Port plate or cone — which does my liquid ring pump have, and why does it matter?
Flat-port machines take a port plate: 2BE, 2BV, NEV2, SK and SX. Cone machines take a cone: AT, ATTC, TC, CL and 2SK. They do the same job — carry the suction and discharge openings and set the timing of when each cell opens — but they wear differently and, crucially, only one of them can be adjusted to take up that wear.
That difference decides your repair route. A cone is positioned axially, so as the porting face wears you can move the cone in and restore the clearance to the impeller. Performance comes back without buying the porting part. A flat port plate has no such adjustment: once the face has worn, the axial gap is what it is, and the plate is replaced.
So before quoting either part we ask how much axial adjustment is left on a cone machine. Customers are often surprised that the answer to a vacuum complaint is a shim and an afternoon rather than a casting. We would rather tell you that, because the machine that comes back a year later with a genuine cone failure is worth more to us than one part sold today.
How the wear shows up is the same on both, and it is quiet. The face wears, gas leaks internally from the discharge side back to the suction side, and ultimate pressure degrades with no change in noise and no change in motor current. Plants chase an external leak that is not there. Blank the inlet, measure the pump's own ultimate pressure, and compare with the manual before looking anywhere else.
Send us the pump model and serial number, the porting face thickness measured at three points, a photograph of the port openings taken flat-on, and on a cone machine how much take-up is left. We cast in HT250 gray iron, 304, 316 and duplex 2205 and we check the profile against the original drawing before quoting; if it does not match, we say so.