This class 125 Milwaukee Valve 148 series bronze gate valve has a rising stem and female National Pipe Taper (NPT) threads on both ends. The bronze construction, solid wedge gate, and threaded bonnet provide higher strength and resistance to corrosion than brass. It has a rising stem that moves up and down with the gate to offer a visual signal (when extended) that the valve is open. The stem design and graphite internal packing also prevent the stem threads from coming into contact with flow to avoid corrosion to extend valve life. The maximum pressure is 200 pounds per square inch (gauge) (psig) for water, oil, and gas pressure (WOG) and 125 psig for saturated steam pressure. It has female NPT threads on both ends for connecting to male threaded pipes. Mounted on top of the valve, a manually operated malleable iron hand wheel activates the inside screw mechanism, which lifts and lowers the wedge to start and stop the flow between the connected pipes. This class 125 valve meets Manufacturers Standardization Society (MSS) SP-80 standard (excluding the 4-inch model, as it has a split wedge and bolted bonnet and does not meet MSS SP-80) for quality assurance. Class is a standard relating to tolerance, construction, dimension, and wall thickness, but it is not a direct measurement of maximum working pressure. The valve is appropriate for use in general service in plumbing and heating systems. Gate valves control flow in a piping system by lifting a wedge out of the path of steam, fluids, or gases. They are designed to block or permit flow, as the vibrations and force of flow repeatedly striking a partly lowered gate can damage the gate and seats. To accommodate different flows and pressure requirements, gates come in four types: solid wedge (appropriate for almost all liquid service), flexible wedge (appropriate for steam service), split wedge (appropriate for normal temperature, non-condensing gas and liquid service, including corrosive service), and parallel disk (appropriate for high and low pressure applications). Hand wheels or levers activate the screw mechanism in the valve’s bonnet, which comes in various designs, to open and close the gate. Union bonnets are preferable for building service piping, threaded-in (or screw-in) bonnets work well for lighter-duty usage, and bolted body-bonnet connections are used primarily in iron multi-turn valves. Most gate valves have either a rising stem, which moves up and down with the gate, or a non-rising stem, which remains fixed in place. When closed, the gate and its seats form tight planar sealing surfaces, ideal for linear liquid flow. Gate valves are used in air, gas, liquid, and steam applications. The Milwaukee Valve Company manufactures manual and actuated valves, controls, and control accessories. The company, founded in 1901, and headquartered in New Berlin, WI, meets International Organization for Standardization (ISO) 9001:2008 and 14001:2004 standards.
