2 EATONAerospace Group TF100-76C June 2013 Design Concepts Eaton’s Carter product line includes several Hose End Control Valves (HECVs) which provide pressure limitation at the outlet to protect the aircraft while refueling. Several different pressure settings are available to tailor the control system to the customer’s requirements. The resultant control pressure curve is flat with little “droop” in pressure up to 300 USgpm (1135 l/min). Downstream surge pressure generated as a result of a rapid rise in downstream pressure (aircraft valve closure) is limited to 75 psi (5.17 bar). Outlets are available to mate the HECV to any Eaton or Whittaker brand nozzle. Threaded inlet and outlet adapter fittings are also available for alternative installations away from a nozzle. A variety of inlet fittings are available to mate industry standard hose connections. Eaton’s Carter product line offers three basic HECVs – Models 60129-1, 44646 and 47013. All three are for use on underwing refueling nozzles and one, Model 60129-1, may be used for linemounted applications. Features yy Lightweight yy Low pressure drop — see curve on page 4 yy Direct spring acting yy Three pressure settings available (see Ordering Data on page 3 for details) yy Downstream surge pressure control — 75 psi (5.17 bar) max yy Fail safe design yy Model 60129-1 replaces older Model 40680 (part number change only) yy Mechanical blockout device, part number 61656 for system test and defueling now available — no connection to fuel pressure required Operation A hose end control valve is a direct spring-loaded piston device that limits pressure sensed at its outlet (hence at the inlet of the nozzle, since the HECV is mounted on the inlet to the nozzle). The HECV is designed to react to changes of outlet pressure to hold a relatively constant pressure with adequate inlet pressure. Pressure limiting is a function of the spring that loads the piston or poppet. In addition to limiting the maximum pressure at its outlet during flow conditions, the HECV is designed to also limit surge pressures caused by aircraft (downstream) valve closures. Lockup pressure (downstream pressure trapped between a closed HECV and a closed downstream system) is also limited. The highest pressure limit controlled by the HECV will be apparent as the flow rate decreases from a maximum flow condition and as the aircraft tank valves begin to close. As in all controlling devices, the HECV requires a back pressure (system pressure drop) to perform properly. If the downstream pressure is too low, or if the upstream pressure is too low, the HECV will simply stroke fully open and there will be no control. This is quite apparent at the higher flows into an empty aircraft. The HECV only controls when the downstream pressure becomes within the range of its control. Typical Characteristics yy Surge pressure control — 75 psi (5.17 bar) maximum with 0.5 second valve closure minimum yy Lock up pressure — 10 psi (0.689 bar) maximum over spring setting yy Pressure limitation — 5 psi (0.345 bar) over spring setting with inlet pressure up to 100 psi (6.895 bar) yy Hysteresis (difference in pressure limits between increasing and decreasing flow rates) — pressure limits with decreasing flow rates will normally be slightly greater than for increasing flow rates yy Defueling is possible through unit, however a block out device required to maintain maximum flow. Block out device is also recommended if system secondary control valve is to be checked. Use Eaton part number 61656 Block Out Device (see “Special Tools” brochure [TF100-116] for details). Model 44646 Model 60129-1 (Shown with quick disconnect) Model 47013
RkJQdWJsaXNoZXIy NDE1MjE4