Traps & Filters
22Pages

Traps & Filters In This Section Technical Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-2 to 5-5 Foreline Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-6 to 5-10 MICROMAZE(R) (Absorbent Plate Elements) . . . . . . . . .5-6 Molecular Sieve Element . . . . . . . . . . . . . . . . . . . . . . . . .5-7 Metal Wool Element Traps . . . . . . . . . . . . . . . . . . . . . . . .5-8 Inline LN2 Cooled Traps . . . . . . . . . . . . . . . . . . . .5-9 to 5-10 Foreline Dust Filters . . . . . . . . . . . . . . . . . . . . . . .5-11 to F15 KF Flanged . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-11 to 5-12 Polyester Element . . . . . . . . . . . . . . . . . . . . . . .5-13 to 5-14 Fiberglass Element . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-15 External Oil Filtration Units . . . . . . . . . . . . . . . .5-16 to 5-17 Single Canister Versions . . . . . . . . . . . . . . . . . . . . . . . . .5-16 Multiple Canister Versions . . . . . . . . . . . . . . . . . . . . . . .5-17 Oil Mist Eliminators . . . . . . . . . . . . . . . . . . . . . . .5-18 to 5-21 Standard Series . . . . . . . . . . . . . . . . . . . . . . . . .5-18 to 5-19 OEM Mist Eliminators . . . . . . . . . . . . . . . . . . . . .5-20 to 5-21 OEM Filter Element Cross-Reference . . . . . . . . . . . . . . .5-22

Technical Notes ➤ Traps Overview ■ What Are Traps and Filters? In general, a trap is a device that captures gases and vapors, while a filter captures particles, chemical “smokes”, and aerosols. These distinctions imply the devices work under different pressure ranges, loosely defined as: traps operate best at 10-3 Torr or lower and filters operate best at 10-2 Torr or higher (see sidebar, Trapping and Filtering). Traps are placed in two positions: 1. Between the high-vacuum pump and the mechanical pump—foreline trap 2. In or near the chamber—system trap Filters are positioned: 1. Ahead of...

Technical Notes ➤ Traps Overview application: the porous trap and an LN2 cooled re-entry trap. While often pressed into such service, in reality, they are not ideal. Trapping process vapors is difficult. First, in contrast to low mass transfer during pump vapor backstreaming, process vapors often present gas loads large enough to overwhelm the relatively small capacity of the foreline traps. Second, large mass flows from the process imply the foreline and trap are in transitional or viscous flow regimes. The predominance of gas phase collisions in these regimes causes some fraction of vapor...

Technical Notes ➤ Filters Overview ■ Filters ■ Foreline Filters Foreline filters (often called inlet filters) are designed to stop/trap dust particles made in the vacuum process from reaching the pump. There are two basic forms. The first has a replaceable element (not unlike the air filter in a car), and the second uses a centrifugal principle to force the particles into a storage volume. Foreline Filter with Replaceable Elements As noted earlier, it is not uncommon to combine different filtration elements (or methods) in one container. An example is filtering particles with a wide range...

Technical Notes ➤ Filters Overview ■ Oil Filters Particles entering an oil-sealed rough pump may or may not chemically react but will certainly form sludge. An oil filter, primarily, removes particles to reduce wear on close-tolerance pump surfaces. Typically, filter elements trap particle sizes >0.2 microns. Activated alumina is often used to neutralize hydrous acid and Lewis acids that are part of the process exhaust gases. A few large-capacity pumps have small oil filters integrated into the pump body. But for those that do not, external oil filtration units are recommended. One or more...

^^^■S^H Company

Foreline Traps ➤ Molecular Sieve Element IN THIS SECTION ➤ Molecular Sieve Element Traps What These Traps Do • Zeolite desiccant removes hydrocarbons that backstream toward the chamber when the mechanical pump oil reaches its vapor pressure • Trap water vapor and other gases before they reach the mechanical pump and contaminate the pump oil • Can reduce the frequency of oil changes by a significant amount Design Features • Use a split-housing design for ease of maintenance and zeolite replacement • Sieve material rests in a suspended basket fabricated from perforated 304 stainless steel,...

Foreline Traps ➤ Metal Wool Element Traps ■ Replaceable Element • Rechargeable traps Metal Wool Element Traps Ideal for use in mobile/portable vacuum systems or where pumps are repeatedly cycled or systems vented. • Features an inexpensive replaceable steel wool element that is changed after oil vapor breakthrough occurs • Comes standard with copper wool filter elements (other element materials sold separately; see replaceable metal wool elements) • A foreline vapor trapping device • Feature a large surface area of metal wool • Do not need regeneration • Do not absorb moisture from the...

^^H^H Company Inline LN2 Cooled Traps ■ Inline Style (Single Fill Tube) Works in vacuum systems containing solvents, water vapor, or organic vapors. • Traps volatile materials before they can enter the mechanical pump to ruin the foreline pressure and • Traps all oil vapors before they can enter the chamber from the mechanical pump • Acts as a pump, producing lower base pressures and faster pump down • Two-piece split-housing body enables quick removal of the reservoir for cleaning without disassembling the system NOTE: 4" traps hold 0.75 liter LN2 and 6" traps hold 1.6 liters LN^ NOTE:...

Foreline Traps ➤ Inline LN2 Cooled Traps ■ LN2 Control & Transfer These flexible stainless steel hoses are vacuum insulated, conferring many advantages over normal methods of transferring LN2 from a pressurized dewar to the trap or cryogenic shroud. Vacuum Insulated Flex Hoses • Warm to the touch and will cause no freeze-burns • Conserve LN2 (see chart below) Traps & Filters Example Ordering Configuration Part No.: • Eliminate danger of frost, ice-balls, or moisture problems • Enable for fast delivery of LN2 to the receiver Part No. for vacuum hoses • Eliminate hazard of water puddles •...