Most Accurate Dispensing Solutions
Laboratory Powder Dispensers
Our solid dispensers do away with tedious and time-consuming manual dispensing of powders. These laboratory dispensers allow repeated dosing of substances in precise amounts fast, accurately and safe.
Our Products Features
Manual solids dispensing can be laborious as it requires to progressively pour and check the amount on the scale to be dispensed. The solid dispenser (SDH/B/M-1) offers consistent and accurate dosing, time after time.
The auto powder dispenser is able to handle a wide range of solids, beads and microspheres. XQ Instruments offers testing and calibration with the target powders before shipping the device to the customer.
3. Ease of Operation
The user only needs to fill or attach the reservoir to the dispenser, select the number of shots and press the trigger button. Whether battery operated handheld dispenser or bench-top, the powder dispensing equipment is mobile and can be used in different context and location.
Methods & Applications
XQ Instruments dispensers are volumetric powder dispensers. What this means is that they dispense solids or powders by their volume rather than weight. The volume relates to the weight by the bulk density, which is the weight of the sitting solids for a given volume. The bulk density of solids (for example, a certain volume of the fine solids poured into a beaker but do not tapped) differs significantly from the density of the solids as block material.
The volumetric dispenser operates in an open loop where a certain amount of powder is filled into a fixed chamber and then dispensed at the next step of the process. This is repeated with each fixed dose (volume) being accurately dispensed. The dispenser therefore needs to be calibrated for this fixed dose.
The advantage of volumetric dispensing is the speed of dispensing. The disadvantage can be a lack of feedback on the actual weight of the dispensed dose. XQ Instruments has an automated weighing scale accessory to provide feedback and logging of actual measurements for each dose, the amount (weight) dispensed in each cycle. In such a setup, the user can choose to discard dispensed samples that are outside the accepted weight range.
The dispensing disks (the dosing element) are calibrated for a specific dose size as per customer specifications. With the calibrated dispensing disk this dose or selectable multiples of it (up to 99x) can be dispensed. One shot takes 3.5 seconds.
Selecting multiple doses allows to dispense different dose sizes from the same dispensing disk/head, as long as they have a common denominator (resulting in an effect of resolution relative to target doses). However, with multiple doses dispensing time will increase and there can be a stack up error.
To change the single dose values, or switch to a material with different bulk density, the dispensing disk in the dispensing head needs to be swapped with one corresponding to the new value. This takes only a few seconds. Users might have a range of disks available for different materials and dose sizes. Additional disks to new specifications can be ordered from XQ Instruments at any time; e.g., when requirements change.
For switching instantly between materials and dose sizes it can be advantageous to have several heads at disposal in order to swap without the need of clearing out the material and no risk of cross-contamination. The dispensing heads in stand-by can be temporarily stored with material inside (ideally in a dry chamber). Such additional heads with calibrated disks are available as accessories.
Calibration of Dispensing Disks
XQ Instruments volumetric solid dispensers employ as dosing element rotating dispensing disks with calibrated chambers. These disks are custom machined precisely to customer dosing specifications and are quickly exchangeable in the dispensing heads.
Powder doses can be specified for calibration in volume or (more typical) in mass. The dispensing principle of XQ Instruments products is volumetric. Therefore, if the dose size is specified in mass, it needs to be converted to volume. The relation of volume to mass is defined by the bulk density of a granular material. Bulk density can vary significantly between materials; common substances fall in a range of 0.2g/ml to 2.0g/ml. That means the difference in mass of the same volumetric dose can vary by a factor of 10.
The relation of dose weight to dose volume can be established with this calculator:
The bulk density of a specific powder can be obtained from material data sheets or literature; here is a list of common materials with their values.
For the dose calibration of our solid dispensers, there are 3 ways to specify the single dose calibration of a dispensing disk or dispensing head:
The target dose volume, typically in mm³
The target dose weight and a material sample (preferred for precision)
If an actual sample of the material is available for calibration, the dispensing volume can be tweaked until the mean of a string of doses is very close on the target. This approach results in the best precision in dispensing
The target dose weight and nominal bulk density of the material
Results in volume
If nominal bulk density is not available, the value can be established by weighting of a specific volume of the material (say 50ml, e.g. in a syringe barrel or beaker). That value together with the mass dose target will allow to calibrate.
