This invention relates to an improvement of a large capacity steam trap, wherein certain disadvantages of a composite valve mechanism, which is opened and closed by utilizing the buoyancy of a float or the like, are eliminated by the addition of a bellows mechanism or the like, Instrument Manifolds to obtain a steam trap which is accurate in operation, low in cost and easy to handle and maintain, as well as being capable of discharging a large quantity of condensed water. A large capacity steam trap comprising a housing defining a sump for condensate water, said housing having an inlet and an outlet therein spaced from one another, Bellow Seal Valve a valve body positioned within the sump in said housing and comprising a horizontally arranged tubular box, PLUG VALVESsaid tubular box having a first opening at one end in communication with the outlet from said housing and a second opening at its other end communicating with said sump, at least a first valve seat located in said tubular box intermediate its first and second openings, a second valve seat located at the second opening in said tubular box, first valve means associated with said first valve seat for opening and closing flow into said tubular box from said sump, a float position within said sump and in operative engagement with said first valve means for opening said first valve means in response to a predetermined increase in the level of condensate water in said sump, second valve means associated with said second valve seat and responsive to thermal conditions within said sump for opening and closing flow through said second opening into said tubular box. In a large capacity steam trap of the usual type, when the valve is opened the valve body is attracted by the drop of dynamic pressure caused by high velocity fluid flowing at the valve portion of a composite valve mechanism, according to Bernoulli's theorem. Thus, the valve port is throttled, so that a large quantity of condensation could not be discharged in spite of the valve port having a larger aperture. An object of the present invention is to eliminate such a drawback and to assure an instant discharge of a large quantity of condensed water by keeping the valve port always opened maximally when the valve is opened. Such an object may be attained, according to the present invention, by providing the composite valve mechanism with a bellows mechanism which operates thermostatically such that in the valve opening operation, the pressure at the valve portion of said composite valve mechanism is raised by the condensed water flowing out from the valve port of said bellows mechanism to prevent the valve body of said composite valve mechanism from being attracted to the valve seat. Thus, there is no fear of throttling of the valve port and of decreasing the flow quantity of discharge, but it is always possible to keep the valve port opened maximally and yet the condensed water may be discharged also by said bellows mechanism, so that a large quantity of condensed water may be discharged in a short time. And, at the time of starting, said bellows mechanism is in the opened valve condition, so that air and cold condensed water in the piping and the apparatus may be discharged in a short time. Further, in the steam trap according to the present invention, when the condensed water is accumulated, first the float will rise to open the composite valve. When the composite valve is opened, the pressure within the valve chamber will rise and come close to the pressure on the inlet side (primary pressure), so that the difference between the primary pressure acting on the bellows mechanism and the secondary pressure on the outlet side will disappear. Thus, the bellows may be promptly contracted to open the valve due to a slight temperature drop and pressure drop accompanied therewith.

MORE NEWS