JPS60256768A - Method and device for controlling refrigeration system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus and method for controlling a refrigeration system. More particularly, the present invention relates to expansion valves, such as solenoid operated valves, and the operation of solenoid valves. 1□ゎIv%h
K, woo, 5--6. --; - A system that responds to parameters of a refrigeration system to adjust the temperature of the refrigeration system. Still more particularly, the present invention provides a solenoid valve that is periodically energized and deenergized during each cycle of valve operation and a solenoid valve that is periodically energized and deenergized during each cycle of valve operation to regulate the flow of refrigerant through the valve. and a control system responsive to a refrigeration system parameter (e.g., overheating) that changes the ratio of solenoid valve energization and deactivation times during that time.

Typically, a refrigeration system includes a compressor, a condenser coil, and an evaporator coil. The refrigerant vapor is compressed to high pressure by a compressor and directed to a condenser where the high pressure refrigerant vapor is condensed to a high pressure liquid. An expansion valve is positioned between the condenser and evaporator so that the liquid refrigerant from the condenser can be expanded adiabatically before entering the evaporator.

In the evaporator, the low-pressure refrigerant absorbs heat from the surroundings and is at least partially converted to vapor, which is returned to the compressor inlet via the suction pipe. In many conventional refrigeration systems, the expansion valve is a so-called thermostatic expansion valve. Typically, a thermostatic expansion valve has an expansion port within it, and the valve member of the cold W legal viscosity X t-* passes through the four ports. A spring biases the valve member toward its closed position. A diaphragm actuator is provided. One side of the diaphragm is exposed to the suction gas pressure, and the other side is connected via a capillary tube to a thermostatic valve in heat transfer relationship with the refrigerant vapor (called suction gas) exiting the evaporator. has been done.

The valve is filled with a suitable volatile fluid (eg, a refrigerant), thereby exerting a pressure force on the valve member via a spring and direfram actuator that counteracts the force of the suction gas pressure. When the thermostatic valve detects an increase in mII of the suction gas with respect to its pressure, the net pressure force exerted on the diaphragm actuator is correspondingly increased, thereby causing it to open further and Allowing refrigerant to flow through the evaporator, thereby reducing the suction gas temperature. When a drop in suction gas temperature is detected, the thermostatic
The valve reduces the pressure force exerted on the diaphragm actuator, thereby allowing the spring to at least partially close the valve, thus reducing refrigerant flow to the evaporator and increasing the suction gas thirst. let

Generally, thermostic expansion valves are adjusted or set to maintain the suction gas at a predetermined supermaturity level or setting. Superheat is a term generally defined as the temperature of the refrigerant vapor above the evaporation temperature of the refrigerant at a specified pressure of the refrigerant. In many refrigeration systems, thermostic expansion valves are preset at the factory to maintain a predetermined level of superheat and control the flow of refrigerant through the evaporator in response to changes in the refrigeration system's operating conditions. It is impossible or impractical to change the superheat setting of a typical thermostatic expansion valve during operation of the refrigeration system to thereby maximize the operating efficiency of the refrigeration system.

In an effort to overcome the shortcomings of known thermostic expansion valves in that the superheat setting could not be changed during operation of the refrigeration system in response to changing operating conditions (e.g. changes in refrigeration heat load or outside air temperature). A so-called electrically actuated modulating expansion valve was developed in 1995. Such an electrically actuating modulating expansion valve is disclosed in U.S. Pat. In this electrically actuated expansion valve, a plurality of bimetallic elements and a heater element are inserted, and when the heater element is energized, the bimetallic element expands in the axial direction, opening the valve between (
. When the heater element is deenergized, the bimetal element cools and contracts axially, closing the valve. This electric heater/bimetal actuator is often called a heat motor. By controlling the temperature generated by the heater element in the motor, this electrically actuated expansion valve regulates the flow of refrigerant through the valve.
It can be adjusted in response to system parameters (eg, overheating).

These known electrically actuated expansion valves meet their intended purpose: 1. : It worked well for its purpose, but I, j was 1.4. It has the disadvantage that it requires □ka□1i(7)e -h, E-9, Aua, -・□eta. Accordingly, it has been desirable to develop a low cost electrically actuated expansion valve that can be operated to adjust the flow of refrigerant in response to the needs of the refrigeration system.

Among the many objects and features of the present invention may be noted: providing an apparatus and method for controlling a refrigeration system expansion valve in response to the parameters of the refrigeration system; turning the valve on and off; - The cycle is integrated to determine the constant yet variable g of refrigerant flow through the refrigeration system! 1! To provide the above apparatus and method using a low cost, directly actuated solenoid valve that is repetitively or periodically energized and deenergized in response to refrigeration system parameters to enable modulated proportional control. Providing the above apparatus and method using an expansion valve opened and closed by non-modulated electrical actuation to function as an internally cooled flow control valve, a proportional flow control system for a refrigeration system as described above. As a solenoid valve for use in low +1-F+ kneading m-heu! / 0
To provide a ar&M AHm a JJ ml\%Jlenoid valve as a method of controlling the flow of refrigerant through an evaporator, even when the difference between the monitored parameter and the predetermined parameter is small. To provide a control method using both proportional control and integrator control systems such that the control of The object of the present invention is to provide a solenoid valve as described above without adverse effects; and to provide a solenoid valve as described above and a control system that can be used in a wide range of capacity refrigeration systems.

