I've seen requirements as high as 15 Torr or so for some types but 75 to 100 microns is probably more typical for this model. If you have any concerns relating to where by and how to use cross body bag straw, you can call us at our web site. The system consists of: - Pfeiffer model DUO-1.5A two stage rotary vane roughing pump (1.5 m3/hour, 25 l/m, 0.88 cfm, ultimate vacuum better than 6.6x10-4 Torr. I have had a very bedraggled Varian RG-31X combined TC and ion gauge controller for awhile (pulled from the trash of course) but that's perhaps a bit too old even for me (vacuum tube based). As normally configured, the controller powers up both the mechanical and turbo pumps at the same time so at the very least, no damage would result from running at higher than spec'd foreline pressure. For example, a microcrack in the turbine motor rotor or elsewhere in the foreline section of the turbo pump that traps enough air when at 1 atm to slowly outgas during pump down. But if left for awhile at 1 atm, it will have to go through the long drawn out pump down cycle again. See the section: Disassembling and Inspecting a Pfeiffer Duo 1.5A Rotary Vane Vacuum Pump. Since the foreline pressure is higher than what might be optimal using a two-stage mechanical pump, the final vacuum might not reach the turbo pump's 10-8 Torr (with Viton seals) rating.


I disconnected the turbo pump outlet from the foreline and put the DV-6M there to confirm that the pump was working fine. A high foreline pressure will directly affect the ultimate partial pressure of low molecular weight gases like hydrogen and helium due to their relatively poor compression ratio. Also see: A Simple Medium Vacuum System for some additional ideas on a low cost approach to a setup that may be adequate for laser construction. So, of course, both the CVT-16 and NV-8B had to be tweaked a bit using their CAL pots since this is the first time I've had a decent vacuum to test them! A magnetic closure makes this bag a bit more secure than the standard shoulder tote and the zip closure inside is the ideal secure location for cards and keys. Reassembly went smoothly though interpreting some of my hand written wiring notes was a bit of a challenge.


As far as I can tell, the turbo pump is working fine despite the antique lubricating oil. My initial assumption was contamination inside the turbo pump and elsewhere from just sitting around for several years in the corner of a lab without as far as I can tell, even a dust cover for protection. If there's a way to rinse the inside of the turbo pump with alcohol or some other solvent without requiring replacement of the lubrication oil I might try that eventually. You might want to write your address on there as well to compare later with students across the school or world. For sturdiness, students may want to loop two wires and bend the wire on the other side inwards as well to look like an O with a belt on. Because of this fact, we often simply think of gravity as some property of very massive objects like planets and stars. DVD has made movies accessible to everyone, not just reclusive movie stars. Search for anything about movies at The Internet Movie Database. 11.) Gingerbread Word Search (1-3) Student looks at the word bank and then finds the word in the puzzle. I then installed a DV-6M (1 to 1,000 microns) and DV-8M (0.1 to 10 microns).


One even had a 1/8" NPT tapped hole already there into which I installed a manifold with three 1/8" NPT tapped holes for up to 3 thermocouple gauge sensors. Poke a hole on the top with a straw. The paper mach&eacute is applied in two layers or more on the balloon, leaving a small hole at the top for the balloon to come out and for the paper clip/string to be attached. They come in a box and are made by Pepridge Farms. Both these pumps are considered obsolete by Pfeiffer but the Duo 1.5A should be usable unless some catastrophic failure occurs and parts aren't available. Initially, I disassembled this system and used only the Duo 1.5A for various tests of vacuum gauges and other assorted stuff. Powering up the Duo 1.5A and TC gauges, the system initially would barely go down to 500 microns. No change. But I did notice that the pressure was inching down (or perhaps, more correctly microning down!), just very slowly. Scratch for Arduino Makes Programing the Arduino More Visual: Windows/Mac/Linux: Programming an Arduino isn’t especially difficult, but if you’re looking for a more visual method, Scratch for Arduino (S4A) uses MIT’s Scratch as a groundwork for teaching kids (or beginners) how to program an Arduino.