User manual

Instructions for Use

General

Variable Leak Valve User Manual / 87-400-085-01 (D) 11/36

Variable Leak Valve Description

The variable leak valve includes a movable piston with an optically-

flat sapphire that meets a captured metal gasket (see the following

figure). This forms a seal completely free from friction, seizing, and

shear. The sapphire’s movement is controlled through a threaded

shaft-and-lever mechanism having a mechanical advantage of 13,000

to 1. Spring washers keep this drive mechanism constantly loaded

and eliminate the backlash usually associated with this type of

device. This provides immediate response to small movements in the

finger-controlled adjusting knobs. While some permanent

compression takes place in the gasket each time a seal is made, the

change is very slight. Return of the knob to a previous position will

result in approximately the same leak rate.

The Valve is Shipped in a Closed, Leak-Tight

Condition.

To open a leak, the knurled knobs must be turned (together) a

minimum of two full turns counterclockwise. The valve is closed by

turning the knobs (together) clockwise to the stop position against

the handle.

Figure 2

Sealing detail