P.B./S.T. P.B./S.T.

Type P.B./S.T.

This Rotary (P.B.) Union is fitted with an elbow suitable for double flow with a stationary centre tube. This gives flow areas through the centre tube and annulus. Centre tubes are only provided if ordered. The centre tube is fixed to the Rotary (P.B.) Union end by means of a screw thread shown as dimension “O”. Flow can pass in through the centre tube and return through the annulus or be reversed.

For steam applications the centre tube is curved to reach the condensate in the bottom of the cylinder. At times the roll neck diameter to length ratio prevents a curved tube being used, in such cases we can provide a Syphon Elbow.

Type P.B./S.T. for double flow stationary centre tube

Nominal
size
A Part No.
15 (½”) G.½” 18467 – R or L
¾”-16 UNF 18467U – R or L
M22 x 1.5 18467MB – R or L
20 (¾”) G.¾” 18470 – R or L
1″-14 UNS 18470U – R or L
M30 x 1.5 18470MB – R or L
25 (1″) G.1″ 18473 – R or L
1½”-12 UNF 18473U – R or L
M35 x 1.5 18473MB – R or L
R, L depend on the direction of rotation

Rotary (P.B.) Unions – type S.T. – Dimensions

Nominal
size
B C D E F G H I J K M O Q U V
15 (½”) G.½” 13 193 130 29 16 44 68 181 G.¼” 30 G.1/8″ 12 173 38
20 (¾”) G.¾” 18 196 133 32 19 44 68 184 G.¼” 30 G.¼” 12 176 38
25 (1″) G.1″ 22 210 148 43 22 52 88 197 G.3/8″ 25 G.3/8″ 9.5 185 42
Dimensions in millimetres


‘G’ is the designation for parallel pipe threads to BS2779 and ISO 228/1