This class 200 Milwaukee Valve 1174 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 union bonnet provide higher strength and resistance to corrosion than brass. The stainless-steel seat rings equip the valve for high pressure applications and help resist corrosion over time. It has a rising stem that moves up and down with the gate that provides a visual signal (when extended) that the valve is open. This 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 400 pounds per square inch (gauge) (psig) for water, oil, and gas pressure (WOG) and 200 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 gate to start and stop the flow between the connected pipes. The class 200 valve meets Manufacturers Standardization Society (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 heavy duty service in plumbing and heating systems.
Gate valves control flow in a piping system by lifting a gate 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.