Specifically, the apparatus of the present invention controls a refrigeration system. The refrigeration system includes a compressor having an inlet and an outlet;
It includes a condenser connected to the outlet of the compressor and an evaporator connected to the condenser and the inlet of the compressor. An expansion valve is located between the condenser and the evaporator. The condenser supplies high pressure liquid refrigerant to the evaporator. As the refrigerant flows through the expansion valve, it expands and is converted to vapor in the evaporator as the refrigerant absorbs heat from its surroundings. The control device of the present invention includes a solenoid valve that constitutes the above-mentioned expansion valve. The solenoid valve includes a valve body having a flow path therein for passing a flow of refrigerant. A valve seat forming part of the flow path is provided within the valve body. Blocking the flow of refrigerant through the flow path.

A valve member is provided that is selectively movable between a closed position in close contact with the valve seat and a closed position away from the valve seat to permit flow of refrigerant through the flow path. A solenoid actuator is provided which is energized to move the valve member from its closed position to its closed position. The valve further includes a spring for resiliently biasing the valve member from its closed position to its closed position. Furthermore, the control device of the present invention includes:
Periodically or repeatedly energizing and deenergizing the solenoid actuator with a ratio of energizing (open) time to deenergizing (closed) time for each cycle responsive to one or more operating parameters of the refrigeration system. , thereby including control means for regulating the flow of refrigerant through the refrigeration system.

The method of the present invention for controlling an expansion valve for a refrigeration system employs the apparatus generally described above. The method includes monitoring a parameter of the refrigeration system and generating a signal in response to the parameter. This signal then causes repeated periodic activation of the solenoid valve at a ratio of the activation time to deactivation time of the solenoid valve during each period responsive to the signal to regulate the flow of refrigerant through the refrigeration system. Used to activate and deactivate.

Other objects and features of the invention will be partly obvious and partly pointed out in the following description.

Referring now to the drawings, and in particular to FIG. 1, a refrigeration system is schematically shown generally designated by the reference numeral 1.

The refrigeration system is shown to be a heat pump system and includes a hermetic compressor 3 having an inlet 5 and a refrigeration lower. The lower part of the compressor is connected to an ordinary four-way reversible valve 9. One outlet of the reversible valve 9 is connected to a coil 11 located outside the building in which the pump system 1 is located. outdoor coil 11
The exit is ya. an expansion valve 15 connected to the inlet of another coil 13 placed within the coil 8 and for regulating the flow of refrigerant (from the outdoor coil to the indoor coil or vice versa);
is arranged between coils 11 and 13. The indoor coil output [1 is reversible, connected to the other side of the valve 9,
The central suction port of the reversible valve is also connected to the compressor port 5 by a suction pipe 17. In operation, by reversing the position of the reversible valve 9, the heat pump system can operate in a cooling mode or a heating mode. In cooling mode, the heat pump operates as an air conditioning system with the outdoor coil 11 acting as a condenser and the indoor coil 13 acting as an evaporator. In heating mode, the flow of refrigerant through both coils is reversed so that the indoor coil acts as a condenser and the outdoor coil acts as an evaporator. Throughout the remainder of this specification, for the purpose of ease of understanding and explanation, the heat pump system 1 will be described in such a way that the outdoor coil 11 acts as a condenser and the indoor coil 13 acts as an evaporator. It is assumed that it is operating in cooling mode.

Next, with reference to FIG. 2, the expansion valve 15 will be explained in detail. Preferably, expansion valve 15 is a valve using a low cost, direct actuating solenoid actuator. It is understood that when solenoid valve 15 is energized, solenoid valve 15 is fully open, and when solenoid valve 15 is deenergized, all flow of refrigerant through the valve is blocked. It will be. The valve 15 has an inlet 21 and an outlet 2
The valve body 19 includes a valve body 19 having a flow path F having a flow path F therein. As usual, the large diameter tube ends at the tips are sealably attached (welded) to the valve body 19 so as to define an inlet 21 and an outlet 23, respectively. These large diameter tube ends at their tips make it possible to easily integrate the valve into the refrigerant tubes of the refrigeration system 1, for example by welding the tube ends in place. Expansion valve port 25
is provided in the channel F intermediate the inlet and outlet ends of the channel, and this expansion boat 25 is oriented generally upwardly (as shown in Figure 2). Annular shoulder or valve F
j! ! It is composed of 27. Two vertical channels extend concentrically into the valve seat 27, allowing refrigerant to flow from channel F in one direction to the valve seat. A diagonal flow path 31 is provided downstream from the expansion boat 25 to allow refrigerant to flow from the expansion boat to the outlet L123.

As indicated generally by reference numeral 33,
A solenoid actuator is provided for valve 15. This solenoid actuator as a whole “
C includes a valve member designated by reference numeral 35;
This valve member permits the flow of refrigerant through the flow path F from the open position (shown in FIG. 2) to the open position (the position shown in FIG. Valve seat 27
The open position (as shown) is raised axially away from the
1).It is movable in the axial direction between the The valve member is axially movable through a stroke S, as shown in FIG. 2, as it moves between its closed and open positions. Preferably, this stroke is limited to a short distance, such as 0.020 inches (0.5 mm), thereby limiting the velocity of the valve member during actuation and limiting the impact forces during valve opening and closing.

