Bladder for liquid dispenser
First Claim
1. In a dispenser for dispensing a liquid under pressure comprising an expansible elastic bladder for holding the liquid under pressure, the elastic force in whose walls provides the force by which the liquid is dispensed, a flow passage from the bladder, and flow metering means in the flow passage, the improvement wherein the bladder is made of vulcanized, synthetic polyisoprene having a stress relaxation of less than about 10% and a low frequency hysteresis of less than about 10%.
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Abstract
An improvement in liquid dispensers, especially those used to infuse liquid drugs into patients, that dispense liquid under pressure from an expansible, elastomer bladder is disclosed. The improvement is that the bladder is made from synthetic vulcanized polyisoprene, especially polyisoprene that has 90% to 98% cis linkages and has been vulcanized with an organic peroxide, such as dicumyl peroxide, at a concentration of 5.5×10-3 to 7.5×10-3 moles of peroxide per 100 grams of polyisoprene.
65 Citations
17 Claims
- 1. In a dispenser for dispensing a liquid under pressure comprising an expansible elastic bladder for holding the liquid under pressure, the elastic force in whose walls provides the force by which the liquid is dispensed, a flow passage from the bladder, and flow metering means in the flow passage, the improvement wherein the bladder is made of vulcanized, synthetic polyisoprene having a stress relaxation of less than about 10% and a low frequency hysteresis of less than about 10%.
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9. In an apparatus for infusing liquid drug into a patient at a controlled rate and under an essentially constant pressure comprising:
- an elastomeric, expansible, generally cylindrical bladder for holding the liquid, said bladder having a deflated length that is not less than 5 times the deflated outside diameter and a wall thickness of from 0.01 to 1 times the deflated inside diameter, the elastic force in the wall of the bladder providing said pressure;
a flow passage that communicates with the interior of the bladder and extends to the infusion site; and
a flow control element in the passage for regulating the flow of liquid through the passage, the improvement wherein the bladder is made from synthetic, vulcanized polyisoprene having a stress relaxation of less than about 10% and a low frequency hysteresis of less than about 10%. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
- an elastomeric, expansible, generally cylindrical bladder for holding the liquid, said bladder having a deflated length that is not less than 5 times the deflated outside diameter and a wall thickness of from 0.01 to 1 times the deflated inside diameter, the elastic force in the wall of the bladder providing said pressure;
Specification