Applying a constant pressure to the fluid during a defined time allows to obtain repeatable dispenses in the following conditions:
The PDS expertise
PDS : The concepts time / pressure and volumetric
The dispensing time pressure
The sections of passage of the fluid must be perfectly constant, by the quality and the tolerance of the needle (section of needles ends, various diameters referenced by color, etc.).
The fluid must be stable and its constant viscosity.
The system has to possess a good reminder of drop which guarantees the absence of residue at the end of needle during the last period of cycle.
The system must be perfectly tight, without air inlet.
The dispensing time / pressure must be simple, with varied technology and adapted to the various types of fluid (diaphragm, valves, plungers).
We can note that valves time / pressure are made with very few assembled parts. Their chambers are mono-bodies, support better the pressure, do not leak by aging, speak and clean themselves more easily.
Note : The dispensing time / pressure is not any more enough when the fluid is not perfectly stable, when the temperature or the hygrometry varies, when the viscosity of the fluid is not constant (example two-components) …
If the dispensing time / pressure is a satisfactory solution for well numbers of applications, it does not however bring the necessary precision and the repeatability in certain conditions of applications, what the volumetric dispensing can offer.
The volumetric dispensing
The volumetric dispensing generates a volume of product identical to every cycle. It guarantees a precision of the pourcent order, which corresponds to the tolerances required for the most precise manufacturings. We can differenciate three processes :
Training of a plunger : A plunger covers a distance defined beforehand inside a syringe. PDS proposes the volumetric dispenser without air of PRECIFLUID which is a unique and patented technology.
Training of two plungers (two-component) : These tubes in stainless steel are fed with product and allow a volumetric deposit of every type of products and every type of ratios. It is the principle of the machine two-component PR70 (V) with variable ratios proposed by PDS.
Positive movement : A chamber, which we calibrate the size (so the volume) from a thumb wheel of regulation, empties and filled in every triggering of cycle. Our volumetric valves serial APD works according to this principle which guarantees constant dispenses with a precision lower than the percent, whatever the variations of viscosity.
Training by gearings : An equipment typifies pump with gearing or volume indicator, allows to quantify the uncalled-for product in a constant way in term of volume. it guarantees a precision lower than the percent whatever the variations of viscosity. PDS compose to the groups request, define in functions of the volumes to be moved and of the type of fluid with the best equipments of the market.
Training by worm : An Archimedes’ screw trained by a servomotor allows to move the fluid with constant flow. The fluid pressurized in a syringe fills up the nets of the screw. This technology is considered as volumetric. The rotation of this screw pulls the product towards an exit. The precision of the repeatability is around 2 %.
The processing of products before deposit, preparation of the fluids
The equipment THINKY we propose you allows to improve the homogeneity of the fluids which is often useful. The fluids can insure the mixture of several products. The mixtures obtained are totally homogeneous and without bubbles. The range of mixer THINKY begins with the processing of small capacities 20 ML for the R*D to reach 10 liter / 10 kg quantities for the production.
Our range of pumps, tanks and accessories allow a good management of the fluids upstream.
We can also make for your account the packaging of the fluids you use in syringe, cartridges.
The processing of the deposited products
Polymerization by UV radiation : PDS markets the devices OMNICURE which allow an insolation of glues after dispensing . They are equipped with LED or with lamps with mercury.
Production monitoring : The volumetric dispenser PreciFluid offers the possibility of checking the production in greatest detail. This dispenser radiates a detailed report on the quantities of used products, the numbers of made deposits and may also, after equipment, deliver a visual report.
PDS masters all the removal techniques thanks to its wide range of equipment, certainly one of the most extensive currently available. It ranges from standard equipment that is immediately operational in production to the most complex equipment specifically developed by PDS for specific applications. PDS will respond to your most diverse requests.