An elastic seal 39 is provided at the lower end of the valve member 35, which comes into close contact with the valve seat 27 to seal the flow path E when the valve member 35 is in its closed position.

Of course, when the valve member 35 is in its open position, the seal 3
9 is away from the valve seat and allows the flow of refrigerant through the flow path F.

According to the present invention, since the side surface bearing area of the valve seat 27 is relatively large, when the elastic seal 39 is in close contact with the valve seat,
It will be appreciated that substantial concaveness of the resilient valve member is prevented, yet the valve member is easily sealed onto the valve seat. In addition, when the elastic valve member moves to its closed position and comes into close contact with the valve seat, the valve member ″)W″ impact load 1<t? ′・ ,1
1. Furthermore, the solenoid actuator 33 includes a tube 41 with an axial force direction of 9, inside which a solenoid core 4 is inserted.
3 are fixedly held and arranged.

Preferably, the core is made of a suitable ferromagnetic material. The lower end of the tube 41 flares outwardly, as indicated by the reference numeral 44, and this lower end extends over the valve body 19.
The tube is sealably attached (eg, welded) to the valve body, thereby sealing the tube to the valve body and preventing leakage of refrigerant.

A compression spring 47 in the form of a conical coil is interposed between the movable valve member 35 and the core 43, and connects the valve member 35 to the core/core 43.
1.3 and towards an open position in which it contacts the valve seat 27. As shown, the spring 47 is disposed in a blind hole 49 in the upper end of the valve member, and the upper end of the spring is received in a corresponding blind hole 51 in the bottom surface of the core 43. There is. The diameter of the hole 49 of the valve member 35 and the hole 51 of the core 43 is the same as that of the spring 47.
It will be appreciated that the holes are slightly larger than the maximum diameter so that the springs can be compressed without coming into contact with the walls of these holes. Preferably, the compression coil spring 47 is a conical coil spring having a minimum diameter at its top in contact with the core 43, forming a spring whose spring constant increases with increasing deformation of the spring.

Thus, when the valve member 35 is fully retracted into the solenoid bore, the spring is most compressed and exerts the greatest bias on the valve member. Solenoid coil 53 connects to tube 41
is surrounding. This solenoid coil is surrounded by a metal plate cover 55. It will be appreciated that suitable electrical wires (not shown) for the coils extend from the housing 55, thereby allowing selective energization and de-energization of the coils.

Referring now to FIG. 7, another embodiment of the solenoid actuated expansion device or valve of the present invention is illustrated generally with reference numeral @1.
5'. As can be seen by comparing valves 15 and 15' shown in FIGS. 2 and 7, respectively, this second' embodiment of the solenoid valve differs in many respects from valve 15 previously described. Structural and operational
Very similar or identical. It will be appreciated that portions of valve 15' that correspond structurally and operatively to portions of valve 15 have been designated with reference numerals appended to the reference numerals in FIG.

The main difference between valve 15 and valve 15' is the arrangement of the inlet 21' and the passage 29' leading to the expansion valve boat 25'. Second
In the illustrated valve 15, the flow passage 29 extends substantially perpendicular to the inlet flow passage F and communicates with the bottom surface of a resilient seal 39 carried by the valve member 35. Thus, valve 1
The force due to the pressure of the refrigerant entering the flow path through 5 acts directly on the bottom surface of the valve member and acts against the biasing force of spring 47 which keeps the valve in the closed position. Further, due to the energization of the solenoid coil 3, the valve member 35 moves away from the valve seat 27 in the axial direction II! 1, thereby causing the refrigerant to flow through the flow path 29.
The water is allowed to flow from there to the diagonal flow path 31 and from there to the outlet 23. Since the distance that the valve member moves axially in response to energization of the solenoid directly determines the cross-sectional area of the valve opening, the flow rate of refrigerant through the valve also depends on the length of the stroke of the valve member.

As can be seen from FIG. 7, the inlet flow path 21' extending from the inlet 21' is an oblique flow path. It communicates with a chitonbage C surrounding the lower end of the valve member 35'. It will be appreciated that the refrigerant flows freely between the sleeve 41' and the valve member 35', so that the refrigerant fills the space S. Thus, the refrigerant pressure within chamber C does not counteract the closing force of spring/17', thus ensuring that valve member 35' is maintained in the closed position.

Furthermore, the outlet passage 25' is substantially concentric with the valve seat 27';
It further has a narrow orifice O therein which constitutes an expansion orifice for metering the flow of refrigerant into the outlet passage of the valve. Due to the energization of the solenoid 53' of the valve 15' and the movement of the valve member 35' axially away from the valve seat 27', the cross-sectional area of the valve opening between the bottom surface of the resilient seal 39' and the valve seat 27' increases. It will be understood that the wI cross-sectional area of the orifice O instantly becomes much larger than that of the orifice O. Thus, the valve ``'035''K % (7) m jn @ 13'
6 J ill ~ 1-. 5.1 "The refrigerant flowing through the valve 15' reaches the maximum flow condition or the throttled flow condition through the metering orifice O regardless of the stroke 891 of the valve 35'. Therefore, this It will be appreciated that the provision of the orifice substantially reduces the sensitivity of the refrigerant flow rate through the valve 15' to the length of the valve stroke S''. Additionally, a shading band 8B is provided to improve the magnetic attraction and quietness of operation of the valve member 351 when the solenoid coil 53' is energized with AC power from the control system 57.

