T1000534_v2ErgoArm Procedure - DCC
Contents
1. 4 Lifting an Optic First decide who is the spotter the ergo arm operator and the optic handler Then go through the whole procedure first with a dummy optic if anyone has not used the ergo arm before 1 Check that the suction plate is the correct type for the kind of optic you are lifting ie the Test Mass suction plate has flats that need to line up with the Test Mass flats Check that the crash mat is situated on the ergo arm legs Make sure vacuum plate evacuating valve 14 is closed Make sure pump down air vent valve 13 is open Plug in and turn on vacuum gage wireless receiver 16 It should read 0 0 representing atmospheric pressure in 1n Hg 6 Hold the hose of the pump 18 with the fitting facing you and turn the cap 4 turn counter clock wise to insure it 1s loose 7 Place the fitting over the evacuating valve nipple 14 and turn the fitting counter clock wise viewed from above to finger tight The valve is sealed by an o ring so don t worry about it being overly tight In fact the o ring makes a good seal even if you do not tighten it at all it just takes longer 8 Turn the pump 18 on It will take about 3 minutes to pump down to 26 in Hg If the gauge 16 does not respond within 10 seconds something is wrong Usually this is because the o ring is not close enough to the optic to pull vacuum check that the o ring is touching the optic on all sides Also check the hose and valve for leaks 9 After it has reached 252. 271n Hg pressure close the vent valve 13 10 THEN shut off the pump unscrew the fitting 1 2 turn and remove the hose Make sure steps 11 and 12 are done in the right order The tank is now full of nothing 11 Unscrew the vacuum fitting on the hose 1 2 turn and remove from valve 12 If you are lifting an optic out of its optic container place the container on the crashmat This will allow the container to tilt making it easier to make full contact with the o ring and is the easiest and safest way to lift it A 13 Position the ergo arm relative to the optic using steps 14 21 as a general guide for picking up horizontal optics 14 Crank the vertical horizontal tile wheel 5 until the vacuum plate is approximately 15 horizontal and at least 10 above the plane of the optic s surface 16 Roll the Ergo Arm roughly in place using one person on each side gripping the handles 17 Loosen and turn the vertical hand crank counter clock wise to lower the carriage and vacuum plate toward the optic 18 When you are about 1 4 above the optic use the Vert Horiz Tilt 19 wheel 5 to make face of optic and vacuum plate more parallel Also unlock the LIGO 20 21 IBA 23 24 23 26 2T 5 LIGO T1000534 v2 left right guide block brakes 7 and center optic from side to side Re lock all locks when you are done positioning in a given direction to prevent sliding into the optic Unlock Horizontal positioni
3. LASER INTERFEROMETER GRAVITATIONAL WAVE OBSERVATORY LIGO LIGO Laboratory LIGO Scientific Collaboration LIGO T1000534 v2 LIGO Date 10 01 10 COC Ergo Arm Procedure for lifting large optics Mike Gerfen Margot Phelps Garilynn Billingsley Distribution of this document LIGO Scientific Collaboration This is an internal working note of the LIGO Laboratory California Institute of Technology Massachusetts Institute of Technology LIGO Project MS 18 34 LIGO Project NW22 295 1200 E California Blvd 185 Albany St Pasadena CA 91125 Cambridge MA 02139 Phone 626 395 2129 Phone 617 253 4824 Fax 626 304 9834 Fax 617 253 7014 E mail info ligo caltech edu E mail info ligo mit edu LIGO Hanford Observatory LIGO Livingston Observatory P O Box 159 P O Box 940 Richland WA 99352 Livingston LA 70754 Phone 509 372 8106 Phone 225 686 3100 Fax 509 372 8137 Fax 225 686 7189 http www ligo caltech edu LIGO LIGO T1000534 v2 1 Introduction The purpose of this document is to provide a procedure for lifting and moving large optics with the Ergo Arm This procedure uses information from Mike Gerfen s User Manual as well as notes and observations from several people during the use of this instrument compiled into a procedure format This is intended for use with the second generation ergo arm that will be used at the observatories 2 Preparing a lab area for Ergo Arm use This section explains what COC considers
