low pressure

& a. A. As subst .: A small degree of pre ure or expansive force. B. As adj .: Having only a small degree of expansive force, and therefore exerting a low degree of pre ure. Low - pre ure Engine: Steam - eng in .: An engine in which a condenser is used, and whose safety-valve is loaded at from four to six pounds to the square inch. The terms high and low - pre ure steam were formerly held to mean saturated steam at a pre ure above or below that which will sustain a column of thirty inches of mercury, at the boiling heat of water, 212° F. The term low - pre ure signifies in this country a pre ure of not over thirty-five pounds to the square inch.