In accordance with the present invention, an on/off solenoid expansion valve 15 or 15 is provided for regulating the flow of refrigerant through the refrigeration system 1, as indicated generally by the reference numeral 57.
Means is provided responsive to one or more refrigeration system parameters to control operation of the refrigeration system. More particularly, the control means 57 periodically (repetitively) energizes the valve 15 at a ratio of the energization (1Ffl) time of the valve to the de-energization (closing) time of the valve in response to the refrigeration parameter being monitored. ), thereby regulating the flow of refrigerant through the refrigeration system to maintain the temperature of the refrigerant exiting the evaporator 13 (or flowing through the suction pipe 15) within a predetermined superheat range. Contains a power source for power generation.

The control unit operates to continuously compare monitored refrigeration system parameters to known values.

Upon detection of an error between the monitored parameter and a reference or known value, the output voltage signal supplied to the solenoid valve 15 is changed accordingly, thereby causing the system 11"
and the monitored parameters.

Although many system parameters can be monitored, such as the temperature of the outside air or the temperature of the lubricant in the reservoir of the compressor 3, a preferred system parameter is the superheat temperature of the suction gas discharged from the evaporator into the suction pipe 17. .

FIG. 3 shows a block diagram of a preferred control system 57 of the present invention, illustrating its functional principles.

FIG. 6 shows a detailed circuit diagram of this control system. The values of the components of the circuit of FIG. 6 are shown in the table below.

Resistor component number Resistance (Ω) R1, R254, 02K R3' 4.22K R42,, 21K R5, R198, 25K R6, R181, 96K R71, 62K R9330K R10100K R1143 R12164, 8K R22, R23G, 19K R15, R44, R4G 2,49K R161,5K R1710K R2624,9K p R27, R2949,9K R281G, 4 K R30, R31, R32, R421K R33, R3411K R38, R393, 16K R41280K R'13 123 K R13' 2.2K R146 ,02K [35. R3710K R3G 3.3K R47100K R48100 R491,5K R2, R8, R21 (trillpOj) 500R
20, R24, R4 (+(trimpot) I K
R45 (trilpOj) 500 1<56 430 R51560 Capacitor component number Capacitance (flF), H61,
. 2 330'' 03, C40,01 C70,33 CG, C80,1 510 Diode component number Model % Formula % Component number Model Q1. Q2. Q3. Q5. Q6 NPN 2N3904
Operational amplifier component number Type % formula % Other components Component number Explanation Model % formula % From the above description and the block diagrams and detailed circuit diagrams of FIGS. 3 and 6, those skilled in the art can understand that the control means 57 Since the structure and operation of the system can be understood, its explanation is unnecessary and will therefore be omitted.

As before, valve 15 or valve 15' is periodically energized and deenergized. As used herein, the term "held constant" means that the control means 57 is continuously (at least while the compression 1113 is operating) but constantly, as shown in FIG. means operating in a series of consecutive periods P of time. Each period P is the normal time response of the evaporator (
or time constant). For example, suppose the parameter being controlled is superheating. When the valve listens, the superheat begins to drop. A typical evaporator time response is such that if the valve remains fully open, about 20 seconds are required for a substantial reduction in superheat to occur. Since the valve is typically open for less than 4 seconds, superheat control is relatively transparent. Due to the heat capacity and other characteristics of the evaporator, the evaporator does not respond quickly enough to the controlled parameter to follow each pulse of the valve.

The control means 57 automatically outputs an alternating current during each cycle of monitoring in response to the refrigeration system parameters being monitored and an error signal generated by comparing the desired system parameters to the selected reference. and each period P
and a trigger circuit for selectively terminating the current output at some point in time.

In particular, the control means 57 changes the ratio of the energizing time of the solenoid valve 15 to the respective deenergizing time during each period P in response to the error signal. If the error signal is zero (or other preselected value), the voltage output signal supplied to the solenoid valve will be terminated at time zero during each station ill P, and the solenoid valve will not be energized at all. be understood. Thus, valve 15 remains closed, blocking the flow of all refrigerant through the refrigeration system. If the error signal is at or exceeds another preselected value, the voltage output signal remains on for the entire period P.

The solenoid valve thus remains open continuously, allowing maximum flow of refrigerant through the refrigeration system 1. As mentioned above, the solenoid performs discrete A/OFF operation by proportionally changing the ratio of the energization time and the de-energization time during each period P between the upper and lower limits of the error signal. 1
It will be appreciated that 5 functions as a continuously variable modulated refrigerant control valve.

The superheat of the refrigerant in the suction pipe 17 is used as a system parameter and the superheat is set to a predetermined level (e.g. 8
In applications where it is desired to maintain the refrigerant at a lower temperature, the desired superheat of the refrigerant can be maintained by having a ratio of on time or energization time for the solenoid operated valve equal to about 0.7. is shown. FIG. 5 shows that the ratio of the on (or energized) time of the valve 15 to the total cycle is also about 0.7. If, for example, the period jIP is about 4, then the ., っv FI'*151C□6o, っ
;・:1 is energized) time is approximately 2.8 seconds, and off (
The deenergization time is approximately 1.2 seconds.