4. good policy for working with the Ergo Arm and large optics It is a short list of practices learned from lab experience that keeps the optic and work area cleaner and reduces the frequency of accidents 1 Clean workspace of unnecessary clutter tools etc 2 Use 3 man system when operating the ergo arm one to orient the optic one to operate the arm and one to take the role of spotter The spotter should watch the pressure gauge keep an eye on the arm optic interface and watch for mistakes the other two people may be making This role has proven to be very valuable in practice 3 When working with a real optic wear gloves at all times 4 Wipe down dirty tools with IPA 5 Remove all pens from pockets 6 Put glasses on a lanyard 7 Remove or cover all jewelry 8 Wear gloves hairnet and a facemask when around unprotected optics Gown optional 9 Ifthe optic is coming out of its metal container wipe down the outside of its container with IPA before opening it 10 Wipe down inspection fixture with IPA 11 Wipe down any o rings that will be touching the optic with spectroscopic grade isopropanol only preferably in glass dropping bottles 3 Using the Electronic pressure Transmitter Receiver There is an electronic Omega PX921 wireless pressure transmitter 15 attached to the vacuum tank on the ergo arm The Omega receiver that 1s housed in the clear plastic box receives its signal This receiver has a black digital readout that shows the
5. has not come out of its track if it has then pop it back in Also when the ergo arm is lifted to its highest position and is being lowered back down the operator has to make sure that the wire is winding on the crank spindle correctly otherwise it can wind up the side of the spindle then drop suddenly LIGO LIGO T1000534 v2 Figure 5 Winding too far to the right it will start to wind up the right side of the arm Figure 6 Fixing the wire it should wind onto the spindle from left to right viewed this way LIGO LIGO T1000534 v2 8 Quick Checklist For people that are already accustomed to using the ergo arm this is a quick checklist when using the ergo arm For first time users go though the procedure first using a dummy optic to get used to the ergo arm 8 1 Lifting a Large Optic O Wear Gloves hairnet and facemask at the least O 3 people one operator one optic handler and one spotter O wipe down dirty tools and optics containers w isopropyl O Locate crashpad OCheck if vacuum plate matches optic test mass plate has flats O Put battery in pressure transmitter does it blink green O Remember 1 CW on handle crank raises arm 2 CWW on handle crank lowers arm 3 CW on fwd back arm goes forward 4 CCW on fwd back arm goes back O Check that the vacuum tank holds vacuum O Tighten all locks on ergo arm head before lifting optic O Watch pressure gauge when lifting If pressure begins to drop and or the alarm s
6. ics The consensus of these tests 1s that if the ergo arm s o ring lies fully on OR fully off of the dry first contact layer it will make a good seal If the o ring lies on the border between the first contact layer and glass it will not make a good seal Below is a picture of the ergo arm o ring crossing the first contact glass border this is what you want to avoid gt Figure 1 barrel and bevel of optic is on the left in the center is the o ring crossing over the FC border LIGO LIGO T1000534 v2 During this test the optic was moved from horizontal to vertical position and then back to horizontal spending 5 minutes in each position It lost a total of 0 151n Hg over 20 minutes This not nearly enough of a leak to cause an optic to fall however it was a direct result of the first contact border interfering with the o ring s seal and it is best to avoid any loss of vacuum when lifting optics The second test we did was to coat the optic s surface with first contact out to the edge and then leave it suspended in the horizontal position for a few hours During this test there was no loss of vacuum so it is possible to get a good vacuum seal with the first contact just keep in mind that the o ring cannot lie right on the border like this 6 Replacing the vacuum plates The ergo arm has three different vacuum plates one for each diameter of the core optics CPs ERMs ITMs and ETMS all use the vacuum plate that has flats
