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en:construction:hotte_a_flux_laminaire [2013/04/23 14:22] ph [Laminar flow hood] |
en:construction:hotte_a_flux_laminaire [2018/06/27 15:20] |
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- | <wrap lo>« Air can be described as a sea of invisible micro-organisms, | ||
- | <tab> | ||
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- | ====== Laminar flow hood ====== | ||
- | The flow hood is a sterile air blower. The particles of the air are separated by a pre-filter and a HEPA filter. This results in almost pure air, separated at 99.97% from particles greater than 0.3 µm. This clean air exerts a positive pressure on the work plan, allowing to easily produce axenic cultures. | ||
- | ====== Prototype 1 & 2 ====== | ||
- | The first prototype met the expectations, | ||
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- | <WRAP centeralign> | ||
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- | <WRAP centeralign> | ||
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- | ===== Improvements ===== | ||
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- | Structure & aesthetics: | ||
- | * The fan replaces the legs and reduces the total height. | ||
- | * The pre-filters are placed facing the air entry of the fan. | ||
- | * The pre-filters are more accessible for cleaning. | ||
- | * The mounting depth of the pre-filters is doubled. | ||
- | * The cover of the pre-filters and the lamp cover are removed. | ||
- | * The depth of the air chamber is reduced. | ||
- | * The internal shelves are made of glass. | ||
- | * The structure requires less wood (lighter, more compact, less expensive). | ||
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- | Electronic Components: | ||
- | * Lighting with a prefabricated LED strip. More uniform, requires less wiring. | ||
- | * Transformer 12V 3A, instead of 12V 1A. | ||
- | * Grouped switches with a more intuitive utilization. | ||
- | * The magetic stirrers use two magnets rather than one (magnetic fields stronger). | ||
- | * The stirrers engines are replaced by 200rpm 12V 0.5A DC motors. They are stronger (can shake 2.8 L), and no longer need dimmer. | ||
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- | ====== Instructions ====== | ||
- | ===== Materials and assembly ===== | ||
- | **Plywood** | ||
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- | Choose select quality plywood. On one side, the holes left by the nodes are filled and wood is sanded. For the interior of the hood body, especially in the work area, cleaning will be easier. This prevents the accumulation of particles in the cracks. | ||
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- | **Primer & Paint** | ||
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- | Before cutting, paint both sides of the plywood. First clean the dust with a damp cloth, and when the wood is dry, apply a primer. A primer before the first coat of paint provides better grip and faster drying, preventing it from entering the wood. | ||
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- | Then give two to three coats of white epoxy paint. Although rather toxic, it is durable and easy to clean. Use gloves to protect your skin and apply the paint in a well ventilated area. Use a grease to clean your skin if necessary. Between layers, wrap the paint brush and the roller into plastic wrap and store them in a cool place. | ||
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- | **Centrifugal fan (" | ||
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- | The chosen model is the most powerful of Fasco in this category. If you choose another fan, make sure that its strength allows enough airflow despite the strong resistance exerted by the static pressure of the HEPA filter. You will probably have to do weld a custom bracket[(: | ||
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- | **Assembly** | ||
- | * When possible, plan a 1/8" space between each parts to compensate for the width of the saw cut. | ||
- | * (optional) Pre-assemble all pieces with a air nailer. | ||
- | * To avoid cracking of the plywood, pre-drill the screw holes with a bit of a smaller diameter. | ||
- | * Seal well all the internal parts of the hood by drawing a silicone seal. The junction between the two parts (filter and engine), and the periphery of the prefilters are sealed with packing tape, much easier to remove than silicone. Each pre-filter is individually sealed to the support. | ||
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- | < | ||
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- | **Tools needed** | ||
- | * Painting set (tarp, tray, roller, paint brush) | ||
- | * Circular saw | ||
- | * Jigsaw | ||
- | * Drill & bits (3/32 ", 5/8", 1 ½ ") | ||
- | * Caulking gun | ||
- | * Glue gun | ||
- | * Soldering iron | ||
- | * Measuring tape, screwdriver, | ||