If the overheat detected by the control means 57 is above a preselected value (for example 8°) of overheat, the control means 57 will increase the on-time of the valve. If, on the other hand, the detected overheating is too low, the control means reduce the on-time accordingly, thereby bringing the overheating to the desired preselected level.

As mentioned above, the period P is relatively short compared to the time constant or time response of the frozen system 1. Thus, 1iIN11
1 system 57 actually turns the solenoid valve 15 on.
Integrate the off step to approximately steady state operating conditions. For example, if the on-time to period ratio is equal to 0.5, this means that the valve is throttled to an intermediate position between its closed and fully open positions, producing approximately 1/2 the flow rate at its fully open condition. This corresponds to allowing the refrigerant to flow at a flow rate of . Of course, if the ratio of on-time to period P is zero, then the valve is closed and all refrigerant flow through it is blocked, and if the above ratio is 1, the valve is closed. It remains in the closed position for the entire cycle, and the refrigerant flows through the valve at maximum flow rate.
8.

The circuit of the control means 57 is shown in FIG.

The circuit shown in FIG. 6 is on/off according to the present invention @
It will be appreciated that the present invention constitutes a single control circuit for operating the solenoid valve 15, and that any number of suitable control circuits may be used. The control system described above changes the ratio of the valve's A2 time to the total period P in proportion to the monitored refrigeration system parameter (eg, temperature difference between evaporator temperature and rise). In some cases, a sample-and-hold or integral-action control device is used as the second type of control device. In this second type of control device, a sampling of the control parameters is carried out, and a finite step change in the ratio of the on time to the period P is determined by an approximation of the controlled parameter and a step change in the time/period ratio. This is done based on a predetermined program relationship between the two. In other words, the direction of the step change in the time/period ratio (ie, positive or negative) is a function of the value of the controlled parameter.

Referring now to Figure 8, a further control stage is shown generally designated by the reference numeral 57'.

In this control means, a proportional output signal of the type )-F generated by the control means 57 is combined with a so-called integral system. Thus, control system 51' may be referred to as a proportional and integral type control system. Integral type control systems are often referred to as automatic control systems. Although a proportional control system such as that shown in FIG. 6 is relatively simple to design and manufacture, such a proportional control system is
It is not well suited when the error signal generated by the method must be reduced to zero or near zero. This is because the controlled element (e.g. the expansion device 15) is activated only in response to the error signal.

In proportional control systems, some degree of error from the set point is usually required to control the operation of the device. Of course, the error can be minimized by increasing the gain of the control system, but on the other hand, the control system usually becomes unstable and is prone to erroneous operation.

An integral control system, on the other hand, operates to adjust the controlled element as long as there is an error (ie, deviation from a set point) in the controlled parameter, such as superheat. For example, in the refrigeration system described herein, the superheat (i.e., the difference between the refrigerant temperature T at the expansion coil outlet and the refrigerant temperature T at the expansion coil outlet) is normal at equal time intervals. It is measured as follows. If the detected error signal is positive (i.e., if the temperature difference exceeds the set point, indicating that the refrigerant supply is inadequate), then the period of the expansion valve 15 is - (e.g. 1% of the total period P
) is increased by After the next time interval, the control parameters are sampled again, and if the error is still positive, the valve period is increased by an additional 1%. , conversely, if bL is negative; if a difference signal is detected, the period length due to valve 15 remains in the listening position is reduced by a predetermined value (for example, 1%), and this process is , continues as long as a negative error signal remains. However, integral control systems often lack the ability to quickly respond to sudden transient phenomena. The control system of the present invention, as shown in detail, is a combination of proportional and integral control methods.In this way, the ability of the proportional control system to quickly respond to sudden transients and the controlled parameters (
This is combined with the ability of the integral control system lx to reduce the error (overheating) to zero. In the control system 57', the opening degree of the valve 15 or 151 (the length of the A-on time of the beating circumference w3[)) is the sum of the proportional signal and the integral signal.

Referring to FIG. 8, the input end of the control system 57' consists of two temperature sensors T and T which detect the temperature of the refrigerant at the inlet and outlet of the evaporator E, respectively. A third parameter called the set point, e.g. Ts is the ideal or desired value of the refrigerant temperature at the evaporator outlet that is lower than the cold ts temperature at the evaporator inlet (i.e. T4
Ti>.

The control system 57' is further referred to as an integrator count 1
, which is numerically equal to the value of the opening degree of the valve 15 or 15' (i.e. the ratio of the opening time to the total time of the period P) expressed as a percentage. control system 5
At the first electrical activation of 7', the integrator count l is at a certain value, thereby ensuring that the valve 151 is initially asking at least some small opening. The first 20% of the ratio between the open time and the total time of period P is the integrator count.■
typical for 4 below bfi h < the third parameter Ts (i.e. the heating set point).

