Presentation on theme: "EDM Collaboration Meeting, October 5-7, 2006 Valve R&D Steve Williamson UIUC."— Presentation transcript:
EDM Collaboration Meeting, October 5-7, 2006 Valve R&D Steve Williamson UIUC
EDM Collaboration Meeting, October 5-7, 2006 Valve R&D Questions Can we make a valve seat/stem that seals, and meets our other specs, using plastic components? What leak rate can we achieve? What seating force is required? How does this depend on the number of open/close cycles? How reliable is the bellows after repeated cycling at low temperature (Teflon?)? What can be learned by making and testing a complete prototype valve and actuator? Heat load? Reliability? Manufacturing techniques? Is the LHe hydraulic actuator for V1 realistic? What is the real cost of valves and actuators?
EDM Collaboration Meeting, October 5-7, 2006 Test Plan: 2 Test Set-ups Bucket dewar test(s) of valve components Verify that valve seat/stem material can sufficiently seal LHe II Determine required seating force Test seal for many cycles Test bellows for many cycles Test LHe “hydraulic” actuator concept (?) Custom dewar for test of complete valve Test complete prototype valve under realistic conditions (vacuum outside, LHE II inside) Test realistic mechanical actuator mechanism Test plumbing interconnect concepts
EDM Collaboration Meeting, October 5-7, 2006 Some Planning Assumptions Tests at 2 K are sufficient to characterize valve at 0.5 K Dewars Use borrowed bucket dewar. Build new dewar for full valve test. Tests will be performed at UIUC 5 short tests (100 l LHe/test) + 2 long tests with bucket dewar (300 l LHe/test) 5 tests with complete valve test system (200 l LHe/test) Engineering will be carried out by Bartoszek Engineering.
EDM Collaboration Meeting, October 5-7, 2006 Bucket Dewar Tests Dewar has been borrowed: 4.5” throat 54.8” deep (18” G10, 36.8” Al) Performed “Commercial Valve Test” to commission dewar and test instrumentation. Design complete for Valve seal test insert 1 st shot at valve seat
EDM Collaboration Meeting, October 5-7, 2006 Commercial Valve Test Immerse commercial valve in LHe Pump on LHe to reduce temperature below -point. Measure valve temperature, pressure above LHe, LHe level, pressure in valve line. Try to deduce leak rate S = 100 l/s C = 3 l/s C = 0.02 l/s (1/4 in. He II 1/4 in. Nupro bellows seal valve “hand tightened” P valve P dewar (P dewar at -point is 38 Torr)
EDM Collaboration Meeting, October 5-7, 2006 Commercial Valve Test Results Effective pump speed is limited by the ¼” line to valve Preliminary estimate for valve leak rate is 2x10 -6 Torr-l/s (1x mol/s) Suppose V3 leaks at same rate. Compressibility of He II at 0.5 K J. Brooks & R. Donnelly, J. Phys. Chem. Ref. Data 6 (77) 51 Loss of He from fixed measurement cell volume (V = 10 l) reduces He pressure In 10 4 s, cells lose ~0.2% of pressure (1 atm)
EDM Collaboration Meeting, October 5-7, 2006 Valve Seat Test Insert Valve actuator Vacuum/motion feed-through Copper shields Gas Handling Circuit for valve seat testing DGH 8/13/06 to helium gas source to vacuum pump to vacuum pump to leak detector Baratron 1Baratron 2 Valve being tested Liquid helium level This is the tube that the actuator goes through This volume should be as small as possible to reduce evacuation and filling time Valve seat assembly Supply tube Exhaust/actuator tube LHe level sensor
EDM Collaboration Meeting, October 5-7, 2006 Valve Test Seat Assembly Torlon 5030 outer wall and seat Torlon 5030 gasket clamp Kapton gasket Torlon 5030 piston (but initially acrylic or aluminum)
EDM Collaboration Meeting, October 5-7, 2006 Actuator for Valve Test Borrowed spare from G 0 9/16” stroke Once closed, can deliver up to 250 lbs closing force. Computer controllable Position (and closing pressure) read out with linear pot.
