JPS6222061B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a centralized temperature control device for a refrigeration system, such as a plurality of refrigeration and air conditioning equipment.

Conventionally, such a centralized temperature control device, as illustrated in FIG.
F ₁ is provided with an in-case temperature detector S ₁ , a refrigerant throttle valve V ₁ in a refrigeration cycle (not shown), a control device for this throttle valve V ₁ (for example, an actuator that opens and closes valve V ₁ ) VC _{1 , and a similar open/close controller VC 1} . Some open show cases include a plurality of open show cases F ₂ and F ₃ arranged in parallel, and a central control device C commonly connected to these open show cases. However, in such a configuration, the open show cases F ₁ , F ₂ , F ₃ . There are also problems in terms of countermeasures.

As a conventional example, as shown in Fig. 2, if a transmitter T is inserted, the total length of the wiring will be shortened, and the disadvantages of the case shown in Fig. 1 described above will be eliminated. With widely used minicomputers and microcomputers, the transmission processing time is long (for example, several minutes to several tens of minutes when the number of open display cases is large), which poses a practical problem.

Furthermore, in any of these cases, the refrigeration equipment is not always accurately controlled to the intended temperature, and furthermore, if the central control unit C breaks down, it will be completely out of hand. .

Therefore, in order to solve these problems, the inventor of the present invention, as a result of research, installed a terminal device in each refrigeration device to control each refrigeration device by a temperature setting device provided in each refrigeration device. In addition, a central control device is commonly connected to these devices via a transmitter, and this central control device periodically controls the temperature setting device of any of the refrigeration devices and the temperature detection of the refrigeration device at appropriate times. The present invention was completed based on the finding that each of the above-mentioned problems could be solved by reading the output of the temperature setting device and correcting the output of the temperature setting device based on the read value. It is.

Therefore, the main purpose of the present invention is to prevent the total length of wiring from becoming long, to eliminate the problem of transmission processing time even if the computer in the central control device is small and slow, and to automatically control each refrigeration device to the intended temperature. The refrigeration system can be controlled accurately, and even if the central control device fails, the control of the refrigeration equipment will not stop immediately.
The present invention aims to provide a centralized temperature control device for multiple refrigeration devices.

Other objects and features of the invention will become clearer from the following more detailed description.

An embodiment of the present invention will be described below with reference to FIG. In this example, a frozen/refrigerated open case is used as the refrigeration system.
This invention is not limited to this embodiment.

F ₁ , F ₂ and F ₃ are each known refrigerated open case.

S ₁ , S ₂ and S ₃ are in-case temperature detectors provided in the open case cases F ₁ , F ₂ and F ₃ , respectively.

V ₁ , V ₂ and V ₃ are refrigeration capacity control devices provided in the open shower cases F ₁ , F ₂ and F ₃ , respectively, and in this embodiment are refrigerant throttle valves of a refrigeration cycle (not shown). This refrigerating capacity control device may be any other known means.

VC ₁ , VC ₂ and VC ₃ are throttle valves V ₁ , V ₂ respectively
and a valve control device (such as an actuator) that controls the opening of _V3 .

TE ₁ , TE ₂ and TE ₃ are terminal devices connected to the case F ₁ , F ₂ and F ₃ , respectively.

The terminal device TE ₁ includes a manual temperature setting device 1, a variable controller 3 into which the output of the temperature setting device 1 is input via a switching means 2, and a variable controller 3 capable of holding the output of this controller 3, and a valve control device VC ₁ . It consists of a known hold circuit 4 connected to input the output, and a switching means 5 interposed to input the output of the temperature sensor _S1 to the controller 3. Terminal device TE ₂ ,
It should be understood that TE ₃ has a similar configuration. Note that the controller 3 is a known differential amplifier that includes at least a variable gain function and a variable bias function. Note that the variable function may include a variable response speed function.

6 is an ambient air condition detector, which in this embodiment is a temperature detector outside the case.

C is a central control device, and in this embodiment, a known minicomputer or microcomputer is used.

T ₁ and T ₂ are central control device C and each terminal device
This is a known transmitter interposed between TE ₁ , TE ₂ and TE ₃ , with T ₁ connected to the signal input/output terminal of each terminal device, and T ₂ connected to T ₁ of each of these terminal devices. connected in common.

Further, in response to a timely periodic command from the control device C, the switching means 2 and 5 of one of the terminals TE ₁ , TE ₂ or TE ₃ are switched so that the output of the detector S ₁ , S ₂ or S ₃ and the corresponding It is connected to read the output of the setting device 1 and to hold the output contents of the controller 3 at that time in a hold circuit 4. At the time of this switching, the control device C controls the setting device 1, the detector 6, and the corresponding detector S ₁ , S ₂ or
It is assumed that a system program has been input in advance to input any of the outputs of S3 to control the aforementioned variable functions of the variable controller ₃ . For example, when frost forms on an evaporator (not shown) and the output value of the corresponding detector S ₁ , S ₂ or S ₃ does not become lower than the setting value of the setting device 1, the system program If the bias value of controller 3 is changed to have the same effect as if the setting value of is lowered, or if the output value of detector S ₁ , S ₂ or S ₃ changes drastically up and down. The contents include changing the gain of the controller 3 or changing the response speed.

Next, the operation of the above-mentioned configuration will be described.

Normally, for example, in the terminal device TE ₁ , the outputs of the setting device 1 and the detector S ₁ are input to the controller 3 as shown in the figure, and the valve control device VC 1 is controlled by the output corresponding to the difference, and the valve control device VC ₁ is controlled by the output corresponding to the difference. ₁ opening so that the output of controller 3 is zero, that is, detector S ₁
The function of the well-known servo system is controlled so that the output value is the same as the setting value of the setting device 1.

