GB2293703A - Mains failure protection for refrigerated loads - Google Patents
Mains failure protection for refrigerated loads Download PDFInfo
- Publication number
- GB2293703A GB2293703A GB9419429A GB9419429A GB2293703A GB 2293703 A GB2293703 A GB 2293703A GB 9419429 A GB9419429 A GB 9419429A GB 9419429 A GB9419429 A GB 9419429A GB 2293703 A GB2293703 A GB 2293703A
- Authority
- GB
- United Kingdom
- Prior art keywords
- timer
- protection device
- supply
- mains
- refrigeration unit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 241000283074 Equus asinus Species 0.000 claims abstract description 27
- 238000005057 refrigeration Methods 0.000 claims abstract description 24
- 239000007858 starting material Substances 0.000 claims abstract description 14
- 238000000034 method Methods 0.000 claims abstract description 8
- 238000012544 monitoring process Methods 0.000 claims description 13
- 230000001934 delay Effects 0.000 claims description 2
- 230000000977 initiatory effect Effects 0.000 claims description 2
- 238000012802 pre-warming Methods 0.000 claims description 2
- 230000001960 triggered effect Effects 0.000 claims description 2
- 230000000694 effects Effects 0.000 description 2
- 230000003111 delayed effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 235000013611 frozen food Nutrition 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
- B60H1/00—Heating, cooling or ventilating [HVAC] devices
- B60H1/32—Cooling devices
- B60H1/3204—Cooling devices using compression
- B60H1/3225—Cooling devices using compression characterised by safety arrangements, e.g. compressor anti-seizure means or by signalling devices
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
- H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
- H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
- H02J9/08—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems requiring starting of a prime-mover
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2310/00—The network for supplying or distributing electric power characterised by its spatial reach or by the load
- H02J2310/40—The network being an on-board power network, i.e. within a vehicle
- H02J2310/46—The network being an on-board power network, i.e. within a vehicle for ICE-powered road vehicles
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Power Engineering (AREA)
- Devices That Are Associated With Refrigeration Equipment (AREA)
- Air-Conditioning For Vehicles (AREA)
Abstract
When a vehicle or trailer carrying a refrigerated load is parked, a refrigeration unit is powered from the mains supply, but if the mains supply fails a control circuit powered by the vehicle battery starts an on board donkey engine which then energises the refrigeration unit. Mains failure de-energises a sensing relay R1 having N.C. contacts R1 in the battery supply to the control circuit. Following a delay determined by a timer (T1 - provided in case the failure is of only short duration), glow plugs of the donkey engine are energised for a period determined by a timer T2, T2A and then a starter motor solenoid is energised for a period determined by a timer T3. Starter motor energisation is terminated if a detector circuit (Fig. 3) senses a satisfactory supply current from the donkey engine, but if the timer T3 times out without a satisfactory supply current being established, the starting process is re-initiated without the delay of timer (T1). A relay (R3, Fig. 4) prevents power being supplied from a restored mains supply while the donkey engine is running. The mains supply is reconnected after a delay, provided by a further timer, following operation of a reset switch (R2/2) in the vehicle cab. <IMAGE>
Description
Mains Failure Protection Device for
Refrigerated Loads
This invention relates to a device for protecting a refrigerated load on a parked vehicle or trailer against failure of the electrical mains supply.
When a vehicle or trailer having a refrigerated enclosure for a load such as frozen food is being driven, the refrigeration unit is in effect powered by the operational vehicle engine. When such a vehicle is parked overnight in a depot, refrigeration of the load is maintained by powering the refrigeration unit from the local electrical mains supply. Typically, for parking at a site where the electrical mains supply is not available, the refrigeration unit can, in effect, be powered from an on-board donkey engine, typically a diesel engine. Use of the local electrical mains supply is obviously preferable for overnight parking, and it is usual to park refrigerated vehicles overnight at protected sites when the mains supply is available.
However, if the electrical mains supply fails overnight, or an electrical failure occurs on board such as tripping out of the electric motor of the refrigeration unit, it is easily possible for the entire load to be unremediably damaged, resulting in a total loss of goods often worth many thousands of pounds.
An aim of the present invention is to provide a solution to this problem.
According to the invention, there is provided a mains failure protection device for a refrigerated load on board a parked vehicle or trailer, comprising an electrical circuit for monitoring the electrical supply to the refrigeration unit, and an electrical circuit powered from the vehicle battery for controlling the starting of the donkey engine of the refrigeration unit responsively to the monitoring circuit detecting an electrical supply failure.
The supply failure detected may, for example, be due to a power cut in the mains supply, a short circuit, an overload trip, or inadvertent switching off of the mains supply.
Preferably, a second monitoring circuit is provided, in particular for monitoring the electrical output derived from the donkey engine, enabling the circuitry to be at least partially reset once this electrical output is established.
The usual donkey engine provided on board a refrigerated vehicle or trailer is a diesel engine, which requires pre-warming by means of glow plugs prior to energisation of a starter motor relay. Preferably, therefore, the control circuit includes a timer determining the period for which the glow plugs are activated, and the starter motor relay is only energised when this timer times out, switching off the glow plugs. A second timer then controls energisation of the starter motor relay.
