Sample Rotator - Amazon Web Services · Sample Rotator This guide shows how to build a standard, single speed rotator for samples and media. Rotators are primarily used to ensure

Sample RotatorThis guide shows how to build a standard, single speed rotator for samples and media. Rotators

are primarily used to ensure the even mixing of solutions requiring constant, gentle stirringmotions.

Written By: Tekla Labs2

Sample Rotator

© 2017 guides.teklalabs.org Page 1 of 15

INTRODUCTION

How They Work: Media rotators continuously and slowly spin a disk that holds sealed vials. Theelectric motor that drives the rotation has been slowed down to a lower rotation speed by eithergeared connections or a potentiometer.

Advantages: Media rotators provide long-term rotation in a very maintenance-free setup. They haveminimal parts and they can be built with a variety of flexible parts.

This Rotator can rotate a total of eight centrifuge tubes at constant speed (our design is for four 50mL and four 15 mL tubes). Various speeds can be set. Power supply is a wall outlet. The motor restson a platform that can be angled to rotate the centrifuge tubes while they are horizontal, vertical, or atapproximately 20 degrees from vertical.

Sample Rotator


TOOLS:Band Saw or Metal Shears (1)

Drill (1)

Screw Driver (1)

Soldering setup (1)

Vise (1)

PARTS:20” x 10” x 1/16” Sheet metal (1)

this is for the rotator body

Heavy Duty Zip Ties (2)this is for securing the motor to the rotatorbridge. Many other methods (bolts, brackets,etc.) are acceptable ways to connect themotor to the bridge.

Toggle Switch (1)this is the on/off switch

Potentiometer knob (1)To adjust the potentiometer resistance (ie setthe speed)

25Ω Potentiometer (1)can be bought with the knob, to adjust thespeed

small DC Motor (1)spins the vial holders

AC to DC Converter (1)Convert power from AC at the wall outlet toDC for the motor to use

Power cord compatible with AC/DCConvertor (1)may come with the converter itself

Epoxy or JB Weld (1)To connect the vial holder disc to aconnection compatible with the DC motor

Metal Screws with washers -Connectsrotator bridge to rotator body (4)

Vial Clips with self tapping screws (8)Holds the centrifuge vials to the vial holderdisc

Sample Rotator


http://www.amazon.com/Olympia-Tool-38-604-4-Inch-Bench/dp/B000VJLY00

Step 1 — Sample Rotator

Figure 1: Build overview

Figure 2: Finished rotator, without any samples loaded.

Step 2 — Rotator Body Module

Using the drawings provided, trace out the design on your piece of sheet metal. The holes markedby arrows indicate the holes used to adjust the rotator angle between horizontal, vertical, or atapproximately 20 degrees from vertical.

Units in the drawing are in inches.

For the prototypes built for Tekla Labs, both steel and 5052 Aluminum were used, the latter beingmuch easier to with.

Sample Rotator



Using either a band saw or metalshears, cut material along thecutting lines.

If desired, use a belt sander or metalfiles to round off any sharp edges orcorners.


Using a 0.5” drill bit, drill out theholes that were marked for theswitch and potentiometer. Dependingon the specific parts you have, thedrill size might vary.

Using a 10-32 clearance drill bit, drillout the mounting holes markedtowards the edge of the sheet.

It’s not necessary to stick to theexact dimensions specified (it’sprobably the case that what youhave access to will be sufficient).

Sample Rotator



Using the bending feature on the metal shears, or a vice, bend the aluminum sheet along the foldlines to the specifications in the drawing

Once again, exact dimensions are not necessary, and “eye-balling” where things need to be shouldbe fine.


With the left over sheet metal, sketch, cut, and bend the bridge for the media rotator and drill outthe respective holes.

Sample Rotator


Step 7 — Vial Holder Module

Make the disc: Using the remaining sheet metal, sketch out a circle according to the specificationslisted in the drawing and with a band saw and belt sander cut out and smooth out the disk (exactprecision is not necessary).


Drilling the holes for the vial holders: Clamping the disk down, you can use a drill and eye balllocations to place mounting holes for the vial holders

It’s important that the holes are equally spaced just so that everything is balanced when spinning.

Sample Rotator



Attach the vial holders with tapping screws.

Epoxy the motor mount to the back of the disk. The connection of the circular plate to the motorwas connected with “JB Weld” to a connector. Epoxy would also work. (Image 3)

Step 10 — Control Wiring Module

Insert the potentiometer and toggleswitch into the holes of the frame.

Sample Rotator



With the potentiometer and switch secured into the frame, you’re ready to begin the wiring process;throughout the wiring process, the diagram will act as a good reference and can help clarify anyquestions you might have.


Solder the positive (+) wire of theAC-DC converter to one of thepoints on the switch and anotherseparate wire to the negativeterminal of the potentiometer.

Sample Rotator



Solder another new wire to the (+)output of the potentiometer.


Connect the open terminal from the switch to the positive (+) terminal of the potentiometer.

Sample Rotator


Step 15 — Final Assembly

Attach the bridge to the frame of the media rotator with screws and washer

Zip-tie the motor to the top of the bridge.


Depending on the type of motor that you have sourced, the method you use to connect theterminals will vary, for this particular setup the motor we found required slip on connectors.Connect the positive output (+) from the potentiometer to the positive terminal of the motor andattach a new wire to the ground (-) of the motor.

Image 1: Close up photo of negative terminal of the motor.

Sample Rotator



The last step is to connect thenegative terminal from the motor,potentiometer and AC-DC convertertogether.

After connecting all the grounds,you’ll have your finished mediarotator. Add the disk to the motor.

Sample Rotator


Step 18 — Validation and Testing

Validations 1. The rotator shouldspin smoothly and at a continuousspeed without wobbling. 2. Adjustingthe resistance in the potentiometershould change the speed of rotation.

Testing 1. Fill two 50 mL tubes withabout 25 mL of water. Both vialsshould contain an equal amount ofwater. Insert the tubes into oppositevial clips on the rotator. 2. Plug inmedia rotator and flip on/off switchto on. Gradually turn knob to highersetting. Rotator disc should spinfaster as potentiometer resistance islowered and motor is operated at ahigher speed. 3. The water in the intubes should become thoroughlymixed throughout the tubes as therotator spins. The rotator should notwobble as it spins.

Sample Rotator


List of specifications

1. Vial holder rotates at an adjustable speed. Maximum rotation rate depends on the motor, powersupply, and potentiometer. An acceptable range is 0-80 RPM.

2. Vial holder can be adjusted to remain horizontal, vertical, or at approximately 20 degrees from vertical.

3. Rotator operates on plug-in wall power. Wall power allows the media rotator to operate for long periodsof time.

This document was last generated on 2017-06-18 05:21:43 AM.

Step 19

Safety and Maintenance

Operator safety 1. When workingwith hazardous chemicals, rotatorshould be kept in secondarycontainer to catch any spills

Operator Safety 2. Always ensuresamples are sealed completely intheir vials.

Maintenance 1. Always balance therotator disc when using it. Thismeans that the vials should beplaced on the rotator disc with radialsymmetry, so that it is evenlybalanced. Each vial should containthe same weight of sample (samevolume if identical samples)

Maintenance 2. Keep electricalcomponents dry.

Maintenance 3. Unplug when not inuse.

Sample Rotator


Documents

Sample Rotator - Amazon Web Services · Sample Rotator This guide shows how to build a standard, single speed rotator for samples and media. Rotators are primarily used to ensure