Direct touch type metal diaphragm valve
A direct touch type metal diaphragm valve, wherein durability of the valve, that is to say, the ensured number of continuous open/close operations of the valve, is substantially increased under conditions that an appropriate flow rate coefficient Cv is maintained, and changes of the afore-mentioned Cv value over time are mitigated by means of restricting the deformation of the valve seat over time. The afore-mentioned metal diaphragm is formed in a round, reverse-dish shape by laminating a plural number of thin stainless steel plates and a thin Nickel.Cobalt alloy plate, and its center part is bulged upward, and the maximum valve stroke of the valve is regulated to be 55% to 70% of the distance of the maximum bulge height Δh of the afore-mentioned metal diaphragm.
1. A direct touch type metal diaphragm valve comprising:
(a) a body equipped with a valve seat on a bottom face of a concave valve chamber, wherein the valve chamber communicates with a fluid inlet and a fluid outlet;
(b) a metal diaphragm disposed above the valve seat, wherein to hold hermeticity of the valve chamber, the metal diaphragm moves upward and downward so as to directly contact the valve seat by a center part of the metal diaphragm;
(c) a stem disposed above the metal diaphragm so as to descend and ascend, wherein the stem allows the center part of the metal diaphragm to descend;
(d) an actuator connected to the stem so as to allow the stem to descend or ascend; and
(e) a press adaptor disposed above an outer peripheral part of the metal diaphragm so as to hold the metal diaphragm hermetically between the press adaptor and the bottom face of a valve chamber and to control descent of the stem at a time when the valve is fully closed, wherein the metal diaphragm includes a laminated body comprising
i. a plurality of thin stainless steel plates; and
ii. a thin Nickel.Cobalt alloy plate, wherein the laminated body is formed in the shape of a round, reverse-dish with a center part bulged upward, wherein movement of the metal diaphragm is regulated so that a maximum valve stroke ΔS of the valve is 55% to 70% of a distance of a maximum bulge height Δh of the metal diaphragm.
2. A direct touch type metal diaphragm valve as claimed in claim 1 , wherein a Cv value of the valve at the time of the maximum valve stroke ΔS is made to be 0.55 to 0.8.
3. A direct touch type metal diaphragm valve as claimed in claim 1 , wherein the metal diaphragm has a bulge curvature that is 65 to 66 mm with an outer diameter of 15 mmφ, or a bulge curvature that is 62 to 63 mm with an outer diameter of 18 to 20 mmφ, or a bulge curvature that is 59 to 61 mm with an outer diameter of 24 to 26 mmφ.
4. A direct touch type metal diaphragm valve as claimed in claim 1 , wherein the metal diaphragm is a round laminated body comprising three pieces of thin stainless steel plate and one piece of thin Nickel.Cobalt alloy plate, and an outer diameter of the round laminated body is 24 to 26 mmφ, the maximum bulge height Δh is 1.2 mm to 1.3 mm, and the maximum valve stroke ΔS is 0.65 mm to 0.8 mm.
5. A direct touch type metal diaphragm valve as claimed in claim 1 , wherein the valve seat is made with PFA, the stem is provided with a valve stroke adjustment mechanism so that the valve stroke ΔS is adjusted and fixed to a prescribed set value by using the valve stroke adjustment mechanism, wherein the valve stroke ΔS is adjusted and fixed to the prescribed set value after continuous open/close operations of the valve have been performed over 3000 to 10000 times.
6. A direct touch type metal diaphragm valve as claimed in claim 2 , wherein the metal diaphragm has a bulge curvature that is 65 to 66 mm with an outer diameter of 15 mmφ, or a bulge curvature that is 62 to 63 mm with an outer diameter of 18 to 20 mmφ, or a bulge curvature that is 59 to 61 mm with an outer diameter of 24 to 26 mmφ.
7. A direct touch type metal diaphragm valve as claimed in claim 2 , wherein the valve seat is made with PFA, the stem is provided with a valve stroke adjustment mechanism so that the valve stroke ΔS is adjusted and fixed to a prescribed set value by using the valve stroke adjustment mechanism, wherein the valve stroke ΔS is adjusted and fixed to the prescribed set value after continuous open/close operations of the valve have been performed over 3000 to 10000 times.
8. A direct touch type metal diaphragm valve as claimed in claim 3 , wherein the valve seat is made with PFA, the stem is provided with a valve stroke adjustment mechanism so that the valve stroke ΔS is adjusted and fixed to a prescribed set value by using the valve stroke adjustment mechanism, wherein the valve stroke ΔS is adjusted and fixed to the prescribed set value after continuous open/close operations of the valve have been performed over 3000 to 10000 times.
9. A direct touch type metal diaphragm valve as claimed in claim 4 , wherein the valve seat is made with PFA, the stem is provided with a valve stroke adjustment mechanism so that the valve stroke ΔS is adjusted and fixed to a prescribed set value by using the valve stroke adjustment mechanism, wherein the valve stroke ΔS is adjusted and fixed to the prescribed set value after continuous open/close operations of the valve have been performed over 3000 to 10000 times.