opening and a second valve plate connected to the first valve plate via a first bellows, in which the rigidity and the like of the valve plates, a valve rod, and the like can be reduced as compared to that in a conventional art by canceling the differential pressure. g the lower end of the shaft. 11. The motor-operated valve set forth in any one of claims 1 to 5 wherein the valve element has a recess formed on an outer peripheral surface thereof, and, in the recess, there is provided a slider made of a low friction material. 12. The motor-operated valve set forth in any one of claims 1 to 5 wherein the shaft has an end directly engaging with a recess formed on a top wall of a valve housing. 13. The motor-operated valve set forth in any one of claims 1 to 5 wherein the shaft has an end rotatably supported by a shaft supporting piece, and the shaft supporting piece has a projection engaging with a recess formed on a top wall of a valve housing. 14. The motor-operated valve set forth in any one of claims 1 to 5 wherein, between the shaft supporting piece and a top surface of the rotor, there is provided a compressed spring for urging downward the rotor. 15. The motor-operated valve set forth in claim 14 wherein, between the valve element and the valve main body, there is provided another compressed spring urging downward the valve element. 16. The motor-operated valve set forth in claim 14 wherein, between the valve element and the valve main body, there is provided further another compressed spring urging upward the valve element. 17. The motor-operated valve set forth in any one of claims 1 to 5 wherein the internal thread is provided separately from the valve element to be integrated on the valve element afterward. 18. The motor-operated valve set forth in any one of claims 1 to 5 wherein the valve head is provided separately from the valve element to be integrated on the valve element afterward. 19. The motor-operated valve set forth in any one of claims 1 to 4 wherein the valve head has a disengagement preventing member at a top portion thereof and has a spring receiving portion at an intermediate portion thereof, the valve head being disposed at a lower end of the valve element, and, between the spring receiving portion and the lower end of the valve element, there is provided further another compressed spring. 20. The motor-operated valve set forth in claim 19 wherein the joining portion has an upper end shoulder abutting against a flat face of the bearing when the needle valve is fully closed, so that the rotation of the rotor stops. 21. The motor-operated valve set forth in any one of claims 1 to 4 wherein the internal thread is preparatorily formed as an insert from the same synthetic resin material as the valve element. 22. The motor-operated valve set forth in any one of claims 1 to 4 wherein the bearing is made of a sintered metal. 23. The motor-operated valve set forth in any one of claims 1 to 4 wherein, between the bearing and the valve head, there is a plate piece having an elastic character for urging downward the valve element in an initialization state of the valve element.