Glass Capillary Array
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Glass Capillary Arrays Collimation Gas flows X-rays Calibrated leaks Controlled air flow Differential pressure barrier In-line filtration Optical beam splitters Laser entrance windows Precise pore sizes High heat tolerance (to 450 °C) Mechanical strength Optical quality finishes Custom shapes and materials Applications support Glass Capillary Arrays (GCAs) consist of millions of precision glass capillary tubes fused together to produce a uniform and mechanically rigid structure. They can be supplied as circular or rectangular thin plates and offer sieve-like filtration with a positive particle size cut-off. GCAs are strong, self-supporting devices with exceptional thermal and chemical stability; they can be manufactured to withstand temperatures greater than 450 °C for applications in severe environments. Pore Size Bias Angles Standard pore sizes for GCAs range from 2 to 50 microns. Other pore sizes can be special ordered. Stringent process controls ensure that pore size variations are less than 1% within a single GCA. There is a 6% maximum pore size variation between GCAs. The capillaries within an array may be offset from perpendicular to the input surface. Angular displacements from 0° to 19° may be ordered. Pore Density Typically, GCAs are manufactured to have an open area ratio of 45% or greater, depending on pore diameter. This provides the ideal combination of a high flow rate and high mechanical strength. As a special order, as few as one pore in a 25 mm disc can be used as a calibrated leak. Flow Rate The flow rate for a 25 micron pore, 0.5 mm thick GCA is approximately 2.5 ml/sec/cm2 with a differential pressure of 1 cm of mercury, and 16 ml/sec/cm2 with a differential of 6 cm of mercury, measured using distilled water at 23° C. Actual flow rates for any capillary array depend on fluid characteristics, aspect ratio, and flow characteristics of the holding apparatus. Mounting Regardless of the thickness, the aspect ratio (pore length to diameter) should be ≤100.The standard GCA thickness is 0.5 mm. GCAs can be manufactured to order with a thickness from 0.25 mm to 6 mm. Solid border GCAs are compatible with most existing Millipore or Nuclepore equipment, requiring little or no hardware modification. For high temperature or high pressure applications, GCAs may be fritted in a metal flange and mounted on metal or glass tubing. In many other applications epoxies can be used for mounting. Standard Materials Special Requirements Lead glass is used as the basic standard matrix due to its mechanical strength and chemical stability. The density is 4.44 g/cc and the nominal refractive index is 1.70. It has a thermal expansion coefficient of 77 x 107 Whenever possible, standard dimensions should be used. The following options can be supplied on a special order basis. When requesting a quotation specify all characteristics listed below plus any special requirements. For special shape or pore size please specify the following: • Diameter or Length and Width • Thickness • Pore Size • Bias Angle (0-19°) Unless otherwise specified, surface finish will be matte, open area ratio will be nominally 45% and material will be lead glass. per °C. Surface Finish GCAs can be supplied with a ground matte finish (9 micron abrasive) on both faces; a polished surface on both faces is also available. In either case, the pore surfaces have a smooth finish. The input surface can be blackened to minimize light scattering.

Glass Capillary Arrays can be ordered in a wide variety of shapes, sizes, thicknesses, and pore sizes. Custom applications are welcome. Microscopic view of a Glass Capillary Array with precision 5 micron pores. Capillary Area Dia/Dim (mm) round round round round round round round round round round round round rectangular square rectangular square Aspect Ratio RIM (solid glass border) Outside dimensions (mm) Diameter or L x W Finish M Ground P Polish Material L LongLife™ MCP10 glass S Soda lime glass – rimless, standard pore sizes: 7µm pitch/5µm pore 14µm pitch/10µm pore 70µm pitch/50µm pore...