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Fluidics PDF Print E-mail

If using one of MicroFab’s integrated printheads, the specific implementation takes care of the reservoir and connection of the reservoir to the microdispensing device. This section only applies if the microdispenser was purchased separately and the user is setting it up on his own.


Tubing and connecting to the device

The MINSTAC fitted MicroJet devices have a male threaded end fitting that can be attached to tubing and fittings available from The Lee Company (www.theleeco.com).

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A 062 MINSTAC Tubing Union (Part # TMUA3201950Z) can be used to interface the MINSTAC fitting on the MicroJet device with a MINSTAC Male Coupling Screw attached to Teflon tubing, as shown in the top image. Stocked pre-assembled tube sets having MINSTAC Male Coupling Screw on both ends of Teflon tubing (0.062” OD) are available (TUTC3216910L - 10 cm, TUTC3216915L - 15 cm, TUTC3216930L - 30 cm, TUTC3216960L - 60 cm).

The 062 MINSTAC Fitting End Kit (Part # TMZA3202010Z) can be used to attach the male fittings to Teflon tubing in order to obtain custom lengths. Additional Teflon tubing can be ordered from Lee (TUTA3216930D - 10 feet).

Another option is to interface the MINSTAC fitting on the MicroJet device using the 125/156 MINSTAC Female Tube - Luer Adapter (TMRA9502950Z) with the 125/156 MINSTAC to 062 MINSTAC Adapter (TMDA3203950Z) to connect to male Luer fittings, as shown in the bottom of the figure.

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The barb fitting of MJ-AB MicroJet devices can be attached directly to C-Flex tubing, as shown in the top device in the figure. Another option is to slip the PTFE microbore tubing, 0.022 x 0.042 in (0.55x1 mm) E-06417-21 (Cole Parmer) into a small section (6.0mm) of C-Flex tubing, 0.031 x 0.094 in (0.7x2.3 mm) E-06422-01 (Cole Parmer) that has been slipped over the barb fitting on the device, as shown in bottom device in the figure.

The C-Flex tubing or PTFE microbore tubing can then be connected to the syringe barrel adapter described below by inserting the metal needle end of a female luer fitted blunt needle into the C-Flex tubing (18 gauge needle part # 7018122) or PTFE microbore tubing (22 gauge needle part # 7018272) from Nordson EFD (www.nordson.com).

The approach illustrated at the bottom of the figure allows the use of higher resistance materials. For that configuration, use TYGON® Ultra Chemical Resistant Tubing EW-95630-00 (Cole Parmer) and then the same PTFE tubing described above.


Reservoir

alt The simplest reservoir is a syringe. A syringe barrel adapter assembly available from Nordson EFD (www.nordson.com) (cat. # 7012341, 7012054, 7012339, 7012338) can be attached to a syringe barrel reservoir (cat. # 7012072, 7012094, 7012112, 7012134) to provide for a reservoir to the MicroJet device (see figure to the right). The syringe barrel reservoirs and adapter assembles are available in 3cc, 5cc, 10cc, 30cc and 55cc volumes. The syringe barrel reservoirs and adapter assembles are available in 3cc, 5cc, 10cc, 30cc and 55cc volumes. The connection at the bottom is a Luer type fitting. Blunt needles from Nordson EFD (www.nordson.com) can be used to connect to flexible tubing.

When using the AT microdispensing devices, the same type of fitting shown at the bottom of the figure with the AT devices is used. The Luer end is connected to the syringe and the Minstac end connects to the Teflon tubing with two male Minstac ends.

The syringe barrel reservoir and adapter assemblies provide the means to connect to the space above the fluid. This connection can be used for purging and maintaining the fluid flush with the orifice.

For small volumes a 6.5cm section of PTFE microbore tubing, 0.022 x 0.042 in (0.55x1 mm) E-06417-21 can be inserted into a small section (6.0mm) of C-Flex tubing, 0.031 x 0.094 in (0.7x2.3 mm) E-06422-01 that has been slipped over the barb fitting on a barb fitted MicroJet device (top of the figure). Another 6.0mm section of C-Flex tubing, 0.031 x 0.094 in (0.7x2.3 mm) E-06422-01 is slipped onto the distal end of the PTFE microbore tubing. The PTFE section of tubing will provide a reservoir including the dead volume within the MicroJet device. The length of the tubing determines the volume of the reservoir. A micropipette is used to load the tubing reservoir attached to the MicroJet device by inserting the pipette tip into the C-Flex tubing. Carefully remove the pipette tip while keeping the plunger in the pressed position after loading the tubing reservoir with fluid. Be sure to filter all fluids prior to use to prevent clogging the orifice.


Filter

In some instances, a filter will eliminate particles that could clog the microdispensing device orifice. When using a syringe reservoir the easiest implementation is a 25mm syringe filter. Typically, a 5?m pore size is sufficient. The filter material needs to be compatible with the dispensed solution. Water-based fluids can be filtered using 5.0 micron pore size nylon syringe filters (Scientific Company F2500-50). Solvent-based fluids can be filtered using 5.0 micron pore size PTFE syringe filters (Millipore Millex-LS SLLS 025 NS). New syringe filters should be flushed prior to use to remove particles from manufacturing. Small volumes (50-500 microliters) can be filtered (0.22 microns) using microcentrifuge filters (Millipore Ultrafree-MC UFC30GV00).