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nEDM Full Valve Test Apparatus

nEDM Full Valve Test Apparatus. July 31, 2007 Steven Williamson (with contributions from Larry Bartoszek, Doug Beck, John Blackburn, Jan Boissevain, and Eric Thorsland). Introduction. This presentation is meant to Point out the features of the full-valve test apparatus

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nEDM Full Valve Test Apparatus

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  1. nEDM Full Valve Test Apparatus July 31, 2007 Steven Williamson (with contributions from Larry Bartoszek, Doug Beck, John Blackburn, Jan Boissevain, and Eric Thorsland) nEDM Full Valve Test Apparatus – July 31, 2007

  2. Introduction • This presentation is meant to • Point out the features of the full-valve test apparatus • Identify some of the important dimensions • Display views of the apparatus (for those without access to Inventor 10 or a compatible CAD package • List some of the assumptions, caveats, and open issues • The Inventor 10 model, from which all images are drawn is available at: http://www.npl.uiuc.edu/~jblackbu/SEW_Valve_Tester.zip • The main assembly files which depict various modes of operation are: • cryostat-dewar-assembly-V2.iam • cryostat-dewar-assembly-hydro-layout-V2.iam • cryostat-dewar-assembly-pressurizer-layout-V2.iam • cryostat-dewar-assembly-valve-test-internals-V2.iam nEDM Full Valve Test Apparatus – July 31, 2007

  3. Sources • The model is based on: • .pdf file from Janis of drawing D12-12-95A showing a typical (but smaller) dewar insert with a 1K pot • Raster image from Janis web site of a CNRD (LN2-shielded) dewar. Dimensions for the 12CNRD listed in the associated table were used. • Mechanical Desktop model created by Larry Bartoszek on June 27, 2007 during his visit to UIUC. • “Full Valve Test Issues” document and discussion with Doug Beck around July 2, 2007 • John Blackburn’s updated Inventor model of the bucket-dewar valve test apparatus dated July 7, 2007 • Steve Williamson’s Autocad model of the full vale test apparatus dated July 17, 2007 • Discussions with Eric Thorsland and John Blackburn (July 17 to July 26). • The Inventor model was produced by John Blackburn nEDM Full Valve Test Apparatus – July 31, 2007

  4. Outside View • Shown here is the outside of the dewar, rendered as transparent and as opaque, with the top flange, fittings and actuators. • While the design is based on the Janis CNRD12 dewar, the height is significantly greater than the standard unit. • The height of the dewar from floor to the top-flange seal surface is 65.53” • The OD of the dewar is 17” • The ID of the dewar is 12” nEDM Full Valve Test Apparatus – July 31, 2007

  5. Top Flange • Shown here are two views of the top flange. • The following 15 penetrations have been included: • 3 ~0.8” OD tubes which enter the LN2 volume in the dewar (presumably for fill, exhaust, and level measurement) • A central tube for valve actuation (1.5” OD, 2.75” Conflat flange (CF)) • A second “spare” large diameter (1.5” OD, 2.75” CF) port into the internal vacuum vessel (IVV) shown here with electrical connections, relief, and evacuation. • An exhaust/relief/electrical port into the LHe volume of the dewar (1.5” OD, 2.75” CF) • A 0.75” OD tube on 1” pant-leg with a 2.75” CF for exhaust of the 1K pot (shown with a T and relief valve). • A Wilson seal for a 0.5” LHe fill stinger. • An o-ring sealed rotary feed-through for control shaft for 1K pot fill valve • 6 0.5” tubes terminated with VCR fittings which extend to the the IVV. One is shown with an MDC rotary vacuum feed-through (for pressurizer or hydraulic actuator fill control). • The next transparency identifies these penetrations. nEDM Full Valve Test Apparatus – July 31, 2007

  6. 0.5” tube to IVV with VCR shown with MDC rotary feedtrhru Tube to LN2 volume 0.5” tube to IVV with VCR 0.5” tube to IVV with VCR 1K pot fill valve control 0.5” tube to IVV with VCR Extra large tube to IVV shown with (redundant) electrical, relief and exhaust fittings LHe fill stinger on Wilson seal 0.5” tube to IVV with VCR Tube to LN2 volume Central valve actuator tube, shown with G0 actuator and electrical, relief, and exhaust fittings 0.5” tube to IVV with VCR Dewar LHe exhaust/relief Top Flange 1K pot exhaust/relief Tube to LN2 volume nEDM Full Valve Test Apparatus – July 31, 2007

  7. Notes on top flange • The six 0.5” tubes to the IVV will be used as follows: • Valve fill tube • Valve exhaust tube • Hydraulic actuator fill tube • Housing for 0.25” shaft from rotary vacuum feed-through for manual actuation of the pressurizer or the hydraulic actuator isolation valve. • The two remaining tubes are spares. • The 0.5” diameter of these tubes may be too large (i.e. the heat load may be too big). • Tubes are shown welded directly into the top flange. Janis uses “pant-leg” connections in their dewar insert in some cases. That would be fine. • The bolts for connection of the top flange to the dewar are not shown. • The details of fittings for the connections to the LN2 volume are not shown. Those connections are shown as tubes projecting from the volume through the top flange. • Top flange lifting eye bolts are not shown (three eye bolts should be fastened to the top flange) • The rotary feed-through (MDC670000) on top flange is only an outline taken from the MDC catalog (no internal details). nEDM Full Valve Test Apparatus – July 31, 2007