7. ng brake 4 and center optic front to back Note horizontal arm will move in the same direction as the bottom of the moving hand wheel Continue to lower carriage with hand crank 1 and reposition vert horiz Tilt wheel 5 until you have made contact with the optic Open vacuum plate evacuating valve 14 fully You should hear hissing for a couple seconds and then silence If it continues to hiss or drops more than 3 in Hg good contact is not being made with the optic s surface Watch the vacuum gauge very closely to make sure it does not lose vacuum Do this for at least 2 minutes Do not continue lifting if it loses vacuum If the alarm sounds when lifting crank down the optic until it is resting safely on a flat surface Typically the ergo arm will not drop an optic until it gets down to lt 2 1n Hg so starting around 25 in Hg gives plenty of time to crank it back down in the event you lose vacuum A hair trapped in the o ring will result in a seal that changes by about 0 25in Hg in 5 minutes If the pressure drops this fast the seal is bad and needs to be re sealed Check that all locks are tightened Move to new location Moving the optic in the horizontal position has the highest safety margin Make sure the crash pad is resting on top of the ergo arm s legs Slowly loosen the vacuum release valve Back the arm off the optic Lifting a First Contact coated optic Several tests have been done on lifting first contact coated opt
8. ounds crank the optic back down 8 2 Lowering optic 11 Transporting the optic in the horizontal position is safest O Stop as soon as optic sets down to avoid pressing on it with the ergo arm O Verify the optic is resting fully on the surface O release vacuum slowly O Keep vacuum plate and vacuum pump nozzle covered with foil when not in use LIGO LIGO T1000534 v2 9 Referenced Pictures Numbered components in pictures 1 Vertical Hand Crank 2 Vertical Hand Crank Brake 3 Horizontal positioning Wheel 4 Horizontal positioning Brake 5 Vertical Horizontal tilt wheel 6 Right Left guide block 7 Right Left guide block Brakes 8 Right Left swivel Brakes 9 Vacuum plate 10 Rotation Brake 11 Upper Vacuum hose 12 Lower vacuum hose 13 Pump down air vent valve 14 vacuum plate evacuating valve 15 wireless vacuum gauge transmitter LIGO LIGO T1000534 v2 10
9. the smallest plate goes with the R optics and the large diameter plate goes with the FM BS optics Figure 2 TM vacuum plate on left FM s on the right and R s in the back There are a couple of things to keep track of when switching out the plates To remove a plate remove two opposing screws Screw the spacers into these screwholes Figure 3 Spacers are in place and screws removed LIGO LIGO T1000534 v2 After putting in the spacers remove the other two screws The spacers keep the vacuum plate from falling off once all the screws are removed Make sure the rotation brake 10 is backed off all the way then wiggle the faceplate gently from side to side until 1t comes off Keep in mind that there are small black o rings in between the vacuum plate and the ergo arm don t knock these out of their tracks Also make sure the Teflon rotation brake does not come off there is no plate holding it on so the Teflon part can come off Grab the other vacuum plate line it up with the spacers slide it on Replace two of the screws making sure the washers are in place Remove the spacers put the other 2 screws back in Tighten all 4 screws very tight Make sure there are no spaces between the back of the plate and the ergo arm 7 Wire Crank The thick steel wire that cranks the ergo arm up can hop out of its track like this Figure 4 Wire laying to the right of its track Every time the wire becomes slack check to make sure it
10. vacuum pressure of the tank when it is plugged in Normal air pressure is 0 0in Hg and a fully evacuated tank reads around 27in Hg It is safe to lift an optic in the 24 271n Hg range When you are ready to evacuate the vacuum tank unscrew the transmitter lid and put the battery in When you put the battery in the green LED should start blinking and continue blinking If it is not blinking or if it just a solid green light the transmitter is not working properly If the LED does not light up at all the battery is probably dead although these batteries are should supposedly last for 1 year of use It takes a 42 AA battery full voltage is 3 6V The DIP switches should be set like this where 0 is off down 1 is on up AC Pe Aye pes Pere ee ee Eee LIGO LIGO T1000534 v2 When the receiver is plugged in the alarm goes off until the tank is pumped down to gt 201n Hg This alarm is in place to go off under 20in Hg Since the ergo arm will let go of the optic only after getting down around 21n Hg the alarm gives the operator plenty of time to get the optic into a safe position in the event of a leak Cranking it down to rest horizontally on the crash mat is a good idea if this happens When attaching the arm to an optic the receiver will read a drop of about 2 3in Hg for a good seal and then should stay at a constant value after this After finishing the use of the ergo arm unplug the receiver and take the battery out of the transmitter
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