Steroglass

SPEEDEX - The universal liquid-dispensing pump

This high performance laboratory pump is unique in its kind‚because itcan dispense liquids with a resolution of 50 ul with a range of volumesprogrammable from 100 ul to 5000 ml. (the range can be extended tohigher volumes).


ADVANTAGES



High precision:
the dual reciprocating piston dispensing system allows a resolution of 50 ul


Wide flow range:
from 1 ml/min to 1.5 l/min with a single pump model


Excellent Riproducibility:
the constant flow is maintained over time‚ contrary to other dispensingsystem such as peristaltic and diaphragm pumps subject to aging andrequiring continuous re-calibrations.


Chemically inert:
all parts in contact with the pumped fluid are made fromchemically-inert materials‚ such as PTFE‚ glass and PEEK.Theinstruments is therefore suitable for critical applications such asthose involving: aggressive liquids‚ organic solvents‚ biologicalsolutions‚ etc.


Flexible and versatile:
meets all pumping‚ dispensing and trasferring needs within an unrivalled wide range of flowing rates and volume capacity.


Progrmmable and multifunctional:
a fully-programmable electronic controller offers a wide choice ofoperating modes: continuous pumping or transferring at constant flowrate‚ manually-controlled or automatic dispensing of programmedvolumes‚ multi-step and multi-cycle dispensing with individuallyprogrammable flow rate‚ delay time and volume for each step.


Pulsation-free:
the unique design of the pumping system allows a continuous flow ratefree from pulsation and interruptions. A very high accuracy andreproducibility can be obtained both in terms of flow rate anddelivered volume: excellent for low-pressure chromatography and flashchromatography.


Pedal Control:
A pedal control is available as a useful accessory for applicationsrequiring hand-free operations or for remote operations such as:dispensing of hazardous fluids under a fume-hood‚ or bottling in smallvolume productions.


Self-priming:
the system is entirely self-priming‚ thanks to the special piston construction and the absence of dead volume zones.


Maintenance-free
the careful choice of materials and the advanced constructiontechniques make this pump a virtually maintenance-free device.Thehydraulic circuits only need to be cleaned every time the fluid type ischanged: the continuous flow function simplifies and speeds up theoperation.


Easy to use:
requires no special skills and can be used by any operator.

The pumping system is composed of two calibrated glass syringes‚ 100cc each‚ with the pistons operating in reciprocating mode.

The piston are made of solid‚ virgin PTFE‚ the sealing is guaranteed bya particular system with the O-R seals separated from the solvent by aspecial under-skini system.

The hoses are in semiflexible PTFE and the couplings are screw-type with nipples in PEEK.

Two PTFE valves of diaphragm-type provide automatic flow reversal when the two syringes reach the travel limit.

The piston shafts of the two syringes are guided by two high-precisionlinear bearings and are driven in a perfectly complementary manner by abacklash-free timing belt and pulley system.

The high-torque stepper motor (4Nm) guarantees a resolution of 400steps per revolution of the motor shaft.The advancement of the pistonsis approximately 0.05 mm per motor commande pulse.Since the delivery ofthe
syringes is perfectly linear and corresponds to 100 ml for a pistonstroke of 100 mm‚ a final resolution of 50ul is obtained for eachcommand pulse sent to the motor.

The system microcontroller supplies the stepper motor with discretesteps or continuous rate at the required speed as needed by thespecific duty. The particular mechanical system design is such thateach movement produces exactly the delivery of equal amounts ofsolvent‚ at a constant flow rate and is linearly proportional to themovement speed.

The limit switch system automatically reverses the direction of themotor shaft rotation when the syringe pistons reach the upper or lowertravel limit. This system is completely trasparent to the controlsystem‚ which continues to send pulses for the delivery of the liquid.When one syringe is completely ‚ its mate‚ always moving in theapposite direction‚ (which always moves in a direction opposite to thatof its mate) will have just been filled up. At this point the automaticsystem will reverse the rotation of the motor and change thecombination of the 2 valves status. The next command pulse will makethe just filled syringe begin the delivery cycle‚ while the
syringe will start the aspiration cycle.

The valve system (normally closed in stand-by or when switched-off) andthe perfect syringes sealing‚ implicitly guarantee the complete absenceof siphoning effects during quiescent periods‚ prevent the contact ofthe stationary solvent with air‚ pollutants‚ stop evaporation or‚worse‚ crystallization in case of saline solutions.

The self-priming system: the particular conical shape of the piston topand the syringe caps‚ the use of water-repellant material such as PTFE‚and the absence of dead volumes‚ bleed every trace of air after just afew starting cycles carried out by the system. This also occurs‚abviously‚ for the washing of the pumping components and for thecomplete ing of the system during maintenance or prolonged restperiods. The changing of the solvent and the subsequent rinsingi withthe new solvent is also greatly facilitated by this feature.

The outgoing flow is perfectly constant and virtually free ofinterruptions‚ even when the exchangingi of functions between the twosyringes takes place: to maintain the maximum precision regarding theabsolute value of the liquid dispensed‚ a signal is nonethelessgenerated corresponding to the short deadi time occuring during themotor direction reversal and the exchange of the four solenoid valves(time during which the solvent is not delivered). The microcontrollertakes this time into account and consequently adjusts the real value ofthe volume delivered both in every instant and overall.

The dual reciprocating pistons design guarantees a solution flow thatis continuous and constant for any quantity: while one syringe is atthe injection stage‚ the other is being filled‚ and the functions areinterchanged autotomatically at the end of the stroke withoutinterrupting the filling operation. The maximum quantity of solutionthat can be transferred is thus limited only by capacity of the storagereservoir from which the solvent is drawn directly.