Fig 640 & 660 Vent Valves

Keystone Fig 640/660 (Ventilation Valves)

Figure 640 Stainless Steel Round Vent Valve

Keystone Figure 640 Aluminum Round Vent Valve

Keystone Round and Oval Vent Valves

Tork Systems has one of the largest standing inventories of Keystone vent valves on the West Coast. With both Figure 640 and Figure 660 vent valves in stock, Tork can provide top tier quality at highly competitive prices.


  • Fig 640: 2-1/2″ to 30″
  • Fig 660: 31″-41″

Designed primarily for ventilation service where fabricated duct work is used, Keystone Figure 640/660 valves are in compliance with all requirements per BUSHIPS drawing No. 805-1749102 and 805-1749103, respectively.

Figure 660 Stainless Steel Round Vent Valve

Keystone Figure 660 Aluminum Oval Vent Valve

Keystone Figure 640 and Figure 660 valves feature standardized shaft ends and top plates for actuator interchangeability. Standard universal seat design on the Figure 640 is suitable for OD tubing, rubber lined, heavy duty and standard pipe. Round vent valve seats 14″ and larger and all oval vent valve seats are suitable for standard ventilation ducting. The seat is replaceable and serves to isolate the shaft and body parts from steam. Patented dovetail seat retention requires no bonding, simplifying seat replacement. Extra-heavy edge selection resists tearing, and eliminates need for flange gaskets.

The rounded disc and hub edge provide full concentric seating without obstructing flow and allows maximum seat life. Specially designed stainless steel disc screws allow quick disassembly and interchangeability.  Connection is positive, vibrationproof and stronger than the shaft.

Every figure Keystone vent valve is factory tested to 110% of its rating, drop-tight in both directions.

Special handle and gearbox actuators for the Figure 640/660 valves are made of aluminum. The Figure 401 handle may be used with a 2-position notch plate, with optional padlock feature. Designed for one-hand operation, the handle can be mounted in any quadrant with relation to the valve body.