EDM Collaboration Meeting, October 5-7, 2006 Bucket Dewar Test Status Design complete, 2-D manufacturing drawings still to be done (2 weeks) Bucket dewar in hand, tested Actuator in hand, tested Torlon 5030 bushing and disk in hand Other items on order (2 nd baratron, bellows, Torlon 5030 piston material) Completion of insert by end of Nov. (5-week delivery for motion feed-through bellows) Tests through January.
EDM Collaboration Meeting, October 5-7, 2006 Costs: Bucket Dewar Tests Fairly well defined Many items already purchased (or prices available). Top flange plumbing$1, Instrumentation$1, Valve material$1, Bellows material (includes Teflon bellows)$3, Liquid Helium (1200 l)$4, Engineering (5 days, 38 drawings)$8, Contingency (20%)$4, Total$25, Bucket Dewar Test
EDM Collaboration Meeting, October 5-7, 2006 Complete Valve Test Test complete prototype valve under realistic conditions Vacuum outside, LHe II inside Realistic mechanical actuation of valve Strategies: Build vacuum vessel and 1.4 K refrigeration (borrow the vacuum vessel?) Procure larger bucket dewar, forego requirement of vacuum outside. Tests: Close valve, LHe “upstream; evacuate “downstream”; and measure leak rate. LHe up and down stream; close valve; pressurize downstream; measure differential pressure over time. Interconnect test: LHe inside; measure leak to vessel vacuum.
EDM Collaboration Meeting, October 5-7, 2006 Dewar for Complete Valve Test Vacuum vessel 1-2’ diameter, 3-4’ high LN2 thermal shield (probably annular reservoir) Top plate must provide: LN2 supply, relief LHe supply, relief Pump for LHe reservoir Gaseous He supply Pump/leak detector port on downstream side of valve Motion feedthrough for valve Possibly motion feedthrough for pressurization. Design at very preliminary stage.
EDM Collaboration Meeting, October 5-7, 2006 Possible Setup for Complete Valve Test LN 2 LHe In LHe Pump He In To Leak Detector LHe Reservoir 1K Pot Test Valve Actu- ator Heat Link
EDM Collaboration Meeting, October 5-7, 2006 Valve Concept Use Torlon 5030 (30% glass loaded) for strength. Seal on flat annular surface, not sharp edge (Robert Michniak, Thesis, John Doyle advisor, 2004). Use sliding sleeve to “hide” bellows from 3 He Use commercial metallic bellows Make seal using trapped Kapton gasket. Actuate from below (mechanical linkage) Injection Molded Torlon 5030 Valve Body Commercial Bellows Torlon Piston Torlon Sleeve Actuator Kapton Gasket V6 Valves on Purifier
EDM Collaboration Meeting, October 5-7, 2006 Status of Complete Valve Test Finalize plans for complete valve test apparatus. Design dewar/topflange – end of Dec. Design valve and actuator for test – end of Feb. (depends on results of bucket-dewar test). Aim for first prototype valve in spring. Perform first test in June.
EDM Collaboration Meeting, October 5-7, 2006 Costs: Complete Valve Test Much less certain (50% contingency) Based on costs in CD1 – we will be building a real valve. Does not include hydraulic actuator ($30k) Engineering (16 days, 46 drawings)$14, Valve body/seat/stem$10, Mechanical actuator$10, Top flange plumbing$2, Vacuum vessel, internal volumes/plumbing $8, Liquid Helium (1000 l)$3, Contingency (50%)$9, Total$58,129.68
EDM Collaboration Meeting, October 5-7, 2006 Summary Design of bucket dewar test is complete; procurement is underway. Detailed concept for complete valve test is still in progress. Aiming for valve seat test in December and complete valve test in spring. Cost estimate comes to around $80k (only $40k allocated in FY07 R&D budget).