The integrator count rV) value is changed by the controller 57' according to the following relationship: In the first case, if −
r! If P--rα is less than the value 4 below the set point Ts, the control system L1 subtracts an increment (1%) from each time interval T1-1 divider count value l. In the second case, if 14-T(L is selected and the IC set point Ts
(For example, if it is larger than 4゛[), the control system 57
′ adds a certain inflation factor [· (for example, 1%) to the integrator count value ■ at each interval rliit. For refrigerant supply control applications, the value of hourly interval 1 is typically about 1 minute.

The contribution of the proportional control to the valve opening (i.e. the ratio of the duration or energization time of the valve 15 to the total time of the period P) is ((T each - T^) -T
s ) equal to xG, where G is the control system 57'
is the gain of the proportional amplifier part of ). When the temperature in the above equation is expressed in degrees Fahrenheit and the valve opening is expressed as a percentage of the total equivalent capacity, the value of gain G is approximately 3 for optimal control of the refrigeration system. . system 57'
The ratio of the opening or energizing time to the total length of the period P and the valve position expressed as a percentage is given by the equation below. :Opening time%-I + (
IT-? −~Tα)Ts)XG.

For example, referring to FIG. 9, when the system is operating such that the actual superheat is below about 4, (TeP-Ti)-
It can be seen that -rs=o. Thus, the signal supplied by the proportional part of the system is O, but the percentage of the ratio of the opening time of the valve 15 to the period P is approximately 1
It remains at 7%. This represents the integral part of the control system and maintains the 4° filtration membrane setting.

In fact, as long as the superheat remains below about 4, the integrator is not operational and the value of ■ remains constant at 17%.

However, if T8 becomes -6 times louder than O, the integral part of the control system will change the valve opening time and the cycle l! l
It begins to add an increment to the ratio to lP and the proportional control becomes active, thereby increasing refrigerant flow through the evaporator and decreasing superheat. thus,
The control system has the stability of an integral controller + the responsiveness of a proportional controller.

The circuitry of the control system 57' is shown in detail in FIG. 8, and the components of the sled are shown in the table below.
Those skilled in the art will be able to construct and use control system 57'.

6.1 Resistor component number Resistor R1' 4.02 K R3' 4.22 K R5'14'R60'R67' 1,5KR
6'R58' 1,96 K R7" (i, 19 K R9'R10'R23'10.01<1 and 11'
1. (32K R12' 8.25 l( R13' 1.58 K R16'R70' 348.OK R17' 43 R18'R19'R20'R47'R52' R
G2' 100.0K R21' 9. IK R22' 3.33 K R24'R72' 6.48 K R25' 1.5K.

R26' 620 R27'R31'R71'R73'R74' 4
．． 99 K R29'l'E$3' 9.09 KR30' 1.
7/3 K R32'F 33' 1, I K R34'f 49'R50' R! i3'R5,5"
R57'R63' 2.05 36 in KR35'l
'21!1K R37'R38' 4,42 K R39'R43' 8.87 K R41'R42' IK R44'R45' 2,49 K R46'R51" 619K [18" 11 (+, OK R54-20, 0K R5G' 1. (12K R61' 576 R64'RG!i' 2.05K R68' 3.48 K R69' 649.0 to R4'R8'R15' (T riuot> 500 R28' (T riIllpot) 5KRGo'
(Trimpot) IK Ki17 Pacita 17tI4 component search number Capacitance (μF) CIC2' 330 C3' 100 C41G5'0.22 CG'07"016' 0.1 8110 09IO168 CIO'C11'CI2'C14'ICI3'
3.3 C15' O,,047 Season C17' 1 "11 Purchase" [U 1' U 2' (] 3' u c I CCA 324 Quad, Arithmetic Instrument U 5' ICC△358 Dual Arithmetic Amplifier () G' ICCD4060 CMO8 counter U 7' U 8' ICI) 0451G binary U /
D Counter U 9' DCDACO8 D/A j110' ICCD4050 CM OS Hex, j 7 < buffer l'Ull' NE 5554 F 15V DC1 node Q 1' Q 2' Q 3' 2N390G PNP transistor Q 4 '2N6028 PLIT Prog .

Unijunction transistor Q 5' Q 6' 2N3904 NPNt-transistor D 1' D 2' D 3' D 5'' D 6'
D 7'N4001 Rectifier diode D 4' LJM 336 2,5V base W-LD 1'
R[ED, L ED The structure has been explained in detail so far, lζ valve 15 or 15
' is particularly suited for use as an on/off continuously variable flow control valve utilized in accordance with the control system and method of the present invention because it has a long service life even when repeatedly opened and closed in the manner previously described. well suited. Opening and closing of the movable valve member 35! Because of the special features of the valve that make it small, and because of the relatively large contact area of the resilient valve member 39 on the valve seat 27, the valve has a long service life and requires little or no maintenance.

The method of the present invention for controlling an expansion valve for a refrigeration system employs an on/off operating solenoid valve 15 as previously described and a control system 57 as previously described. In summary, Kinoe's method involves the process of monitoring parameters of the refrigeration system, such as the superheating of the suction gas returned to the input of the compressor 3 or the temperature difference between the inlet and outlet of the evaporator coil. Contains. This temperature difference is often considered to be an acceptable approximation of true superheating on a refrigeration coil, especially with low pressure drop. The control system is then used to generate a signal in response to the refrigeration system parameters, and the signal is used to regulate the flow of refrigerant through the refrigeration system (f
It is used to periodically energize and deenergize the solenoid operated valve at the ratio of the energization time of each energization cycle in response to the i signal to the period length.

