# US 5,347,851 A · Capillary rheometer plunger pressure transducer and measurement technique

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- Number: US 5,347,851 A
- Document ID: US5347851A
- Status: Granted
- Kind: A
- Application number: 07/977,544
- Filed: 1992-11-17
- Granted: 1994-09-20
- Earliest claimed: 1991-04-04
- Assignees: Dynisco, Inc.
- Inventors: Christopher P. Grudzien, Jr.; Robert Malloy; James F. Reilly
- Web page: https://patentgrep.com/patent/US5347851A

## CPC

- G01N 11/08: by measuring pressure required to produce a known flow
- G01L 9/0077: {for measuring reflected light}
- G01N 11/06: by timing the outflow of a known quantity
- G01N 33/442: {Resins; Plastics}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G)

## Abstract

A capillary rheometer apparatus includes a housing, a plunger, the housing having a reservoir for receiving the plunger in a polymer melt, and a mechanism for blocking flow of the melt out of the reservoir. A driving mechanism is included for driving the plunger longitudinally within the reservoir to move one end of the plunger in contact with the melt. A diaphragm, which is coupled to the one end of the plunger, deflects in response to melt pressure in the reservoir. A mechanism, responsive to diaphragm deflection, determines pressure of the melt. Another mechanism is included for determining the temperature of the melt and a further mechanism is included for indicating longitudinal movement of the plunger. From such determinations, the PVT characteristics and the apparent shear viscosity characteristics of the polymer melt can be obtained.

## Claims

### Claim 1

A capillary rheometer apparatus for characterizing a polymer melt's pressure-volume-temperature relationship, comprising:
a housing;
a plunger;
the housing having a reservoir for receiving the plunger and the polymer melt;
a plug for blocking flow of the melt out of the reservoir;
a driving mechanism for driving the plunger longitudinally within the reservoir;
the plunger having a liquid-filled capillary passage extending therein from one end of the plunger;
a coupler at the one end of the plunger defining within the plunger a chamber in communication with the capillary passage and for sensing melt pressure in the reservoir and transmitting the pressure to the liquid-fill; and
a pressure sensing mechanism, at a second end of and coupled to the capillary passage, responsive to pressure exerted by the liquid fill, for providing an indication of sensed pressure.

### Claim 2 (depends on 1)

A capillary rheometer as claimed in claim 1 further including a temperature controller, coupled to the housing, for controlling the temperature of the housing.

### Claim 3 (depends on 1)

A capillary rheometer as claimed in claim 1 further including a position detecting sensor, coupled to the plunger, for detecting longitudinal movement of the plunger.

### Claim 4 (depends on 1)

A capillary rheometer as claimed in claim 1 further including insulation material surrounding said housing for insulating the housing.

### Claim 5 (depends on 1)

A capillary rheometer as claimed in claim 1, wherein the plug includes a temperature sensor for sensing a temperature of the polymer melt.

### Claim 6 (depends on 5)

A capillary rheometer as claimed in claim 5, wherein the temperature sensor includes a probe inserted into an aperture in the reservoir.

### Claim 7

A capillary rheometer apparatus for characterizing a polymer melt's pressure-volume-temperature relationship, comprising:
a housing;
a plunger having a piston at one end thereof;
the housing having a reservoir for receiving the piston and the polymer melt;
means for blocking flow of the melt out of the reservoir;
a driving mechanism for driving the plunger and piston longitudinally within the reservoir;
means, coupled to the plunger, for determining pressure of the melt;
means, coupled to the reservoir, for determining the temperature of the melt; and
means, coupled to the plunger, for sensing a longitudinal position of the plunger.

### Claim 8 (depends on 7)

A capillary rheometer as claimed in claim 7 wherein the means coupled to the plunger includes an instrumented piston attached to the one end of the plunger.

### Claim 9 (depends on 8)

A capillary rheometer as claimed in claim 8 wherein the instrumented piston includes a seal for sealing space between the piston and reservoir.

### Claim 10 (depends on 7)

A capillary rheometer as claimed in claim 7 further including means, coupled to the housing, for controlling the temperature of the housing.

### Claim 11 (depends on 10)

A capillary rheometer as claimed in claim 10 wherein the means for blocking flow includes a plug disposed within an opening in the housing at one side of the reservoir.

### Claim 12 (depends on 11)

A capillary rheometer as claimed in claim 11 wherein the piston includes a seal thereon for sealing space between the piston and reservoir.

### Claim 13 (depends on 7)

A capillary rheometer as claimed in claim 7 wherein the means for determining pressure of the melt includes an optical pressure sensing mechanism.

### Claim 14 (depends on 7)

A capillary rheometer as claimed in claim 7 wherein the means for determining pressure of the melt includes the piston attached to the plunger and a liquid-filled capillary passage extending within the plunger.

### Claim 15

A capillary rheometer apparatus for characterizing a polymer melt's pressure-volume-temperature relationship, comprising:
a housing;
a plunger;
the housing having a reservoir for receiving the plunger and the polymer melt;
a plug for blocking flow of the melt out of the reservoir;
a driving mechanism for driving the plunger longitudinally within the reservoir to move one end of the plunger in contact with the melt;
a diaphragm, coupled to one end of said plunger, for deflecting in response to melt pressure in the reservoir; and
means, responsive to diaphragm deflection, for determining pressure of the melt.

### Claim 16 (depends on 15)

A capillary rheometer as claimed in claim 15 wherein the means for determining melt pressure includes an optical sensing mechanism.

### Claim 17 (depends on 16)

A capillary rheometer as claimed in claim 16 further including:
means, coupled to the reservoir, for determining the temperature of the melt; and
means, coupled to the plunger, for indicating longitudinal movement of the plunger.

### Claim 18 (depends on 16)

A capillary rheometer as claimed in claim 16 wherein the optical sensing mechanism includes an input optical fiber, an output optical fiber, a fixed reflector, a movable reflector coupled to the diaphragm, a light source, and a light level detector.

### Claim 19 (depends on 15)

A capillary rheometer as claimed in claim 15 wherein the means for determining melt pressure includes the diaphragm at the one end of the plunger and a liquid-filled capillary passage extending within the plunger.

### Claim 20 (depends on 19)

A capillary rheometer as claimed in claim 19 further including:
means, coupled to the reservoir, for determining the temperature of the melt; and
means, coupled to the plunger, for indicating longitudinal movement of the plunger.

### Claim 21

A method for characterizing a polymer melt's pressure-volume-temperature relationship, comprising:
introducing the polymer material into a reservoir contained within a housing;
heating the housing to melt the polymer;
applying pressure to the polymer with a plunging apparatus introduced into an aperture of the reservoir;
measuring a pressure of the polymer melt with a pressure sensing apparatus coupled to the plunger; and
measuring a temperature of the polymer melt with a probe introduced into the reservoir.

### Claim 22 (depends on 21)

The method of characterizing a polymer melt at claimed in claim 21, further comprising the steps of:
repeating the steps of applying pressure, measuring the pressure, and measuring the temperature for a number of pressures applied to the polymer melt.