Metering valve.

摘要

A metering valve has a one-piece bonnet (30) for reducing problems resulting from tolerance stack up. A guide portion (62) on the nose of the bonnet co-operates with a bore (20) in a valve body (12) to ensure concentric alignment between the metering pin (24) and its associated orifice (18). A pair of O-rings (72. 74) on the valve stem (26) co-operate with the bonnet bore (28) to absorb forces and substantially reduce the potential for galling and breakage of the metering pin. One (72) of the O-rings is compressed to a substantially greater extent than the other (74) to aid in achieving better alignment between the stem (26) and the bonnet (30), and to obtain a firmer feel. A handle (34) at the outer end of the valve stem (26) receives an upper portion of the valve bonnet (30).

A packing (116, Figure 4) is interposed between the handle (86) and the upper portion of the valve bonnet (30) for limiting lateral movement between the handle and the valve stem. The packing may be selectively adjusted without altering a preset deadstop position of the valve.