There are five pressure methods for throttling devices in terms of orifice plates: corner joint pressure, flange pressure, diameter pressure, theoretical pressure and pipe joint pressure. As far as the nozzle is concerned, there are only two types: angle joint pressure and diameter pressure.(1) Corner connection pressureThe distance between the axis line of the pressure hole on the upstream and downstream sides and the front and rear ends of the orifice plate (nozzle) is equal to half of the diameter of the pressure hole, or equal to half the width of the pressure ring gap, so the pressure hole penetration point and the end face of the orifice plate Exactly flat, the corner connection pressure includes the annular chamber pressure and the separate drilling pressure.(2) Flange pressureThe distance from the center of the pressure-taking hole on the upstream and downstream sides to the front and rear faces of the orifice is (25.4±0.8) mm.(3) Diameter pressureThe distance between the center of the pressure hole on the upstream side and the front face of the orifice (nozzle) is 1D, and the distance between the center of the pressure hole on the downstream side and the rear face of the orifice (nozzle) is 1/2D.(4) Theoretical pressure methodThe distance from the center of the pressure hole on the upstream side to the front end surface of the orifice plate is 1D ± 0.1D, and the distance from the center line of the pressure hole on the downstream side to the back end surface of the orifice plate varies with the value of β=d/D.(5) Pipe connection pressureThe center line of the pressure hole on the upstream side is 2.5D from the front end of the orifice plate, and the center line of the pressure hole on the downstream side is 8D from the rear end of the orifice plate.Among the above 5 pressure methods, the corner joint pressure method is used the most, followed by the flange pressure method. However, there is a fundamental difference in the pressure location where the main medium is gas, liquid and steam.
Post time: 21-09-21