However, if the second monitoring circuit detects a satisfactory electrical output, the second timer is triggered in advance of timing out, although in either case de-energising the starter motor relay. Most preferably, if the second timer times out without a satisfactory supply current being established, resetting is effected at least to the extent necessary to enable the control circuit to re-initiate the starting process for the donkey engine. If the first timer also delays initiation of this starting process following a failure of the power supply, i.e. to allow for the possibility that the failure is of short duration only, then any necessary re-initiation of the starting process does not include this initial delay.
Preferably, means are also provided in the control circuit for preventing power being supplied from the mains supply, e.g. in the event of power restoration, while the donkey engine is running to power the refrigeration unit.
A cab control preferably enables the donkey engine to be switched off by fully resetting the control circuit, before reconnecting the mains power supply to the refrigeration unit, as and when appropriate.
An embodiment of protection device in accordance with the invention is now described by way of example with reference to the accompanying drawings, in which:
Figure 1 is a basic circuit diagram of the complete device;
Figure 2 shows the circuit of a supply current monitor;
Figure 3 shows the circuit of an engine-running detector;
and
Figure 4 shows a control circuit.
It should first be understood that a refrigerated vehicle or trailer conventionally includes means for operating the refrigeration unit by power effectively derived from running of the driving engine, means for operating the refrigeration unit either from the mains power supply or by power effectively derived from an on-board donkey engine when the vehicle is parked, and control circuitry, including a cab control, for controlling these procedures. The device in accordance with the present invention, and especially control circuitry therefor, to some extent makes use of the existing on-board facilities.
Figure 1 enables the basic principles of the device in accordance with the invention to be understood.
If, when the vehicle is parked and the refrigeration unit is being powered by the local mains supply, a mains failure (or functionally equivalent failure) occurs, then the illustrated control circuit is supplied with power from the vehicle battery. Following a delay determined by timer T1 (provided in case the failure is of very short duration), the glow plugs for the on-board donkey engine are energised for a period determined by timer T2,
T2A, following which timer T3 controls energisation of a solenoid for the starter motor of the donkey engine.
Normally open relay contacts T1/2, T2/2 and T2A/2 ensure that the glow plugs and the starter motor solenoid cannot be energised at the same time and that the solenoid energisation will immediately follow timing out of the glow plugs by timer T2A. Contact T3/1 closes the starter motor energising circuit.
Relay R1, forming part of a circuit monitoring the mains supply current to the refrigeration unit, controls supply of power, via normally closed contact R1, to the abovedescribed timer controlled circuit.
In the cab, a reset switch R2/1 on a control box, and controllable by relay R2, enables the system to be reset when mains power is restored. Reconnection of the mains power is delayed by timer T4. The circuit to relay R1 also includes an O/L switch operated in the event of a current overload. Relay R2 holds the relay R1 deenergised when power is being derived from the donkey engine, thereby to prevent reconnection of the mains supply (restored or not) to the refrigeration unit except by operation of the reset switch in the cab.
Figure 2 shows one possible embodiment of circuit for monitoring the supply current to the refrigeration unit.
Normally energised relay R1 is de-energised if the supply current fails, closing contact Rl/l (Figure 4) to power up the control circuit of Figure 4 from the on-board vehicle battery.
Figure 3 shows one possible embodiment of circuit for monitoring the current supply to the refrigeration unit when the donkey engine is running. This circuit provides a signal input to timer icib of the control circuit of
Figure 4, terminating the running time period of the starter motor for the donkey engine if a satisfactory supply current is detected.
Figure 4 shows one possible embodiment of control circuit.
On the left-hand side are shown relay R2, which is operable to reset the system by use of a reset switch R2/2 in the vehicle cab, and relay R3, which is operative to prevent mains supply current being fed to the refrigeration unit while the donkey engine is running (see contact R3/1 in
Figure 2).
Timer lcia controls powering of the glow plugs for a predetermined period set by RV1. When this timer times out, timer lcib initiates operation of the starter motor for the donkey engine by energising relay R5. The part of the circuit incorporating the transistor Q4 is associated with the vehicle cab control, which has a press button for starting the donkey engine manually and a press button which puts the circuitry of Figures 2, 3 and 4 into an active condition, ready to initiate operation of the donkey engine if there is a power failure or equivalent failure when the refrigeration unit is being operated from the mains supply.
Various modifications of the above described and illustrated arrangement are possible within the scope of the invention hereinbefore defined.
Claims (11)
1. A mains failure protection device for a refrigerated load on board a parked vehicle or trailer, comprising an electrical circuit for monitoring the electrical supply to the refrigeration unit, and an electrical circuit powered from the vehicle battery for controlling the starting of the donkey engine of the refrigeration unit responsively to the monitoring circuit detecting an electrical supply failure.
