# US 2017/0284950 A1 · Machine for testing thermal resistance of plastic materials, in particular thermoplastic polymers

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- Number: US 2017/0284950 A1
- Document ID: US20170284950A1
- Status: Published application
- Kind: A1
- Application number: 15/478,603
- Filed: 2017-04-04
- Published: 2017-10-05
- Earliest claimed: 2016-04-05
- Assignees: Illinois Tool Works Inc.
- Applicants: Illinois Tool Works Inc.
- Inventors: Giuseppe Galizia
- Web page: https://patentgrep.com/patent/US20170284950A1

## CPC

- G01N 25/18: by investigating thermal conductivity (by calorimetry G01N25/20; by measuring change of resistance of an electrically-heated body G01N27/18)
- G01N 3/42: by performing impressions under a steady load by indentors, e.g. sphere, pyramid (G01N3/54 takes precedence)
- G01N 33/2805: {investigating the resistance to heat or oxidation}
- G01N 25/04: of melting point; of freezing point; of softening point
- G01N 33/442: {Resins; Plastics}
- G01N 2203/02: Details not specific for a particular testing method
- G01N 2203/0202: Control of the test
- G01N 2203/0226: High temperature; Heating means
- 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)

## Abstract

Machine for testing thermal resistance of plastic materials, comprising a tank configured, in use, to be filled for example with a heat-transfer fluid; a heating coil for heating the heat-transfer fluid; a temperature sensor generating a temperature signal of the heat-transfer fluid; and a control unit calculating a degradation index of the heat-transfer fluid on the basis of the temperature signal. In particular, the degradation index is calculated by determining the temperature range associated with the temperature signal, updating the corresponding partial heating time, and calculating the weighted sum of the partial heating times previously saved in memory and pertaining to different temperature ranges. Upon reaching one or more thresholds, signals are generated which indicate the need to replace the heat-transfer fluid.

## Claims

### Claim 1

Machine for testing thermal resistance of plastic materials, comprising:
a tank (2) configured, in use, to be filled with a heat-transfer fluid,
means (11) for heating the heat-transfer fluid,
a temperature sensor (13) configured to generate, in use, a temperature signal (T) of the heat-transfer fluid, having a value, and
a control unit (4) for monitoring degradation of the heat-transfer fluid, the control unit configured to receive the temperature signal (T) and to calculate a degradation index (N) of the heat-transfer fluid based on the temperature signal.

### Claim 2 (depends on 1)

The test machine according to claim 1, wherein the control unit (4) is configured to count a plurality of partial heating times (n1-n4), each partial heating time being related to a heating time of the heat-transfer fluid in an own temperature range from a plurality of temperature ranges, the control unit (4) comprising a plurality of memory elements (41), each memory element being configured to store a respective partial heating time, the control unit being configured to calculate the degradation index as the weighted sum of the plurality of partial heating times.

### Claim 3 (depends on 2)

The test machine according to claim 2, wherein the control unit (4) is a microcontroller and comprises a processor (35) and a volatile memory unit (38) including the plurality of memory elements (41), the processor (35) being configured to receive (52) the value of the temperature signal (T), read (56) the partial heating time stored in the memory element associated with the temperature range corresponding to the value of the temperature signal, update (58) the stored partial heating time, read (60) the partial heating times of all of the memory elements, and calculate (62) the degradation index by adding the partial heating times.

### Claim 4 (depends on 2)

The test machine according to claim 2, wherein the degradation index is calculated according to the equation:
N
=
∑
i
=
1
k

n
i
N
i
wherein k is the number of temperature ranges, ni is the corresponding partial heating time and Ni is a maximum degradation value associated with each temperature range.

### Claim 5 (depends on 1)

The test machine according to claim 1, wherein the control unit (4) is configured to generate warnings (70; 72) when the degradation index of the heat-transfer fluid reaches preset threshold values.

### Claim 6 (depends on 3)

The test machine according to claim 3, wherein the control unit (4) comprises a non-volatile memory (39) configured to periodically store the partial heating times.

### Claim 7

A method for determining degradation of a heat-transfer fluid in a machine (1) for testing thermal resistance characteristics of plastic materials, the test machine having means for heating the heat-transfer fluid, the method including:
acquiring (52) a temperature signal (T) of the heat-transfer fluid having a value, and
calculating (54-62) a degradation index of the heat-transfer fluid on the basis of the temperature signal.

### Claim 8 (depends on 7)

The method according to claim 7, wherein calculating a degradation index comprises:
determining (54) a temperature range associated with the value of the temperature signal (T) from a plurality of temperature ranges,
updating (58) a partial heating time related to the selected temperature range,
acquiring (60) partial heating times for each temperature range in the plurality of temperature ranges, and
calculating (62) a weighted sum of the partial heating times.

### Claim 9 (depends on 8)

The method according to claim 8, wherein the calculating the degradation index phase (62) uses equation:
N
=
∑
i
=
1
k

n
i
N
i
wherein k is the number of temperature ranges, ni is the partial heating time in each temperature range and Ni is a maximum degradation value associated with each temperature range.

### Claim 10 (depends on 8)

The method according to claim 8, including storing (58) the updated partial heating time by volatile memory writing, wherein acquiring (60) partial heating times for each temperature range comprises reading a plurality of cells (41) of a volatile memory (38) each associated with a respective temperature range in the plurality of temperature ranges.

### Claim 11 (depends on 7)

The method according to claim 7, also including generating (70, 72) a warning when the degradation index of the heat-transfer fluid reaches preset threshold values.

### Claim 12 (depends on 8)

The method according to claim 8, wherein acquiring (52) a temperature signal and calculating (54-62) a degradation index are carried out periodically with a monitoring time interval (Δt) and updating the partial heating time comprises acquiring a previous stored partial heating time and adding the monitoring time interval.

### Claim 13 (depends on 7)

The method according to claim 7, further comprising periodically saving (78) the partial heating times in a non-volatile memory (39).

### Claim 14 (depends on 7)

The method according to claim 7, further including:
acquiring experimental gel-time values associated with two experimental heating temperatures of the heat-transfer fluid,
using the experimental gel-time values as maximum degradation values associated to the respective temperature ranges including both experimental temperatures, and
calculating further maximum degradation values as linear interpolations of the experimental gel-time values.

### Claim 15 (depends on 7)

A program product for a processor configured to implement, when loaded onto processing means, the method according to claim 7.