  8. Bellows and 2.75” CF on large tubes 1” VCR on IVV evac. line (no bellows) Bellows Heat shield Below the Top Flange • This picture shows the region below the top flange. • To keep options open, all tubes to the IVV are detachable. • All but three of the tubes have bellows to avoid over-constraining the assembly and making installation of the tubes difficult (or impossible). • It has been suggested that all of the bellows be placed in-line (as was done with the 0.5” tubes) rather than welded to the top flange (as was done with the larger tubes). nEDM Full Valve Test Apparatus – July 31, 2007

  9. A view from below of the heat shields of the valve-seat tester (a.k.a. bucket dewar insert) showing their split and slotted design. Below the Top Flange • The distance between the top flange and the IVV, and the positions of the heat shields are taken from the Janis insert drawing. • The support of the heat shields is not shown. • The heat shields must be “removable”. One way to do this would be to split them in half and use slotted holes for the tubes as was done in the valve seat tester (see below) • No clearance holes have been provided for an LHe level sensor in the heat shields (and no level sensor is shown). nEDM Full Valve Test Apparatus – July 31, 2007

  10. Internal Vacuum Vessel (IVV) • These pictures show the IVV (rendered as solid and as transparent). • The IVV internal dimensions are: • height: 36.87” • diameter: 9.36” • The top flange has an indium seal and is fastened with 12 ¼-20 bolts. nEDM Full Valve Test Apparatus – July 31, 2007

  11. IVV Top Flange • Here are some pictures of the IVV top flange. • Penetrations into the IVV all have pant legs to extend length of tube connecting 4K to 1K. • Connections between tubes from the dewar top flange and the IVV top flange are all welded except the large-diameter tubes which are shown connected with 1.33” CF flanges. It might be better to use 2.75” CF flanges there to match flanges on the dewar top flange. • The top flange supports the 1K pot which is fed from the LHe reservoir via a valve on the top flange (shaft connecting valve is not shown). • The dimensions of the 1K pot and its exhaust tube are taken from the Janis insert drawing – but may need to be modified if cooling power is not sufficient. • Three copper anchors provide thermal links to 4K. • 12 ¼-20 blind tapped holes are provided to be used to support parts within the IVV. nEDM Full Valve Test Apparatus – July 31, 2007

  12. More notes on the IVV • The connection between the copper anchors and the stainless steel top flange must be vacuum tight. We assume they are brazed in place. • A IVV top flange clearance hole for an LHe level sensor is not shown (nor is the level sensor) • The 1K pot inlet valve is only an outline (taken from the Janis insert drawing). Neither internal details, nor the method of connecting to the IVV top plate, are included in the model. • The Janis 1K pot is intended to be used with the "sample" attached directly to the copper bottom plate (see ring of holes). We will need to attach our apparatus with “heat links”. Is there a better way to make this connection that should be designed in? nEDM Full Valve Test Apparatus – July 31, 2007

  13. Actuator shaft entry Secondary seal here when valve is open Bellows shield sleeve Secondary seal here when valve is closed Valve body Outlet Inlet Primary seal The Valve • The valve, included in the model and pictured to the right and in images below, is the last design from Jan Boissevain. This valve: • Does not include our latest design for the valve seat and boot. • Employs Kapton gaskets to seal parts assumed to be made of Torlon or Vespel. • Uses 3 beryllium-copper bellows which are hidden from the fluid by a telescoping sleeve. • Seals both in the fully open and fully closed positions in a way which completely isolates the bellows. • The connection from the actuators to the valve is not included in the model. • Larry Bartoszek will produce the final valve design, which will (probably) be fabricated at UIUC. nEDM Full Valve Test Apparatus – July 31, 2007

  14. Test Modes • We anticipate (at least) three modes of operation of the full valve test apparatus. These are pictured in the next few slides. • Normal valve seal integrity/exercise test • Pressurizer test • “Hydraulic” actuator test. • The size of the IVV is driven by the dimensions of the hydraulic actuator hardware. nEDM Full Valve Test Apparatus – July 31, 2007

  15. Inlet Line Exhaust Line Normal Valve Test Mode • This mode of testing is meant to exercise the valve under more-or-less normal operating conditions. • Vacuum outside the valve • LHe II controlled by valve • The normal test procedure will be: • Evacuate valve inlet and outlet. • Cycle valve some number of times. • Close valve. • Introduce gaseous helium on inlet side of valve while monitoring pressure with room-temperature baratron. • When pressure indicates LHe II is present, measure the leak rate with a helium leak detector. • The picture at the right shows the assembly within the IVV, mounted on the IVV top flange for this mode. • Liberal use has been made of VCR fittings on the inlet and exhaust line to allow parts to be re-used for other test modes. • The inlet tube diameter is chosen to be small to reduce volume of LHe II. The exhaust line may need to be bigger to improve conductance. nEDM Full Valve Test Apparatus – July 31, 2007