Alternatively, the method of controlling a solenoid valve 15 or 15' for on/off operation using a control system 57' includes:
It includes utilizing an integral portion of the control system to maintain the superheat of the refrigerant below a predetermined set point S, e.g. In response to an increase in the load on the evaporator, refrigerant superheating (T
(--TL) increases, thus increasing (T each -T(L>-
Make Ts larger than O. Thereby the control system 5
7' proportional part is added to the integral part of the control system,
This increases the ratio of A-hour/period lIP and also increases the refrigerant flow. If the actual overripeness (No. 1-T, L) becomes less than zero, the Ril ill system 57
The proportional part of 1 remains passive, but an increment is removed from the integrator count *r, thus reducing the ratio of the on-time to the period value 1], and thus reducing the refrigerant flow.

It will be appreciated that in some applications it may be advantageous to have a valve that is open when the solenoid is deenergized and closed when the solenoid is energized.

From the foregoing description, it will be appreciated that other objects of the invention are achieved and other advantageous results obtained.

Since various modifications may be made to the structure or method described above within the scope of the present invention, all matters described or illustrated above are illustrative and are not intended to limit the scope of the present invention. do not have.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a refrigeration system, more particularly a heat pump refrigeration system, employing the on/off operating solenoid valve of the present invention, controlled in accordance with the apparatus and method of the present invention. FIG. 2 is an enlarged cross-sectional view of the solenoid control valve of the present invention. Figure 3 is a block diagram of a control system for controlling the operation of the solenoid valve shown in Figure 2. ;・i□
It is a graph showing the relationship between the ratio of the darkening time to the deadening time and the overheating and cooling of the refrigerant. FIG. 5 shows the time course of the coil current energizing the solenoid actuator of the solenoid valve. FIG. 6 is an electrical circuit diagram of the control system of the present invention. FIG. 7 is an enlarged cross-sectional view of another embodiment of the solenoid control valve of the present invention. FIG. 8 is an electrical circuit diagram of the proportional and integral control system of the present invention. FIG. 9 shows the ratio of opening time to period P as a function of the monitored parameter, e.g. superheat, of a solenoid valve controlled by a proportional and integral control system as shown in FIG. It is a graph. DESCRIPTION OF SYMBOLS 1... Refrigeration system, 3... Compressor, 5... Compressor population, 7... Compressor outlet, 9... Reversible valve, 11...
...Outdoor coil, 13...Indoor coil, 15...Expansion valve, 17...Suction pipe, 19...Valve body, 21...
- Channel inlet, 23... Channel outlet, 25... Expansion valve boat, 27... Valve seat, 29... Heavy flow channel, 31...
・Diagonal flow path, 33... Solenoid actuator, 35... Valve member, 3... Elastic seal, /11.
... Pipe, 43 ... Solenoid core, 47 ... Spring, 49.51 ... Mortar hole, 53 ... Solenoid coil, 55 ... Cover, 57 ... Control means, ".・・・
Flow path, 0...A refurbishment Applicant Emerging Electric Company Agent Patent attorney Masaki Akashi 44i<Tb-rc)-,,, Shin (Method) (Spontaneous) Procedural amendment 1982 18/20 1, Incident Indication 1982 Patent Application No. 110647 2
, Name of the invention Relationship between refrigeration system control method and apparatus 3 and correcting sound 1 Patent applicant address St. Louis, Missouri, United States of America
West Florilin T-8100 Name ■Margin Electric Company 4,
Agent Address Address: 1-5-19-6, Shinkawa 1-chome, Chuo 1g, Tokyo 104, Subject of amendment Drawings

Claims (5)

