Method of making an actuating member for a thermostatically controlled valve

In a method of making a thermostatically controlled valve having a body provided with a valve seat, a closure member mounted for guided movement relative to the body into and out of engagement with the valve seat to open and close the valve, means biasing the closure member to the closed portion, and a temperature-responsive actuating member operatively connected to the body and the closure member for actuating the closure member, the actuating member having a shape memory effect whereby its modulus of elasticity varies with temperature such that it expands little at temperatures up to a critical temperature but expands rapidly at temperatures above the critical temperature, the critical temperature being that temperature at which the valve begins to open by rapid expansion of the actuating member, the improvement comprising the steps of:

• (a) forming the actuating member with a length greater at said critical temperature than a predetermined length required to hold the closure member in the start-to-open position of the valve,
• (b) heating the actuating member to its critical temperature, and
• (c) removing excess material from the actuating member while it is at its critical temperature so as to reduce the length of the actuating member to the said predetermined length.