  16. Pressurizer Test Mode • Pressurizer test mode provides a means of raising the pressure on the inlet side of the valve to 1 atm. • This is done by extending a (stainless steel) bellows using a screw mechanism driven by the rotary feed-through shaft. • LHe II on the outside of the bellows is compressed to 1 atm by a change of total volume on the inlet side of the valve of about 1.1%. • The pressurizer in the model is about the right size but internal details are absent. • Larry Bartoszek will design the pressurizer assembly. • The pressure of the pressurized LHe II must be measured over time to measure the leak rate. • The exact method of performing this measurement must be defined. • One concept is to use a calibrated diaphram capacitance manometer. • The pressure measuring device in the model is a “place holder”. It has no internal detail. • Similar hardware can be used to pressurize the outlet side of the valve. nEDM Full Valve Test Apparatus – July 31, 2007

  17. Shaft from rotary feed-through actuates pressurizer Manometer Exhaust Line Pressurizer Inlet Line Pressurizer Test Mode • A typical procedure for performing the pressurizer test will be: • Open the valve and evacuate pressurizer, manometer, and valve from the exhaust port of the valve • With valve open, introduce gaseous helium from the exhaust side of the valve • Introduce sufficient helium to fill the valve and all plumbing on the inlet side of the valve with LHe II. • Possibly monitor temperature along fill line to watch for completion of filling process • Close valve • Extend pressurizer bellows to increase pressure to 1 atm on inlet side of valve. • Monitor pressure over time to determine leak rate. nEDM Full Valve Test Apparatus – July 31, 2007

  18. “Hydraulic” actuator Test Mode • In order to provide the closing force to valves for which there is not a simple path accessible to a mechanical actuator, it has been suggested that we could use a “hydraulic” actuator employing LHe II as the hydraulic fluid. • The hydraulic actuator test mode will test a prototype of such an actuator. • The entire actuator will be operated at 1.4K – though in another arrangement, part or all of the actuator could be moved to the 4K portion of the dewar. Whether or not there is space in the 4K volume for this needs to be determined. • The hydraulic actuator employs two large-diameter beryllium-copper bellows, one to compress LHe II and the other, connected to the valve, to react to the compression. • The hydraulic fluid will be on the outside of the bellows (extending the bellows compresses the fluid) – this avoids the “squirm” problem associated with compressed bellows. • The size of the bellows assemblies is chosen to • Allow a closing force of 200 lbs • Maintain a differential pressure of no more than 1 atm across the bellows • Not exceed the allowed extension per segment for a 10000 cycle life time. • Helium is introduced into the hydraulic fluid volume via a valve which is actuated via a shaft from the rotary feed-through. This valve must be leak-tight with LHe II. The drawing shows a standard Swagelock valve. This valve will be tested using the bucket-dewar test set-up. • Because the hydraulic bellows and plumbing will contain a significant amount of liquid and because there is no simple way to provide a relief valve, this plumbing may need a burst disk to allow emergency relief into the IVV and subsequent relief via the IVV relief valve. • The model contains no internal detail for the bellows assemblies (in the model, they are just “space-holders”). nEDM Full Valve Test Apparatus – July 31, 2007

  19. Hydraulic fill valve Hydraulic fill line Upper bellows assembly Hydraulic line Support spacers (3) Lower bellows assembly Exhaust line Inlet line “Hydraulic” actuator Test Mode • A typical test procedure will be as follows: • Evacuate the hydraulic fluid volume (hydraulic fill valve open) • Move mechanical actuator for upper bellows to set bellows at its maximum length. The lower bellows will be at its relaxed minimum length. This should correspond to the open position for the valve. (It may be necessary to mount the valve the lower bellows to meet this requirement.) • Introduce sufficient helium to fill the hydraulic fluid volume with LHe II. • Possibly monitor temperature along fill line to watch for completion of filling process • Close the hydraulic fill valve. • Evacuate valve inlet and outlet. • Close the valve by extending the upper bellows. • Introduce gaseous helium on inlet side of valve while monitoring pressure with room-temperature baratron. • When pressure indicates LHe II is present, measure the leak rate with a helium leak detector. nEDM Full Valve Test Apparatus – July 31, 2007

  20. Concluding Notes • It is our hope that Janis can build: • The LN2 shielded dewar • The Dewar top flange and all parts welded to it • The IVV top flange and all parts welded to it (including the IVV) • The IVV vacuum can • We are concerned about the heat load to the 1K pot and how heat will be transferred from the large thermal mass of the valve and other objects in the IVV. • We need to calculate the heat load. • We need to calculate the cooling power of the 1K pot. • We need to understand the thermal links to the objects in the IVV and estimate cooling time. • At this point the model contains many assumptions, guesses, and place-holders – all of which need to be firmed up and all of which are open to change. nEDM Full Valve Test Apparatus – July 31, 2007

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