Patent ID: 7868202

Claim:
A method for producing (meth)acrolein or (meth)acrylic acid by carrying out gas phase catalytic oxidation reaction of propane, propylene, isobutylene or (meth)acrolein with an oxygen-containing gas using an inorganic salt as a reaction temperature adjusting heat medium, characterized in that a material of a gland packing member which seals a body part of a regulating valve arranged on a heat medium feeder and controls supply and circulation velocity of the heat medium and a rotation axis that interfits to said body part, in such a manner that the gland packing member and the body part of the regulating valve can perform sliding, is a mica-based material, wherein the gland part of said regulating valve includes a heating jacket, and wherein an actuator of said regulating valve has a ratio (sliding frictional force between the body part and a stem interfitting thereto)/(an actuator maximum generation force) of 0.2 or less in the state of not flowing a fluid.