2. A protection device according to claim 1, which is able to detect a poser cut in the mains supply, a short circuit, an overload trip, andVor inadvertent switching off of the mains supply.
3. A protection device according to claim 1 or claim 2, including a second monitoring circuit for monitoring the electrical output derived from the donkey engine, enabling the circuitry to be at least partially reset once this electrical output is established.
4. A protection device according to any of claims 1 to 3, wherein the donkey engine provided on board the refrigerated vehicle or traIler is a diesel engine, which requires pre-warming by means of glow plugs prior to energisation of the starter motor relay, and wherein the control circuit includes a timer determining the period for which the glow plugs are activated, and the starter motor relay is only energised when this timer times out, switching off the glow plugs.
5. A protection device accordin' to claim , wherein a second timer controls energisation of the stater motor relay.
6. A protection device according to claim 5, wherein, if the second monitoring circuit detects a satisfactory electrical output, the second timer is triggered in advance of timing out, thereby to de-energise the starter motor relay.
7. A protection device according to claim 5 or claim 6, wherein, if the second timer times out without a satisfactory supply current being established, resetting is effected at least to the extent necessary to enable the control circuit to re-initiate the starting process for the donkey engine.
8. A protection device according to claim 7, wherein, if the first timer also delays initiation of the starting process following a failure of the power supply, then any necessary re-initiation of the starting process does not include this initial delay.
9. A protection device according to any of claims 1 to 8, including means in the control circuit for preventing power being supplied from the mains supply, in the event of power restoration, while the donkey engine is running to power the refrigeration unit.
10. A protection device according to any of claims 1 to 9, wherein a cab control enables the donkey engine to be switched off by fully resetting the control circuit, before reconnecting the mains power supply to the refrigeration unit.
11. A mains failure protection device for 2 refrigerated load on board a parked vehicle or traIler, substantially as hereinbefore described with preference to the accoJnyinQ drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9419429A GB2293703A (en) | 1994-09-27 | 1994-09-27 | Mains failure protection for refrigerated loads |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9419429A GB2293703A (en) | 1994-09-27 | 1994-09-27 | Mains failure protection for refrigerated loads |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9419429D0 GB9419429D0 (en) | 1994-11-09 |
| GB2293703A true GB2293703A (en) | 1996-04-03 |
Family
ID=10761948
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9419429A Withdrawn GB2293703A (en) | 1994-09-27 | 1994-09-27 | Mains failure protection for refrigerated loads |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2293703A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2350947A (en) * | 1998-06-11 | 2000-12-13 | Potomac Capital Invest Corp | Interface between load and power sources; utility meter collar with interface |
| US6188145B1 (en) | 1998-06-11 | 2001-02-13 | Potomac Capital Investment Corp. | Meter collar with interface for connecting on-site power source, and the interface itself |
| US8590330B2 (en) | 2010-06-03 | 2013-11-26 | Thermo King Corporation | Electric transport refrigeration unit with temperature-based diesel operation |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1538232A (en) * | 1975-03-25 | 1979-01-17 | Agie Ag Ind Elektronik | Apparatus for supplying electrical energy to a load |
| GB2164433A (en) * | 1984-09-12 | 1986-03-19 | Carrier Corp | Automatic emergency engine starting system |
| EP0441525A2 (en) * | 1990-02-09 | 1991-08-14 | Sanden Corporation | Safety mechanism for vehicle container refrigerator |
| US5268850A (en) * | 1991-05-07 | 1993-12-07 | Skoglund Robert A | Automatic power-failure and auxiliary generator control |
-
1994
- 1994-09-27 GB GB9419429A patent/GB2293703A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1538232A (en) * | 1975-03-25 | 1979-01-17 | Agie Ag Ind Elektronik | Apparatus for supplying electrical energy to a load |
| GB2164433A (en) * | 1984-09-12 | 1986-03-19 | Carrier Corp | Automatic emergency engine starting system |
| EP0441525A2 (en) * | 1990-02-09 | 1991-08-14 | Sanden Corporation | Safety mechanism for vehicle container refrigerator |
| US5268850A (en) * | 1991-05-07 | 1993-12-07 | Skoglund Robert A | Automatic power-failure and auxiliary generator control |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2350947A (en) * | 1998-06-11 | 2000-12-13 | Potomac Capital Invest Corp | Interface between load and power sources; utility meter collar with interface |
| US6188145B1 (en) | 1998-06-11 | 2001-02-13 | Potomac Capital Investment Corp. | Meter collar with interface for connecting on-site power source, and the interface itself |
| US6376937B1 (en) | 1998-06-11 | 2002-04-23 | Potomac Capitol Investment Corp. | Meter collar with interface for connecting on-site power source, and the interface itself |
| GB2350947B (en) * | 1998-06-11 | 2004-03-17 | Potomac Capital Invest Corp | Meter collar with interface for connecting on-site power source,and the interface itself |
| US8590330B2 (en) | 2010-06-03 | 2013-11-26 | Thermo King Corporation | Electric transport refrigeration unit with temperature-based diesel operation |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9419429D0 (en) | 1994-11-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |