TEMPERATURE RECORDING SYSTEMS

Manually filled Logsheet

Reefer container (Front)

PARTLOW RECORDER

PARTLOW CHART (Blank)

PARTLOW CHART EXERCISE

• Introduced as a back up for manual recording of temperatures

• Works as a stand alone unit not requiring external power supply

• Mechanical clock winding mechanism provides drive for a rotating chart.

• Provides continuous temperature recording for 31 days irrespective of power supply availability, whether container is empty or cargo loaded.

GENESIS

• Provides only return temperature recording• Can be manually fudged – not 100% foolproof• Since it is a mechanical device, there is a little

amount of sluggishness and hunting.• Prone to damage from external elements even

though located in a protective enclosure• Needs regular calibration

Disadvantages

• Subsequently replaced with Electronic datarecorder.

• However some container owners still persist with Partlow Chart as it provides a readily readable record of temperature.

Location of Partlow Mechanism and Sensor

Partlow Chart Mechanism

• Stylus contact on chart is not correct

• System running with choked expansion valve passage or less refrigerant charge

Fault Finding from Partlow Charts

Fault Finding from Partlow Charts

• Excessive Moisture in the Cargo Space

• Compressor Tripped

1. Cargo Temp Setpoint: +8ººC

2. Date and Time of Plugging on board: 2nd noon

3. Temp at the time of plugging: 14ººC

4. Defrost Interval; 6 hours

5. Temp rise during Defrost: 3ººC

6. Start of Power Breakdown: 5th noon

7. Power restored: 5th midnight

8. Temp rise during power breakdown: 8ººC

9. Container Unplugged: 14th noon

Partlow Chart Exercise-Chilled Cargo

Draw a Partlow Chart based on the foll: data

Identify +8ººC on the Chart and draw a light circle representing Setpoint

Identify and mark 2nd noon and 14ººC to identify the time and temp at plugging

Draw the curve to reduce the temp to 10ººC in 6 hrs Show a gradual increase of temp to 13ººC for max

period of 2 hrsAt the end of 2 hrs show a sharp drop of temp to

10ººC in about 1 hrRepeat the Defrost cycle after every 6 hrs.From 5th noon till 5th midnight show a gradual rise

of temp upto 18ººC

Partlow Chart Exercise-Chilled Cargo SOLUTION

After power is restored at 5th midnight, show a rapid fall in temp upto 12ººC in 6 hours when the next defrost cycle starts.

Repeat the defrost cycle for 2 hours showing temp rise of 3ººC

After the next defrost cycle show temp fall upto 10ººC in about 1 hr

Repeat the cooling and defrost cycle till 14th noon when the container is unplugged

Thereafter show a gradual rise in temp.

Partlow Chart Exercise-Chilled Cargo SOLUTION Contd.

1. Cargo Temp Setpoint: -15ººC 2. Date and Time of Plugging on board: 18th noon3. Temp at the time of plugging: -8ººC 4. Defrost Interval: 24 hours5. Temp rise during Defrost: 4ººC 6. Start of Power Breakdown: 22nd noon7. Power restored: 23rd midnight8. Temp rise during power breakdown: 5ººC 9. Container Unplugged: 30th noon

Partlow Chart Exercise-Frozen CargoDraw a Partlow Chart based on the foll: data

Identify -15ººC on the Chart and draw a light circle representing Setpoint

Identify and mark 18th noon and -8ººC to identify the time and temp at plugging

Draw the curve to reduce the temp to -15ººC in 3 hrsMaintain the same temp for about 24 hrs till the start

of the first defrost cycle Show a gradual increase of temp to -11ººC for max

period of 2 hrsAt the end of 2 hrs show a sharp drop of temp to -

15ººC in about 1 hrRepeat the Defrost cycle after every 24 hrs.From 22nd noon till 23rd noon show a gradual rise of

temp upto -10ººC

Partlow Chart Exercise-Frozen Cargo SOLUTION

After power is restored at 23rd noon, show a rapid fall in temp upto -15ººC in 2 hours and maintain it till the next defrost cycle starts.

Repeat the defrost cycle for 2 hours showing temp rise of 3 ººC

After the next defrost cycle show temp fall upto -15ººC in about 1 hr

Repeat the cooling and defrost cycle till 30th noon when the container is unplugged

Thereafter show a gradual rise in temp.

Partlow Chart Exercise-Frozen Cargo SOLUTION Contd.

SOLUTION

For Chilled cargoes, the minimum temp recorded on Partlow Chart is 2-3ººC more than the Setpoint Temp whereas for Frozen cargoes, the minimum temp goes as low as the Setpoint Temp. WHY?

The max. Defrosting time is 2 hrs. WHY?For Chilled cargoes, the rise is temp is faster than for

frozen cargoes - both during defrosting time and also during power breakdown. WHY?

Defrosting interval is 6 hrs and 24 hrs respectively for chilled cargoes and frozen cargoes. WHY?

Points to PONDER

• Mechanical hand winding mechanism replaced by battery

• Design with 2 sensors used for non-transport applications.

• Electronic Partlow Recorders

IMPROVEMENTS ON PARTLOW CHARTS

PARTLOW CHART (Used)

LOCATION OF PARTLOW SENSOR

• All Containers are equipped with Electronic Datarecorders. These provide continuous recording of the temperatures and events occuring in the machinery.

• It is a tamperproof device and the recorded data is accepted as evidence in the court of law.

Information recorded in the Datacorder

• In many instances, shipstaff have been pulled up for not recording power breakdowns – whether planned or unplanned.

• This happens, particularly, if any cargo damage is noticed at the consignee’s end, when the datarecorder has recorded a power interruption, but same has not been logged by the shipstaff.

• The Datacorder is a “Black Box”. Nothing escapes its notice. It records even the slightest variation in temperature – minute by minute.

• BE CAREFUL – BIG BROTHER IS WATCHING!

Data recorded in Datacorder – Good Cargo

Power Breakdown

Power Interruption and Back up Battery removed

Frequent Power Interruptions

Raw Data – Minute by Minute Recording

Data from Carrier Datacorder

Data from Carrier Datacorder Contd.

Data from Carrier Datacorder

Data from Thermoking Recorder

RECORDED DATA

Temperature Recorders inside Cargo

LOCATION OF CARGO PROBES (USDA)

Cargo probes Recorded Data

Remote monitoring modem

FOUR WIRE SYSTEM