- Diffusion Cells / Franz Diffusion Cells / Franz Cells - | ||||
Equipment that measures permeation through membranes |
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Franz Cells | Side - Bi - Side Cells | In Line Cells | Flow Type Franz Cells | Cell Stands |
Nail Adapter for Franz Cells | Franz Cell Accessories | Answers to Frequently Asked Questions | ||
Automated Systems | ||||
In Line Diffusion Cell | SES Thermostat SC100 | Franz Cell System | ||
Stirrers |
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V-Series | H-Series |
Answers to Frequently Asked Questions | |||||
1 -
Franz Cells are individually hand blown diffusion cells made of two
borosilicate glass components. The upper part may be called the cell cap,
cell top, donor chamber, or donor compartment. The lower portion is
generally called the body of the cell, sometimes it is referred to as
the receptor chamber but in the case of jacketed cells this is
misleading as the receptor chamber is the innermost portion of the cell.
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2 - The
upper surface of the cell body and the mating lower surface of the donor
chamber are together known as the joint. The membrane through which the
permeation or transport is being studied is placed in the middle of the
joint and held in place with a clamp. Please see the tables at the
bottom of this page for basic dimensions for all our cells. The orifice of a Franz Cell is the area to which the donor and receptor
chambers are exposed. In the case of blown glass diffusion cells this
area is circular. When referring to a Franz Cell, the size of the cell
is the orifice diameter of the joint at the mating surface and is not
the outer diameter of the joint. Please see the pictures and table at
the bottom of this page for orifice, approximate outer joint diameters,
and other specifications. There are presently four varieties of joints available for Franz Cells: flat ground, flat flange, o-ring, and spherical or corneal. Please refer to the pictures below. The most popular joint is the flat ground variety which is sometimes called a flat ground o-ring joint. This joint is stronger than the flat flange joint of the same orifice diameter and is useful for almost any membrane thinner than 4mm. Flat flange joints have clamps which allow membranes or devices up to about 10mm in thickness and even 30mm with longer screws. O-ring joints are generally used for thin synthetic membranes which the user wishes to hold over the top of the receptor chamber using the o-ring to compress the membrane. Some users also hold skin in place with o-ring joints. We also have Nail Adapters that allow fingernail or toenail specimens to be placed in both Franz Cells and Side-Bi-Side Cells.
Spherical joints are used for corneal work and presently there are two sizes available with ball diameters of 12mm and 18mm. The specifications for them are shown at the very bottom of this page. |
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3 - As
previously stated, the orifice diameter is referred to when describing
the size of a Franz Cell. If the receptor chambers were always
cylindrical, excepting the sampling arm, receptor chamber volumes would
always be the same for a given orifice diameter. But studies often
require different volumes and we make Franz Cells with different
receptor chamber volumes while maintaining the standard Franz Cell
height. The two drawings below are approximations of 5mm jacketed Franz Cells. The cell to the left is our standard cell which has a 5ml volume. Notice that the receptor chamber diameter is larger inside the heating jacket. This is to provide the 5ml volume that many researchers prefer. The cell on the right is also a 5mm cell and the receptor chamber diameter continues almost all the way to the bottom of the cell where a bulb shaped volume exists for the purpose of making room for a stirbar. The receptor chamber volume of this jacketed cell is about 3ml and is the smallest we can make in a jacketed cell.
Once again, the two drawings below illustrate different ways to change the receptor chamber volume of a jacketed Franz Cell. The lefthand drawing approximates a 15mm cell with a cylindrical receptor chamber of 12ml. The righthand drawing shows a 20mm cell having a receptor chamber of reduced diameter and height, in this case the same size as a 15mm cell, inside the heating jacket. Our standard 20mm cells have 15ml receptor volumes, but the one shown is approximately 12ml like the 15mm cell.
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4 -
Jacketed cells may be connected to a water source for temperature
control. Unjacketed cells may be placed in a dry block heater, water
bath, or temperature controlled environment if needed. The receptor
chambers and the jackets are hand blown together at the same time and
cannot be separated. Heating jackets cannot be added to previously
manufactured unjacketed cells.
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5 - The
sampling arm, heating jacket inlet and outlet tubes, and optional flow
porting of standard Franz Cells are all made from 6mm O.D. tubing that
has a 1.0mm wall thickness. Given the tolerances of the tubing as
dictated by the manufacturer of the tubing itself, the inner diameter of
the tubing is about 4mm. Syringes with 2mm O.D. needles can easily be
used to sample Franz Cells. Other diameters are supplied at the user's
request. Bear in mind that the sampling arm volume of standard Franz
Cells is unstirred volume and should be kept as small as possible. |
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6 - The
discussion regarding the location of the calibration mark on the
sampling arm of a Franz Cell is controversial, always lively, and
probably worth a web page by itself. PermeGear's position is this: When
filling a standard PermeGear Franz Cell receptor chamber to the line on
the sampling arm, the volume required is the number of milliliters
etched onto the sampling arm next to the calibration mark. We try to
hold the volumes of the smaller varieties to +/-.2ml from the standard
and the larger sizes to +/-.5ml.