Bulk density can be obtained from a weighted sample with the calculator below:
The dispensing disks can be calibrated to any volume in the range of the individual head size. These volume ranges are as follows:
|Dispensing head size||Volume calibration range||Dispenser|
|Small head||2.3 mm³ – 300mm³||SDH-1, SDB-1|
|Mid-size head||2.3 mm³ – 715mm³||SDH-1, SDB-1|
|Large Head||5 mm³ – 8,100mm³||SDH-1, SDB-1|
|XL Head||10 mm³ – 78,000mm³||SDB-2|
For small doses, the smaller dispensing heads are not more precise than the large ones. On the contrary, the large dispensing head can cope best with challenging materials in small doses. Therefore, it is the typical choice for the larger benchtop SDB-1. For the more compact form factor of the handheld SDH-1 the small and medium size head would be usually selected, even though the large head will also fit. The SDB-2 comes with its own XL head.
Microspheres or glass beads are dispensed into a variety of mediums for specific applications. These glass beads exhibit high mechanical strength, chemical stability and limited thermal expansion. They flow freely which is a good quality for accurate, repeated dispensing by XQ Instruments dispensers. As glass beads are resistant to moisture, they remain consistent in their density and do not stick together forming clumps. They are one of the most commonly used solids in our dispensers and sizes vary from the nanometres to millimetres range.
1. What is volumetric dispensing?
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.
2. How precise are the dispensers?
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%.
3. Which materials can be dispensed?
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.
4. How small can the doses be?
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.
5. Are the dispensers able to dispense beads?
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.
6. Can I just dial in a dose value and have it dispensed?
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.
7. What influence does ambient humidity and moisture in the material have?
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.
8. Should I order additional dispensing heads or dispensing disks for different materials and dose sizes?
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.
9. What is the fill volume of the dispenser reservoirs?
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.
10. What container sizes can be filled with the dispensers?
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).
11. I have very small containers; how do I fill them without spilling?
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.
12. Is the material sealed inside the dispensing heads?
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.
13. How can the parts in contact with the material to be dispensed be sterilized?
The whole powder path can be easily dismantled and sterilized by wiping, submersing or autoclaving.
14. What are the materials used in the dispenser which come into contact with the powder?
The component parts in contact with the powder are made of polycarbonate, with some small stainless-steel parts. If required, these metal parts can be replaced with polymer parts.
15. Can the dispensers be used continuously in a production environment?
Our SDB-1 and SDB-2 dispensers can withstand continuous operation in a production environment, being manually operated or as part of an automated system.
16. Can the dispenser be mounted into a larger automated system?
This is a fairly typical application for the SDB-1 and SDB-2. We can assist in integration and customization.
17. Can the dispensers be triggered by an external controller, like a PLC?
On the SDB-1 there is a connector for external switches, which can also be used to trigger dispensing from a PLC. There is also a USB port from which all functionalities are accessible via a proprietary PC software.
18. What is the IQ PQ like?
The IQ PQ consists mainly of a repeat of our outgoing test and verification onsite. We can provide templates for it.
19. Will the accuracy degrade over time?
If abrasive material is used, the dispensing disks can wear resulting in degradation of dose size calibration and dose variation. In this case a replacement disk should be ordered, which will bring the performance back to the original level.
20. How to do periodic re-calibration of the dispenser?
It is sufficient to repeat the dose test as our outgoing inspection and specified in our IQ-PQ template. If dose values have drifted, a duplicate disk to the original specifications can be ordered from us.
21. What is the maintenance required?
Besides cleaning and checking through the equipment as well as periodic verification of the dose values there is no regular maintenance required.
22. Are there components that need periodic replacement?
Generally, there are no parts that need periodic replacement within a reasonable lifecycle. However, the dispensing disks should be verified regularly and might need replacement depending on properties of the material used.
23. How about repairs and spare parts?
We have a wide range of spare parts available. Repairs are supported on customers’ site with parts and instructions, or will be performed when equipment is sent back to us.
24. What is the warranty like?
There is a warranty of one year covering all components against manufacturing defects.