- | * (optional) Pliers, wire stripper, hot air gun, crimping tool, air nailer | ||
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- | ===== Magnetic stirrers ===== | ||
- | <WRAP column 250px>< | ||
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- | * Align SF to the center of DF and tighten with clamps. Screw the two pieces together and remove the clamps. As shown, align the two SFa on DF, place the clamps, screw them, then remove the clamps. SF, DF and SFa 1-2 are now linked in a single piece. | ||
- | * Drill 1 1/2" holes through the thickness of SF and 5/8" holes through the thickness of DF+SFa+SFa. | ||
- | * Add the legs SFb and SFc, then prepare the stirrers; | ||
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- | * Pick up the magnets from an old hard drive. You will probably need a special screwdriver (torx). Each magnet is mounted on a metal plate. To recover it, bend the plate in the opposite direction to the magnet. | ||
- | * Join two magnets together, then preheat the magnets and the coupler (with a hot air gun or a bain-marie...). Meanwhile, preheat a hot glue gun. | ||
- | * Put some glue on the coupler and attach it to the magnets, well centered. Leave to dry. | ||
- | * Place the assembly on a motor, then secure the coupler by tightening the screw against the shaft. | ||
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- | * Place the motors into the previously drilled holes. | ||
- | * Solder the wires to the poles of the motor, as shown in the [[en: | ||
- | * In order to keep a space of 1/16" between the magnets and the surface of SF, place a cardboard piece of 1/16" thick on a straight board, and push it against the magnets. | ||
- | * Place a piece of electrical tape onto the wire end of the motors and secure it with hot glue. | ||
- | * Solder the wires to the 6-pin female plug and insulate the connections. | ||
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- | < | ||
- | ===== Maintenance ===== | ||
- | **Cleaning** | ||
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- | Before each use, the internal surfaces of the work area should be cleaned with 70% isopropyl alcohol. The " | ||
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- | **Lubrication** | ||
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- | The motor should be oiled once a year with a suitable lubricant. With a screwdriver, | ||
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- | {{: | ||
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- | ====== Plans cuts ====== | ||
- | Each plan represent a sheet of plywood 4 'x 8' x 3/4 ". | ||
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- | The hood is assembled in two modules. The gray cuts are for the engine part, while those in green are for the filter part. | ||
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- | {{: | ||
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- | ===== Overview of cuts ===== | ||
- | <WRAP column 45% left> | ||
- | **Filter (F)** | ||
- | ^ u ^ Description | ||
- | | **2** |Sides | ||
- | | **1** |Top | **PF** | ||
- | | **1** |Bottom | ||
- | | **1** |Rear | **AF** | ||
- | | **1** |Stirrer | ||
- | | **2** |Stirrer-motors | ||
- | | **6** |Stirrer-front stands | ||
- | | **2** |Stirrer-rear stands | **SFc** | ||
- | </ | ||
- | **Motor (M)** | ||
- | ^ u ^ Description | ||
- | | **2** |Front/ | ||
- | | **2** |Top/ | ||
- | | **2** |Sides | ||
- | | **4** |Side-a | ||
- | | **4** |Side-b | ||
- | | **2** |Side-c | ||
- | | **2** |Side-d | ||
- | </ | ||
- | ====== Assembly diagrams ====== | ||
- | {{: | ||
- | {{: | ||
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- | ====== Wiring diagram ====== | ||
- | {{ : | ||
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- | The LED strip and the motors are connected in parallel, as shown. A switch can turn off the AC/DC transformer, | ||
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- | The three-position switch allow fan speed selection. It may be replaced by a two-position switch, set to the highest speed. | ||
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- | {{: | ||
- | ====== Budget ====== | ||
- | Most parts are easily found in hardware stores. The electronics come from [[http:// | ||
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- | ^ **Structure** | ||
- | |Fan (Fasco™ A1200 + bracket)| | ||
- | |HEPA Filter (18" | ||
- | |Pre-filters (9 ¾"x19 ¾" | ||
- | |3-positions switch (115V, 15A)| 1 | 6 | **6** | |Glass shelf clips[(: | ||
- | |Power cord (115V, 15A)| 1 | 10 | **10** | ||
- | |AC plug (115V, 15A)[(: | ||
- | |Plywood (quality select, 4' | ||
- | |Primer (1L) & epoxy paint (2L) | 1 | - | **50** | ||
- | |Handles| | ||
- | |Latches| | ||
- | |Screws ¾” et 1 ½”| | ||
- | |Silicon| | ||
- | |Packing tape| 1 | 2 | **2** | |Shaft Coupler (3mm)[(: | ||
- | |Paint brush, roller, tray & sleeve| | ||
- | |Hooks| | ||
- | | | | ^ **942** | ||
- | **Total: 1140** |