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7 - PermeGear V-Series Stirrers are for jacketed Franz Cells and are available in 3, 6 and 9 cell models. Aside from the number of cells that the stirrers may hold, the user must take into consideration the center to center distance of the cells when ordering a stirrer. The V3 stirrer that holds 3 cells and the V9 stirrer that holds 9 cells locate the cells 5 inches or 127 millimeters from the center of one cell to the center of the next. The V9-C Stirrer also holds 9 cells but the center to center distance is 2.6 inches or 66 millimeters. In the case of the larger 25mm Franz Cells whose flat flange clamps are 65mm wide, handling the cells may be cumbersome. In the case of the 30mm Franz Cells whose flat flange clamps are 71mm wide, placing the cells in the cell holders is not possible.
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Dimensions of Standard Franz Cells |
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Standard 5mm Jacketed or Unjacketed Franz Cell Specifications | |||||
Flat Ground Joint | Flat Flange Joint | O-ring Joint | |||
Joint I.D. | 5mm | N/A | 5mm | ||
Joint O.D. | 19mm | N/A | 19mm | ||
Receptor Volume | 5ml | N/A | 5ml | ||
Orifice Area | .20cm² | N/A | .20cm² | ||
Jacket Diameter | 30mm | N/A | 30mm | ||
Standard 7mm Jacketed or Unjacketed Franz Cell Specifications | |||||
Flat Ground Joint | Flat Flange Joint | O-ring Joint | |||
Joint I.D. | 7mm | N/A | 7mm | ||
Joint O.D. | 22mm | N/A | 22mm | ||
Receptor Volume | 5ml | N/A | 5ml | ||
Orifice Area | .38cm² | N/A | .38cm² | ||
Jacket Diameter | 30mm | N/A | 30mm | ||
Standard 9mm Jacketed or Unjacketed Franz Cell Specifications | |||||
Flat Ground Joint | Flat Flange Joint | O-ring Joint | |||
Joint I.D. | 9mm | 9mm | 9mm | ||
Joint O.D. | 25mm | 27mm | 25mm | ||
Receptor Volume | 5ml | 5ml | 5ml | ||
Orifice Area | .64cm² | .64cm² | .64cm² | ||
Jacket Diameter | 30mm | 30mm | 30mm | ||
Standard 11.28mm Jacketed or Unjacketed Franz Cell Specifications | |||||
Flat Ground Joint | Flat Flange Joint | O-ring Joint | |||
Joint I.D. | 11.28mm | 11.28mm | 11.28mm | ||
Joint O.D. | 28mm | 30mm | 28mm | ||
Receptor Volume | 8ml | 8ml | 8ml | ||
Orifice Area | 1.00cm² | 1.00cm² | 1.00cm² | ||
Jacket Diameter | 30mm | 30mm | 30mm | ||
Standard 15mm Jacketed or Unjacketed Franz Cell Specifications | |||||
Flat Ground Joint | Flat Flange Joint | O-ring Joint | |||
Joint I.D. | 15mm | 15mm | 15mm | ||
Joint O.D. | 30mm | 30mm | 30mm | ||
Receptor Volume | 7.5 or 12ml | 7.5 or 12ml | 7.5 or 12ml | ||
Orifice Area | 1.77cm² | 1.77cm² | 1.77cm² | ||
Jacket Diameter | 30mm | 30mm | 30mm | ||
Standard 20mm Jacketed or Unjacketed Franz Cell Specifications | |||||
Flat Ground Joint | Flat Flange Joint | O-ring Joint | |||
Joint I.D. | 20mm | 20mm | 20mm | ||
Joint O.D. | 37mm | 43mm | 37mm | ||
Receptor Volume | 15ml | 15ml | 15ml | ||
Orifice Area | 1.77cm² | 1.77cm² | 1.77cm² | ||
Jacket Diameter | 30mm | 30mm | 30mm | ||
Standard 25mm Jacketed or Unjacketed Franz Cell Specifications | |||||
Flat Ground Joint | Flat Flange Joint | O-ring Joint | |||
Joint I.D. | 25mm | 25mm | 25mm | ||
Joint O.D. | 44mm | 50mm | 44mm | ||
Receptor Volume | 20ml | 20ml | 20ml | ||
Orifice Area | 4.91cm² | 4.91cm² | 4.91cm² | ||
Jacket Diameter | 30mm | 30mm | 30mm | ||
Standard Spherical Joint Jacketed or Unjacketed Franz Cell Specifications | |||||
Orifice in Sphere | 5mm | 9mm | |||
Sphere Diameter | 12mm | 18mm | |||
Receptor Volume | 5ml | 5ml | |||
Orifice Area | .20cm² | .64cm² | |||
Jacket Diameter | 30mm | 30mm | |||
SES GmbH - Analytical Systems | |||||
Friedhofstr. 7-9 - 55234 Bechenheim / Germany | |||||
phone.: +49 6736 1301 | fax: +49 6736 1305 | Email: ses_analysesysteme@t-online.de |