However, if the performance of the refrigeration cycle changes due to frost formation on the evaporator of the refrigeration cycle (not shown), or if the condition of the outside air changes, the setting device 1 may be further manually controlled, or the controller Unless the gain of step 3 is changed, the temperature inside the case _F1 cannot be maintained at the desired temperature.

Therefore, at appropriate times (for example, every 5 to 30 minutes),
In response to a command from the control device C, the switching means 2 and 5 are switched from the state shown in the figure, and at the same time, the contents of the controller 3 at this time are held in the hold circuit ₄ during this switching.
is controlled by this held information, and the contents of setter 1 and detector S ₁ are changed to transmitter T ₁ and
Input to control device C via _T2 . Control device C
compares the two, and then obtains command information for controlling the gain, bias, and/or response speed of the controller 3 to change it from its original state by knowing the ambient air temperature using the detector 6 and taking this into consideration. is output, the function of the controller 3 is changed, and the temperature inside the show case F ₁ is automatically controlled to the value set by the setting device 1.

Thus, periodically the function of each controller 3 is
It is changed appropriately according to a command from the control device C.

The command information of this control device C is stored internally each time. Due to a failure in control device C, each open show case F ₁ , F ₂ and
After the control of F ₃ is left to the terminal devices TE ₁ , TE ₂ and TE ₃ with the variable functions of the controller 3 restored to their original state, when the function of the control device C is restored, the variable function of the controller 3 is again controlled. This is to enable control. However, the command information may not be stored in the control device C, and after the function of the control device C is restored, the variable functions of the controller 3 may be controlled again from the original state.

Furthermore, the switching means 2 and 5 of the above-mentioned embodiments are not necessarily necessary, and similar functions can be provided to the transmitters T ₁ ,
T ₂ or the control device C may be used.

Furthermore, the number of refrigeration apparatuses of this invention is not limited to the above embodiments, and furthermore, within the scope of the technical idea of this invention, replacement of each configuration with equivalents is also possible. It is included.

As described above, this invention has the following unique and remarkable effects.

(b) Each refrigeration device is equipped with a terminal device,
Since the temperature of each refrigeration device can be controlled independently, even if the central control device fails, the temperature control described above can be performed within a certain range.

(b) Since each terminal device is commonly connected to the central control device via a transmitter, even if each refrigeration device is considerably distributed, the total wiring length for transmitting control signals will not be that long. , reduction of construction costs,
Noise countermeasures can be easily taken.

(c) Since the central control device periodically checks the output values of the temperature setter and temperature detector corresponding to each refrigeration device and corrects the variable function of the variable controller, it is possible to prevent external disturbances from occurring using normal means. Therefore, even if the temperature of the refrigeration system is not accurately controlled, accurate temperature control can be expected by modifying the target value of the controller or changing the gain. If ambient air temperature information is also input to the central control device, the temperature control will be more accurate. Furthermore, the delay in transmission time due to the presence of a transmitter in the central control device is not a substantial drawback since the change in disturbance is usually on the order of time.

(d) If a switching means is provided to read the outputs of the temperature setter and temperature detector of the central control device, and a hold circuit is provided to hold the contents of the controller when the switching means is switched, the central control device The above-mentioned reading does not significantly affect the control of the refrigeration system.

(e) If a refrigerant throttle valve is used as the refrigeration capacity control device, the configuration will be simple and control will be easy.

(f) Not only can the overall configuration be simplified, but
It can be easily implemented using conventional refrigeration equipment.

[Brief explanation of the drawing]

1 and 2 are block diagrams showing a conventional centralized temperature control device for a refrigeration system, and FIG. 3 is a block diagram showing an embodiment of the present invention. F ₁ , F ₂ and F ₃ ... Refrigeration open case (refrigeration equipment), S ₁ , S ₂ and S ₃ ... Temperature detector, V ₁ , V ₂ and V ₃ ... Refrigerant throttle valve (refrigeration capacity control device), VC ₁ , VC ₂ and VC ₃ ... valve control device, TE ₁ , TE ₂ and TE ₃ ... terminal device, C...
Central control device, T ₁ and T ₂ ... Transmitter, 1 ...
Temperature setter, 2 and 5...Switching means, 3...Variable controller, 4...Hold circuit, 6...Ambient air temperature detector.

Claims (1)

[Scope of Claims] 1. A plurality of refrigeration devices each including at least a temperature detector and a refrigeration capacity control device, a terminal device connected to each of these refrigeration devices, and a common connection to these terminal devices via a transmitter. the terminal device includes a temperature setting device, and a variable controller configured to input the outputs of the temperature detector and the temperature setting device and output a command to the refrigeration capacity control device; The central control device periodically reads the output of a temperature detector and a temperature setter corresponding to one of the refrigeration devices,
A centralized temperature control device for the refrigeration system, which outputs a command for controlling the variable function of the variable controller based on the value. 2. The centralized temperature control device for a refrigeration system according to claim 1, wherein the centralized control device also inputs the output of an ambient air temperature detector and outputs the command. 3. The centralized temperature control device for a refrigeration system according to claim 1, wherein the variable functions of the variable controller are at least a variable gain function and a variable bias function. 4. The terminal device is provided with a switching means for switching at least the outputs of the temperature detector and the temperature setting device to be input to the central control device, and is further provided with a hold circuit that holds the output contents of the variable controller at the time of switching. A centralized temperature control device for a refrigeration system according to claim 1. 5. The centralized temperature control device for a refrigeration system according to claim 1, wherein the refrigeration capacity control device is a refrigerant throttle valve.