66 Series Direct-Operated Regulators and Vacuum Service Equipment Figure 1. Exterior of Type 66 or 66Z Regulator Introduction Fisher™ 66 Series direct-operated pressure-reducing regulators are widely used in burner control, tank blanketing systems and other applications where precise control of low-pressure industrial gases is needed, while 66 Series direct-operated vacuum service equipment comes in both vacuum regulator and vacuum breaker constructions. These products differ in pressure capabilities and construction (Figures 1 through 4). Features   •  Sensitive Response to Pressure Changes— Minimum lockup at high as well as low inlet pressures is provided on all regulators by a balancing diaphragm that reduces unbalanced forces acting on valve plug.   •  Seat Protection without Sacrifice in Shutoff Capability—Retainer (Figure 2) of standard Type 66, 66Z or 66ZZ valve plug assembly closes against the orifice before assembly can over travel and thus over-compress O-ring.   •  Tank Blanketing Capability—Maximum sensitivity and low outlet pressure accuracy make this an ideal regulator for tank blanketing (padding) applications.   •  Accuracy—Pitot tube of Type 66, 66Z, or 66ZZ standard cast iron regulator registers body outlet pressure from point of highest velocity, creating a dynamic boost (Figure 5 or 6) that helps provide a more nearly constant downstream pressure and rapid adjustment to small demand changes.   •  Application Flexibility—Steel and stainless steel bodies are available for increased resistance to piping stresses or whenever dictated by local codes. External registration is standard or optional depending on construction for wherev

66 Series Specifications Body Sizes and End Connection Styles Construction nominal body size Standard Cast Iron Body Optional Steel Body in. Type 66, 66Z, 66ZZ or 66 vacuum regulators or breakers Maximum Allowable Inlet Pressures(1) Emergency Inlet Pressure: Type 66, 66Z, 66ZZ or 66 Series Vacuum Breakers: 25 psig / 1.72 bar positive pressure Series vacuum regulators: 8 psig or 16.3 in. 66 of mercury / 0.55 bar d vacuum Maximum Safe Pressure to Avoid Internal Parts Damage: Type 66: 10 psig / 0.69 bar Type 66Z: 5 psig / 0.34 bar Type 66ZZ: 2 psig / 0.14 bar 66 Series Vacuum Regulators or Breakers:...

66 Series Specifications (continued) Construction Materials (continued) Pressure Registration Snap Ring: Bronze Type 66, 66Z or 66ZZ: Closing Cap, and Type 66 or 66Z Adjusting Screw and Spring Seats: Zinc Flapper Valve, and Type 66ZZ or 66 Series Vacuum Regulator or Breaker Adjusting Screw, Spring Retainer and Spring Case Coupling: Brass 66 Series Vacuum Regulators or Breakers: External Orifice, Metal Seat Parts: Brass (standard) or 316 Stainless steel NACE Construction Body: Steel Upper and Lower Diaphragm Case, Sealing Diaphragm Plate, Adjusting Screw and Closing Cap: Steel Disk Retainer, Disk...

66 Series Table 1a. Outlet (Control) Pressure Ranges, 2 in. / DN 50 Body outlet (Control) pressure range In. w.c. Unless Otherwise Designated control spring information Free Length Wire Diameter Color Code Purple Stripe Orange Stripe Brown Stripe Red Stripe Black Stripe Orange Stripe Purple Stripe 0.75 to 1.5 psig 1 to 2 psig 1.5 to 3 psig 3 to 5 psig Part Number Red Stripe Unpainted Unpainted Black Stripe Brown Stripe 66 Series Vacuum Regulators or Breakers Blue Stripe Green Stripe Black Stripe 1.  1 psig / 0.07 bar minimum differential pressure required with this range. 2.  Heavy head construction...

66 Series Table 1c. Outlet (Control) Pressure Ranges, 4 in. / DN 100 Body outlet (Control) pressure range In. w.c. Unless Otherwise Designated control spring information Part Number Free Length Color Code Wire Diameter Gray Stripe Gray and White Stripe Red Stripe Green Stripe White Stripe Yellow Stripe Light Blue Stripe Pink and Blue Stripe Silver Stripe Pink Stripe ---- White Stripe 66 Series Vacuum Regulators or Breakers Black Stripe White Stripe Yellow Stripe Brown Stripe 1.  1 psig / 0.07 bar minimum differential pressure required with this range. 2.  Heavy head construction required. 3. ...

66 Series plug for blocking internal registration adjusting screw tapped boss for connecting external control line W0037_1*/IL valve plug skirt Detail of external registration construction balancing diaphragm pitot tube o-ring retainer spring retainer standard type 66 regulator with internal registration spring case extension control spring spring case coupling standard type 66Z regulator with internal registration Figure 2. Types 66, 66Z and 66ZZ Construction Details Available Configurations Constructions come standard with cast iron bodies and pitot tube style internal registration that eliminates...

CONTROL SPRING VALVE STEM VALVE SKIRT EXTERNAL CONTROL LINE SEAT RING inlet pressure outlet pressure atmospheric pressure Figure 3. Standard Steel Body Operational Schematic Principle of Operation In the cast iron Type 66 regulator, a pitot tube senses outlet pressure. In a steel Type 66 regulator, an external control line senses outlet pressure. Both pressure-sensing methods register the outlet pressure under the main diaphragm. When increased downstream demand lowers the outlet pressure, the lower pressure under the main diaphragm causes the regulator main spring and valve plug and stem assembly...

66 Series Installation A 66 Series regulator or breaker should be installed horizontally with the diaphragm casings vertical above the body. Other orientations will change the setpoint and outlet pressure range due to the weight of the internal parts. Typical installations are shown in Figures 8 through 10. To obtain the maximum flow capacities in some instances, outlet piping will have to be swaged up above the body sizes. Connection locations and dimensions are both shown in Figure 11. Overpressure Protection 66 Series pressure-reducing regulators, vacuum regulators and vacuum breakers have...