Laboratory Powder Dispensers

Volumetric dispensing is the dispensing principle which portions the volume of a sample (like a measuring spoon). If the mass is used instead (on a scale) the principle is gravimetric dispensing.

Precision depends on dose size (larger doses are more consistent) and material properties. The dispensers can also be tweaked to improve performance for specific materials; we can assist in that. Typical values (for typical materials and dose sizes) are +/- 3%.

Most solids can be dispensed. A list of materials typically used on our dispensers can be found here. Dispensing error will vary with specific material properties. Challenges are moist or wet materials, substances which tend to clump strongly and granular materials with very irregular granule size and shape.

A typical lower limit is 2mg of material. However, at very small dose sizes the dosing error increases, and some challenging materials might not dispense consistently anymore.

Yes, our dispensers can dispense beads up to a diameter of 3mm if the dispensing disks are adjusted to the specific size. Beads need to be very consistent in diameter.

Unfortunately, single dose sizes are determined by the dispensing disks which can only be modified by exchanging the disks. Only multiples of the calibrated dose size of the dispensing disk can be selected.

Dose mass will fluctuate with moisture content, while the amount of material, dosed by volume, stays the same. In gravimetric dispensing this can lead to a masked error, since the dose mass seems consistent. However, the material dispensed consists of a variable part of water, with accordingly more or less material. In volumetric dispensing this difference in mass can be seen when weighting. The dose of the actual material volume is consistent.

Very dry environments (e.g dry labs) can amplify issues with powders prone to static.

If there is a frequent swap between materials, additional dispensing heads are useful since the material can be left inside and it is not necessary to empty out the material and clean; also there is no risk of cross-contamination. Each head can be calibrated to different specificatons (material density and dose size).

Dispensing heads with material can be set aside at least temporarily on a rack to be swapped in again when needed.

If, however, materials and doses sizes are only changed between batches, just having the additional dispensing disks corresponding to the various materials and dose sizes will be sufficient and more economical.

Small dispensing heads come with vials of 40ml or 60ml. The tube type reservoir on the medium size head has a volume of 150ml. For large dispensing head reservoirs of 200ml, 400ml and 1l are available. Sizes can also be customized.

The inner diameter of the tip of the dispensers goes from 3mm (SDM-1 and small head), 4mm (medium size head), 7mm (large head) to 9mm (SDB-2). However often the funnel tip size will need to be increased to prevent clogging of specific materials. The tips can be customized for small containers and special applications (e.g. longer, tube-like funnel).

We can customize tips for very small containers; tubes or vials. However, the material properties of the dispensed substance must be such that it is able to flow through an orifice small enough for the necks of such small containers.

The dispensing heads are fully enclosed, but not hermetically sealed. Most materials can be temporarily left stored inside. For more extended periods, storing the head with material in a dry cabinet can prevent moisture absorption.