[Claims] (1) a compressor having an outlet and an outlet; a condenser connected to the outlet of the compressor; an evaporator connected to the condenser and the inlet of the compressor; an expansion valve disposed between the evaporator and the evaporator, the apparatus for controlling a refrigeration system in which the condenser supplies high-pressure liquid refrigerant to the expansion valve; Including the tre°noid valve. The solenoid valve includes a valve body having a flow path therein for allowing a flow of refrigerant to pass therethrough, a valve seat forming a part of the flow path, and a valve seat configured to prevent the flow of refrigerant through the flow path. a valve member selectively movable between a closed position in intimate contact with the valve seat and a closed position away from the valve seat to permit flow of refrigerant through the flow path; and a valve member downstream from the valve seat. is located within said flow path of said valve means to direct the flow of refrigerant through said flow path to a predetermined flow rate substantially regardless of the distance that said valve member is from its closed position when said valve means is open. a metered orifice for throttling; a solenoid actuator energized and deenergized to move said valve member between its closed positions; and a solenoid actuator energized and deenergized to move said valve member between said closed positions. a spring for elastically biasing the
and control means for periodically energizing and deenergizing the solenoid actuator to thereby regulate the flow of refrigerant through the solenoid valve. Device. (2) a compressor having an inlet and an outlet; a condenser connected to the outlet of the compressor; an evaporator connected to the condenser and the inlet of the compressor; and the condenser and the evaporator. an expansion valve disposed between the refrigeration system, wherein the condenser supplies high pressure liquid refrigerant to the expansion valve, and the refrigerant expands as it flows through the expansion valve.
The expansion valve includes a valve body having a flow path therein for allowing a flow of refrigerant to pass through, a valve seat forming a part of the flow path, and the valve seat for blocking the flow of refrigerant through the flow path. a valve member selectively movable between an open position in intimate contact with the valve seat and an open position spaced from the valve seat to permit flow of refrigerant through the flow path; located within the flow path to throttle the flow of refrigerant through the flow path to a predetermined flow rate substantially regardless of the distance the valve member is from its open position when the valve member is open; a solenoid energized and deenergized to move the valve member between its closed position and its open position;
an actuator; a spring for resiliently biasing the valve member toward its open position; and a biasing time and period length responsive to one or more operating parameters of the refrigeration system. control means for periodically energizing and deenergizing said solenoid actuator at a ratio of 1 to 1 to thereby regulate the flow of refrigerant through said expansion valve.
A refrigeration system characterized by a solenoid operated valve. (3) a compressor having an inlet and an outlet, a condenser connected to the outlet of the compressor, an evaporator connected to the condenser and the inlet of the compressor, and the condenser and the evaporator connected to each other; an expansion valve disposed between the refrigeration system and the refrigeration system, wherein the condenser supplies high pressure liquid refrigerant to the expansion valve, and the refrigerant expands as it flows through the expansion valve;
The expansion valve includes a valve body having a flow path therein for allowing a flow of refrigerant to pass through, a valve seat forming a part of the flow path, and the valve seat for blocking the flow of refrigerant through the flow path. a valve member selectively movable between a closed position in intimate contact with the flow path and an open position spaced from the valve seat to permit flow of refrigerant through the flow path; a solenoid actuator energized and deenergized to move the valve member between its open positions;
a spring for elastically biasing the opening time and said valve in one or more of said refrigeration systems;
□ - The ratio of the length of the period responding to the data shown in 5.
1 Periodically energize and deenergize the noid actuator i′
and control means for thereby regulating the flow of refrigerant through the expansion valve, the control means having means for detecting overheating of the refrigerant discharged from the evaporator; Means for generating a set point signal 1S representing the desired operating conditions of the refrigeration system and generating an integrator h runt signal corresponding to a predetermined ratio of the valve opening time and the period length greater than zero; and wherein the integrator count signal generating means has means for comparing the overmaturity to the set point signal;
If the difference between the superheat and the set point is less than zero, an increment is axed from the predetermined ratio of the energization time and the period length, and if the difference between the superheat and the set point is 2. A refrigeration system according to claim 1, wherein if the difference between is greater than zero, an increment is added to the predetermined ratio of the energization time and the period length. (4) In an expansion device for a refrigeration system having a compressor having an inlet and an outlet, a condenser connected to the outlet of the compressor, and an evaporator, a solenoid-operated valve; means for controlling operation and thereby regulating the flow of refrigerant through the evaporator, the solenoid valve having a flow path for passing refrigerant and a means for controlling the flow of refrigerant through the evaporator; a valve member movable between an open position in which refrigerant can flow and an open position in which refrigerant flow is prevented; and a solenoid for moving the valve member between the open position and the closed position. and wherein the control means periodically energizes and deenergizes the solenoid in a ratio of the open time of the valve to the length of the period in response to one or more parameters of the refrigeration system. means for regulating the flow of refrigerant to the evaporator, and for the control means to detect overheating of the refrigerant discharged from the evaporator;
means responsive to the superheat for generating a signal proportional to the superheat of the refrigerant discharged from the evaporator; and means for comparing the proportional signal to a predetermined value and thereby altering the ratio of the open time and the period. means for generating a set point signal; and means for generating an integrator count corresponding to a predetermined fraction of said ratio greater than zero; the signal generating means includes means for comparing the overheating with the set point signal;
If the difference between the superheat and the set point is less than zero, an increment is subtracted from the ratio, and if the difference between the superheat and the set point is greater than zero,
An expansion device for a refrigeration system, characterized in that an increment is added to said ratio. (5) a compressor having an inlet and an outlet; a condenser connected to the outlet of the compressor; an evaporator connected to the condenser and the inlet of the compressor; and the condenser and the evaporator. an expansion valve disposed between the condenser and the expansion valve, the condenser supplying high pressure liquid refrigerant to the expansion valve, and the expansion valve being selectively operable between an open device and a closed position. a solenoid valve that is repeatedly energized and deenergized such that the valve repeatedly energizes and deenergizes in a ratio between the energization time and the period length that is variable to regulate the flow of refrigerant through the valve; A method of controlling an expansion valve of a refrigeration system angle comprising: monitoring a parameter of the refrigeration system; generating a signal in response to the parameter; and generating a set point signal. emitting an integrator count signal corresponding to a predetermined ratio of the valve opening time and the period length; and comparing the parameter with the setpoint signal, If the difference between the set points is less than zero, then the inflation factor I is subtracted from the predetermined ratio 7fi I, and if the difference between the parameter signal and the set point is greater than zero, then the inflation clement to the predetermined ratio.