Adhesive Melter and Method Having Predictive Maintenance for Exhaust Air Filter

• US 20150027546A1
• Filed: 07/29/2013
• Published: 01/29/2015
• Est. Priority Date: 07/29/2013
• Status: Active Grant

• Current Assignee: Nordson Corporation
• Original Assignee: Nordson Corporation
• Inventors: Bondeson, Benjamin J., Clark, Justin A.
• Granted Patent: US 9,574,714 B2
• Time in Patent Office: Days
• US Class Current: 137/1
• CPC Class Codes: B05C 11/00 Component parts, details or accessories not specifically provided for in groups B05C1/00 - B05C9/00 means for manipulating or holding work B05C13/00; enclosures for apparatus, booths B05C15/00; spray booths B05B16/00
• CPC Class Codes: B05C 11/1042 provided with means for heating or cooling the liquid or other fluent material in the supplying means upstream of the applying apparatus
• CPC Class Codes: B29B 13/022 Melting the material to be shaped
• CPC Class Codes: B65G 53/16 Gas pressure systems operating with fluidisation of the materials
• CPC Class Codes: B65G 53/60 Devices for separating the materials from propellant gas
• CPC Class Codes: B65G 53/66 Use of indicator or control devices, e.g. for controlling gas pressure, for controlling proportions of material and gas, for indicating or preventing jamming of material controlling the flow of coal firing systems C21B5/003
• CPC Class Codes: F17D 3/00 Arrangements for supervising or controlling working operations
• CPC Class Codes: Y10T 137/0318 Processes
• CPC Class Codes: Y10T 137/8158 With indicator, register, recorder, alarm or inspection means

Abstract

An adhesive melter and a method for operating the melter enables predictive maintenance of an exhaust air filter used to remove pressurized air flow that delivers solid adhesive particulate from a fill system into the melter. To this end, the fill system repeatedly actuates to refill a receiving space, and a controller monitors a duration of each fill system cycle. When changes in a calculated average duration of a plurality of fill system cycles exceed a maintenance threshold, an alert is emitted at a user interface to prompt maintenance or replacement of the exhaust air filter before a complete shutdown of the fill system is caused by clogging of the exhaust air filter. Consequently, unplanned downtimes caused by clogged exhaust air filters in the adhesive melter can be minimized, regardless of any variable conditions occurring at the melter.

Claims

1. A method for operating an adhesive melter including a receiving space, a fill system configured to refill the receiving space, and an exhaust air filter, the method comprising:

repeatedly actuating the fill system to perform a fill system cycle that refills the receiving space with solid adhesive particulate delivered with a pressurized air flow into the receiving space, the pressurized air flow being exhausted from the receiving space through the exhaust air filter;

monitoring a duration of each of the fill system cycles;

calculating an average duration for a plurality of the fill system cycles;

detecting a change in the average duration for the fill system cycles; and

emitting an alert with a user interface operatively coupled to the adhesive melter if the detected change exceeds a maintenance threshold that is indicative of the exhaust air filter becoming clogged and requiring maintenance.

2. The method of claim 1, wherein the adhesive melter further includes a level sensor at the receiving space, and repeatedly actuating the fill system to perform a fill system cycle further comprises:

repeatedly sensing with the level sensor a fill level of adhesive located within the receiving space;

starting operation of the fill system to deliver solid adhesive particulate and pressurized air flow into the receiving space when the level sensor senses that the fill level has dropped below a refill threshold; and

stopping operation of the fill system when the level sensor senses that the fill level has exceeded a full fill threshold.

3. The method of claim 2, wherein monitoring the duration of each of the fill system cycles further comprises:

for a selected fill system cycle, detecting a first time when the level sensor senses that the fill level has dropped below the refill threshold and a second time when the level sensor senses that the fill level has exceeded the full fill threshold;

calculating a difference between the first time and the second time, the difference corresponding to the duration of the selected fill system cycle; and

repeating the detecting and calculating a difference steps for each of the fill system cycles.

4. The method of claim 3, wherein the adhesive melter includes a controller operable to perform the calculating and detecting a change steps, and the emission of the alert is initiated by the controller based solely on data from the level sensor and the monitoring of the durations of each of the fill system cycles.

5. The method of claim 1, wherein detecting a change in the average duration for the fill system cycles further comprises:

identifying a predetermined number of most recently calculated average durations for a plurality of the fill system cycles;

statistically analyzing the predetermined number of most recently calculated average durations over time to determine a trend line for the most recently calculated average durations; and

calculating a slope of the trend line to determine the change in the average duration for the fill system cycles.

