KR100795568B1 - Apparatus for exchaging heat using electronic expansion valve, external unit using electronic expansion valve and system for multi air-conditioner - Google Patents

Abstract

An apparatus for exchanging heat by using an electronic expansion valve, an outdoor unit of an air conditioner by using an electronic expansion valve, and a multi air conditioner system are provided to improve overcooling degree performance to prevent generation of flash gas at an inlet of an expansion valve to prevent deterioration of performance and reliability of a multi air conditioner system, and lower a temperature of a sucked refrigerant when an air conditioner is operated under an overload conditioner to lower a temperature of cooled and discharged refrigerant gas of a compressor. A condenser(510) condenses an introduced refrigerant to spray a high-temperature refrigerant. An evaporator(520) evaporates an introduced refrigerant to spray a low-temperature refrigerant. An accumulator(530) built in a heat exchanger exchanges heat between the high-temperature refrigerant and the low-temperature refrigerant. A compressor(540) compresses gaseous refrigerant sprayed from the accumulator built in a heat exchanger to spray a high-temperature and high-pressure refrigerant to the condenser. An expansion valve(550) expands the liquid refrigerant of the accumulator built in a heat exchanger to spray the expanded refrigerant to the evaporator. An overcooling degree control unit(564) measures a temperature and a pressure of an inlet of the expansion valve, operates an overcooling degree in accordance with a difference between a saturated temperature of the measured pressure and the measured temperature, and bypasses the liquid refrigerant of the accumulator built in a heat exchanger to the outlet of the evaporator.

Description

Heat exchanger using electronic expansion valve, air conditioner outdoor unit and multi air conditioning system using electronic expansion valve {Apparatus for exchaging heat using electronic expansion valve, External unit using electronic expansion valve and System for multi air-conditioner}

1 shows an example of installation of a multi-air conditioner.

2 is a structural diagram of a conventional heat exchanger built-in accumulator.

3 is a block diagram of a system including the heat exchanger built-in accumulator of FIG.

FIG. 4 illustrates the effect of the heat exchanger built-in accumulator of FIG. 2 in the refrigeration cycle.

5 is a block diagram of a heat exchange apparatus using an electromagnetic expansion valve according to the present invention.

FIG. 6 illustrates the effect of the refrigeration system to which the heat exchanger of FIG. 5 is applied.

7 is a graph showing an example of the relationship between the subcooled measurement value and the opening degree of the electromagnetic expansion valve.

8 illustrates an example of an operation algorithm of the subcooling controller 560 according to the compressor operation signal.

The present invention relates to a heat exchanger, and more particularly, to a heat exchanger using an electromagnetic expansion valve, an air conditioner outdoor unit and a multi air conditioning system using an electromagnetic expansion valve.

An air conditioner is widely used as an air conditioner used to cool a room by a heat of vaporization of a refrigerant using a cooling cycle.

Multi-air conditioners are installed in a single outdoor unit in a number of indoor units, by increasing the compactness and high efficiency of the product, the current increase in the center of large-scale buildings, and is replacing the conventional centralized air conditioning system.

However, since the installation distance of the outdoor unit and the indoor unit is increased by the installation of the multi-air conditioner, the length of the extension pipe is greatly increased. In addition, the height difference between the units is greatly increased because the floor height gap between the indoor unit and the outdoor unit increases. Increasing the length of the extension pipe and the height difference greatly increases the pressure drop in the extension pipe, especially the liquid pipe, thereby reducing the supercooling at the inlet of the expansion valve mounted in the indoor unit, and generating the flash gas to generate the expansion valve. The refrigerant flow rate is greatly reduced.

1 shows an example of installation of a multi-air conditioner.

In a conventional outdoor unit, by applying an accumulator or a double tube heat exchanger having a built-in heat exchanger, the supercooling degree is increased by heat-exchanging the high temperature refrigerant at the outlet of the condenser and the low temperature refrigerant at the outlet of the evaporator.

2 is a structural diagram of a conventional heat exchanger built-in accumulator.

The accumulator built-in heat exchanger has a structure in which an internal heat exchanger in the form of a coil is mounted inside an accumulator used in the related art. In Fig. 2, ① denotes the inlet of the accumulator, ② denotes the outlet of the accumulator, ③ denotes the inlet of the internal heat exchanger, and ④ denotes the outlet of the exhaust heat exchanger.

