Baker Hughes Safety Relief Valves 1900/1900 DM Series

The Cryodisc must be replaced if: - Seat defects and damage cannot be lapped out without reducing the A dimension below those listed in Table 7 (see Figure 34).

- ATTENTION! The A dimension on orifice D through H of the thermal lip disc is difficult to measure.

- If the .006" (0.15 mm) minimum thickness of the thermal lip cannot be measured, replace the Thermodisc.

- The A dimension on orifice D through H of the cryogenic disc is also difficult to measure.

- If the .008" (0.19 mm) (D, E, F orifice), .009" (0.23 mm) (G orifice), or .011" (0.27 mm) (H orifice) minimum thickness of the cryogenic disc lip cannot be measured, replace the Cryodisc.

Nozzle should be replaced if: - Dimension from seat to first thread, after re-machining and lapping, is less than D min. (see Tables 3)

- Threads are damaged from pitting and/or corrosion

- Top of flange and intersecting surface are damaged from galling and/or tearing

- Seat width is outside specification and cannot be reestablished per Nozzle Dimensions in Table 3a & 3c (see Tables 3a, 3b or 3c).

- The standard 1900 Series disc can be machined until the N dimension is reduced to its minimum size (see Table 5).

- The T dimension is provided to ensure the disc has not been machined beyond its limits.

- If re-machining reduces the thickness of the disc (T min.), the entire disc holder assembly drops with respect to the seating plane of the nozzle.

- This creates a significant change in the huddle chamber configuration and results in significantly more simmer before opening.;

- Using a measuring magnifying glass (see Lapped Nozzle Seat Widths), determine whether the seating surface must be machined before lapping.

- If the seat can be lapped flat without exceeding the required seat width (see Tables 1a, 1b or 1c), it does not require machining.

- To reduce the seat width, the 5º angle surface must be machined and all seat dimensions need to be verified, and reestablished if necessary.

- The nozzle must be replaced if the D dimension is reduced below the minimum (see Tables 3).

- ATTENTION! Flange thickness changes the center-to-face dimension. Ensure the minimum dimension for orifice D through P is .656" (16.67 mm), and for Q through W is .797" (20.24 mm).;

Replace the guide (9) if: - Visible galling is present on the inside guiding surface

Gasket seating areas are pitted and cause the valve to leak between the bonnet (11) and base (1).

- The guide (9) type varies depending on the valve type: O-ring valve, bellows valve, or standard valve.

- Inspect the guide as follows: Find the correct valve orifice size and disc holder (8) measurements (see Table 9)

- Measure the barrel portion of the disc holder and compare it to the nominal measurement on Table 6 to determine the maximum allowable clearance between the disc holder and the guide

- Replace the guide and disc holder if the clearance between the inner diameter (I.D) and the guide and/or the outer diameter (O.D) of the disc holder is not within the clearance dimensions.;