6. The method of claim 1, wherein the fill system is configured to shut down if the average duration for a plurality of the fill system cycles exceeds a maximum flow threshold, and emitting the alert further comprises:

initiating the alert with the user interface before the average duration for the plurality of the fill system cycles exceeds the maximum flow threshold, thereby providing a period of time for maintenance of the exhaust air filter before shut down of the fill system; and

continuing to emit the alert with the user interface until either (i) maintenance is performed on the exhaust air filter, or (ii) the fill system shuts down.

7. The method of claim 1, further comprising:

statistically analyzing the duration of each of the fill system cycles to identify individual data outliers that indicate a change in the average duration for reasons unrelated to exhaust air filter clogging; and

discarding the individual data outliers before calculating the average duration and detecting a change in the average duration for the fill system cycles.

8. The method of claim 1, wherein after maintenance or replacement of the exhaust air filter has occurred, the method further comprises:

evaluating the duration of each of the fill system cycles until the average duration for a plurality of fill system cycles stabilizes after an initial time period; and

discarding data on the durations of the fill system cycles for the initial time period before detecting a change in the average duration for the fill system cycles.

9. The method of claim 1, wherein calculating the average duration for a plurality of the fill system cycles further includes calculating an average daily fill time for each day the adhesive melter is operated, and

wherein detecting a change in the average duration for the fill system cycles further includes selecting a number of most recent average daily fill times and statistically analyzing the number of most recent average daily fill times to identify a trend line having a slope which corresponds to the change in the average duration for fill system cycles over the number of most recent average daily fill times.

10. An adhesive melter, comprising:

a receiving space configured to receive a supply of solid adhesive particulate that is to be melted by a heater unit;

a fill system coupled to said receiving space and performing fill system cycles that refill said receiving space with solid adhesive particulate delivered with a pressurized air flow;

an exhaust air filter communicating with said fill system and said receiving space, said exhaust air filter exhausting the pressurized air flow from said receiving space during fill system cycles;

a controller operatively coupled to said fill system and working during operation of the adhesive melter to repeatedly actuate said fill system, to monitor a duration of each fill system cycle performed by said fill system, to calculate an average duration for a plurality of the fill system cycles from the durations monitored by said timer, to detect a change in the average duration for the fill system cycles, and to emit an alert with a user interface if the detected change exceeds a maintenance threshold indicative of said exhaust air filter becoming clogged and requiring maintenance.

11. The adhesive melter of claim 10, further comprising:

a level sensor located at said receiving space, said level sensor repeatedly sensing a fill level of adhesive located within said receiving space, wherein said controller actuates said fill system by starting operation of said fill system when said level sensor senses that the fill level has dropped below a refill threshold and by stopping operation of said fill system when said level sensor senses that the fill level has exceeded a full fill threshold.

12. The adhesive melter of claim 11, wherein said receiving space is at least partially defined by a sidewall, and said level sensor further comprises:

a plate element;

an electrically driven electrode located on said plate element; and

a ground electrode located on said plate element and adapted to be electrically connected to said sidewall such that said sidewall forms at least a portion of said ground electrode, said ground electrode operatively connected to said electrically driven electrode for measuring a dielectric capacitance of air and adhesive acting as a dielectric between said driven and ground electrodes, the dielectric capacitance varying with the fill level of the adhesive such that said controller can monitor when said level sensor senses that the fill level has dropped below the refill threshold or has exceeded the full fill threshold.

13. The adhesive melter of claim 11, wherein said controller actuates the emission of the alert with the user interface based solely on data received from said level sensor.

14. The adhesive melter of claim 10, wherein said controller detects a change in the average duration for the fill system cycles by working to identify a predetermined number of most recently calculated average durations for a plurality of the fill system cycles, to statistically analyze the predetermined number of most recently calculated average durations over time to determine a trend line for the most recently calculated average durations, and to calculate a slope of the trend line to determine the change in the average duration for the fill system cycles.

15. The adhesive melter of claim 10, wherein the fill system is configured to shut down if the average duration for a plurality of fill system cycles exceeds a maximum flow threshold, and wherein said controller actuates the emission of the alert with the user interface before the average duration for the plurality of fill system cycles exceeds the maximum flow threshold, to provide a period of time for maintenance of said exhaust air filter before shut down of the fill system.