3 is a block diagram of a system including the heat exchanger built-in accumulator of FIG.

FIG. 4 illustrates the effect of the heat exchanger built-in accumulator of FIG. 2 in the refrigeration cycle.

The high temperature liquid refrigerant at the outlet of the condenser flows through the internal heat exchanger, and the low temperature refrigerant at the outlet of the evaporator flows into the accumulator so that the liquid refrigerant accumulates at the bottom of the accumulator, and only the refrigerant in the gas phase is sucked into the compressor. The heat exchange between the high temperature refrigerant and the low temperature refrigerant increases the degree of supercooling at the inlet of the expansion valve and increases the degree of superheat at the inlet of the compressor.

The heat transfer and supercooling performance of the built-in heat exchanger is determined by the temperature difference between the refrigerant temperature at the internal heat exchanger inlet and the refrigerant temperature at the accumulator inlet. In other words, the lower the temperature of the accumulator inlet, the higher the heat transfer performance, so that the supercooling degree is greatly increased. When the air conditioner is operated under an overload condition, since the accumulator inlet temperature corresponding to the evaporator outlet temperature is high, heat transfer in the accumulator with heat exchanger is hardly generated, and thus an increase in the supercooling rate is hardly expected. In addition, when the pressure drop in the pipe is severe due to an increase in the length of the extension pipe due to an installation problem, the accumulator built in the heat exchanger alone may not sufficiently maintain the supercooling degree at the inlet of the expansion valve located in the indoor unit. In addition, since the amount of increase in subcooling is not controlled by an external signal, but the amount of increase in subcooling is determined according to the operating conditions, optimal control of the system is impossible.

Therefore, in the conventional accumulator with a heat exchanger, the amount of increase in the supercooling in the interior is determined by the operating conditions of the refrigeration cycle, so that active control of the supercooling is not performed, and the refrigerant gas temperature at the outlet of the evaporator is high at the overload condition. Therefore, the increase in the supercooling degree in the accumulator with heat exchanger is very small, and the inlet superheat of the compressor with the supercooling is also increased in the accumulator with heat exchanger, so that the density of the compressor suction refrigerant decreases, thereby reducing the volumetric efficiency in the compressor. There is a problem of degrading the performance.

Therefore, the first technical problem to be achieved by the present invention is to prevent the reduction in performance and reliability of the system in advance, to maintain the air conditioning system in the optimum operating conditions, and to reduce the temperature of the cooling and discharge refrigerant gas of the compressor It is to provide a heat exchange device using an electromagnetic expansion valve.

The second technical problem to be achieved by the present invention is to provide an air conditioner outdoor unit using an electronic expansion valve to which the heat exchanger using the above-mentioned electromagnetic expansion valve is applied.

The third technical problem to be achieved by the present invention is to provide a multi-air conditioner system in which the heat exchanger using the above-mentioned electromagnetic expansion valve is applied to an outdoor unit and an indoor unit.

In order to achieve the first technical problem, the present invention provides a condenser for condensing an incoming refrigerant to inject a high temperature refrigerant, an evaporator for evaporating the incoming refrigerant to inject a low temperature refrigerant, and a high temperature refrigerant injected from an outlet of the condenser. A heat exchanger built-in accumulator for heat-exchanging the low temperature refrigerant injected from the outlet of the evaporator, a compressor for compressing the refrigerant in the gas phase injected by the heat exchanger built-in accumulator and injecting a high-temperature high-pressure refrigerant to the condenser, the liquid phase of the accumulator built-in heat exchanger The temperature and pressure of the expansion valve and the inlet of the expansion valve for inflating the refrigerant to the evaporator is measured, and the degree of supercooling is calculated according to the temperature difference between the measured saturation temperature of the pressure and the measured temperature, Of the accumulator with built-in heat exchanger according to the degree of subcooling It provides a heat exchange apparatus using an electronic expansion valve comprising a supercooling control unit for bypassing the refrigerant in the phase to the outlet of the evaporator.

