Batescrew Extreme Head Valves
Configuration

Valve configuration describes the method of attaching the valve, the type and arrangement of control mechanism, and ancillary items such as support towers.
Smaller valves, with a single screw mechanism, may be installed using any of the conventional mounting methods eg. headwall mounting, grouted, flanged, gibault type rubber-ring joiners.  The very large valves with dual screw control are usually welded directly to pipes.

SINGLE SCREW VALVES  This applies to valves up to and including 2400mm nominal bore.
Standard single screw valves, as seen here, have a control column of sufficient height to exceed the maximum water level, thus avoiding the need for a sealing gland.
They have a spigot on each side, which can be welded to a pipe, or to which flanges may be welded.  The spigots can be of unequal diameter (see dimensions B1 and B2 on the dimension sheet)  Dimensions.
Longer Control Column.  A longer column may be ordered, in order to bring the gearbox to a convenient working height.
Truss Tower.  As seen here on the left valve.
This option is available, to stabilize an extended column, if it is not practical to brace the column to another structure. 

Lower Gearbox.  The operating height of the gearbox may be made lower than normal, by having a sealing gland at the top of the body and the control screw mounted externally.  The screw is connected to the door by a stainless tube, passing through the gland.  A standard angle gearbox is mounted on a frame, at a height to accommodate thread travel.
A diagram of this arrangement, with the minimum height achievable (A9), can be seen on the dimension sheet.  Dimensions.

TWIN SCREW VALVES  This applies to valves of three metres nominal bore, and larger.
In the standard configuration, the valve body is built to a height exceeding the maximum operating head, allowing removal of the drive head assembly without overflow of water and  avoids the need for sealing glands.
The most common mounting arrangement is for the valve to be provided with a short spigot on one side of the body, for welding to an outfall pipe, the other side having a square discharge spigot.  Other arrangements are as follows:

Cylindrical spigots can be provided on both sides of the valve, for insertion within a pipeline.  These may be of unequal diameter, if required.

Headwall mounting can be provided by flanged square spigots, which are more cost-effective than conventional circular flanges.