In order to achieve the second technical problem, the present invention is an air conditioner outdoor unit connected to an evaporator for evaporating a refrigerant flowing from the air conditioner indoor unit to inject a low-temperature refrigerant, the condenser for condensing the incoming refrigerant to inject a high-temperature refrigerant A heat exchanger built-in accumulator having a coil type internal heat exchanger for exchanging the high temperature refrigerant injected from the outlet of the condenser and the low temperature refrigerant injected from the outlet of the evaporator, and compressing the refrigerant in the gas phase injected from the built-in heat exchanger. Measuring the temperature and pressure of the expansion valve and the inlet of the expansion valve and the expansion valve for injecting the evaporator by expanding the liquid refrigerant of the accumulator built-in heat exchanger and the injection to the condenser, the saturation temperature of the measured pressure and the measurement Cooling depending on the temperature difference Operation, and provides the according to the calculated supercooling degree with the electronic expansion valve including a supercooling degree control unit for bypassing the refrigerant of the heat exchanger internal to the accumulator liquid outlet of the evaporator air conditioning outdoor unit.

In order to achieve the third technical problem, the present invention provides a multi-air conditioner system including a plurality of indoor units and at least one outdoor unit, wherein the indoor units each include an evaporator which injects low-temperature refrigerant by evaporating the refrigerant introduced therein. The outdoor unit includes a condenser for condensing refrigerant introduced from the plurality of indoor units and injecting a high temperature refrigerant, and a coil heat exchanger, and a high temperature refrigerant injected from the outlet of the condenser and a low temperature injected from the outlet of the evaporator. A heat exchanger built-in accumulator for exchanging a refrigerant, a compressor for compressing a refrigerant in a gaseous phase injected by the heat exchanger built-in accumulator and injecting the refrigerant into the condenser, an expansion valve for expanding a liquid refrigerant in the heat exchanger built-in accumulator and injecting the evaporator into the evaporator; Inlet of the expansion valve Measures the temperature and pressure, calculates the supercooling degree according to the measured temperature difference between the saturation temperature of the pressure and the measured temperature, and the liquid refrigerant of the built-in heat exchanger accumulator according to the calculated subcooling the outlet of the evaporator Provided is a multi-air conditioner system including a subcooling control unit to bypass the furnace.

The present invention relates to an apparatus and a control unit for increasing and controlling the supercooling degree in a condition where the subcooling degree is not sufficiently generated, such as an overload condition.

The present invention improves the supercooling performance of a conventional built-in heat exchanger accumulator and at the same time reduces the compressor inlet refrigerant temperature, thereby preventing the compressor volume efficiency from being reduced, and also reducing the compressor discharge temperature. The purpose is to ensure operational reliability. In addition, an object of the present invention is to provide a control algorithm and a control algorithm for improving the control performance of the present system.

The system includes a device for detecting the supercooling degree at the inlet of the expansion valve, a device for increasing the supercooling at the inlet of the expansion valve mounted in the indoor unit of the multi-air conditioner, and a control unit and algorithm thereof. .

The operation of the heat exchanger applied to the air conditioner is as follows.

The refrigerant gas compressed at a high temperature and high pressure in a compressor is exchanged with ambient air in a condenser to be a high temperature liquid refrigerant, and impurities are filtered in a receiver drier. It is then converted to a low temperature liquid refrigerant through an expansion valve and then vaporized by heat exchange with ambient air in an evaporator. At this time, the air cooled by the heat of vaporization is absorbed by a fan to cool the room. The refrigerant gas vaporized as described above is filtered after the liquid refrigerant is filtered in the accumulator.

Hereinafter, with reference to the drawings will be described a preferred embodiment of the present invention. However, embodiments of the present invention illustrated below may be modified in many different forms, and the scope of the present invention is not limited to the embodiments described below.

5 is a block diagram of a heat exchange apparatus using an electromagnetic expansion valve according to the present invention.

The heat exchange apparatus of FIG. 5 includes a refrigerant liquid injector. In addition, the heat exchange device of Figure 5 is a refrigerant liquid injector is a built-in heat exchanger accumulator 530 for heat exchange between the high temperature refrigerant liquid and the low temperature refrigerant gas, an electronic expansion valve for bypassing a part of the liquid refrigerant at the outlet of the internal heat exchanger ( 566, a subcooling degree sensing module 563 for sensing a refrigerant state at the inlet of the expansion valve 550, a subcooling control unit 564 for implementing a control algorithm, and a driving driver 565.

A part of the high temperature refrigerant liquid at the outlet of the internal heat exchanger is expanded by using the electromagnetic expansion valve 566 and converted into a low temperature refrigerant gas, and then introduced into the accumulator 530 inlet, thereby greatly generating a temperature difference with the internal heat exchanger. This improves heat transfer performance and supercooling. At this time, the opening degree of the internal orifice of the electromagnetic expansion valve 566 is controlled according to the refrigerant state at the inlet of the expansion valve 550 provided in the indoor unit.

The condenser 510 condenses the introduced refrigerant and injects a high temperature refrigerant. Preferably, the outdoor unit may include a condenser 510 and a compressor 540.

The evaporator 520 injects the refrigerant of low temperature by evaporating the refrigerant introduced therein. Preferably, the indoor unit may include an evaporator 520.

The heat exchanger built-in accumulator 530 has an internal heat exchanger in the form of a coil. In addition, the built-in heat exchanger accumulator 530 heat exchanges the high temperature refrigerant injected from the outlet of the condenser 510 and the low temperature refrigerant injected from the outlet of the evaporator 520.

The compressor 540 injects the high temperature and high pressure refrigerant compressed by the refrigerant in the gas phase injected from the accumulator 530 in the heat exchanger to the condenser 510.

The expansion valve 550 expands the refrigerant in the liquid phase of the heat exchanger built-in accumulator 530 and injects the evaporator 520.

The subcooling control unit 560 measures the temperature and the pressure of the inlet of the expansion valve 550, and calculates the subcooling degree according to the temperature difference between the measured saturation temperature and the measured temperature. In addition, the subcooling control unit 560 bypasses the liquid refrigerant of the heat exchanger built-in accumulator 530 to the outlet of the evaporator 520 according to the calculated subcooling degree.

FIG. 6 illustrates the effect of the refrigeration system to which the heat exchanger of FIG. 5 is applied.

By reducing the temperature degree at the outlet of the accumulator 530 through the injection of the coolant liquid to the inlet of the accumulator 530, the effect of cooling the compressor 540 and reducing the discharge temperature of the compressor 540 can also be obtained. According to the present invention, it can be seen that the amount of enthalpy change due to pressure change is larger than that of the conventional accumulator.

At this time, the opening degree of the internal orifice of the electromagnetic expansion valve is controlled in accordance with the state of the refrigerant at the inlet of the expansion valve installed in the indoor unit.

The subcooling control unit 560 includes a subcooling detection module 563, a subcooling control unit 564, and a driving driver 565. The signals from the pressure sensor 561 and the temperature sensor 562 provided at the inlet of the expansion valve are input to the subcooling degree sensing module 563, and the measured value of the subcooling degree is calculated by an internal calculation algorithm.

In order to calculate the supercooling degree, first, the pressure from the pressure sensor 561 is converted into a saturation temperature, and when the converted saturation temperature is subtracted from the temperature value from the temperature sensor 562, the subcooling degree at the inlet of the expansion valve is calculated. It is calculated.

The calculated subcooling measurement value is transmitted to the subcooling control unit 564.

The subcooling control unit 564 operates the electromagnetic expansion valve 566 by a predetermined control algorithm.

For example, the subcooling control unit 564 outputs a control signal for opening the electromagnetic expansion valve 566 when the calculated subcooling degree is less than the threshold value. In addition, the subcooling control unit 564 outputs a control signal for closing the electromagnetic expansion valve 566 when the calculated subcooling degree is greater than or equal to the threshold value. At this time, the threshold value is a temperature value that can be arbitrarily determined by one of ordinary skill in the art.

For example, the subcooling control unit 564 operates the electromagnetic expansion valve 566 when the subcooling degree is less than " 2.5 ° C. "

7 is a graph showing an example of the relationship between the subcooled measurement value and the opening degree of the electromagnetic expansion valve.

In FIG. 7, it is understood that when the measured subcooling degree is 2.5 ° C. or higher, the opening degree of the expansion valve is kept fully closed, but when the measured subcooling degree is lower than 2.5 ° C., an algorithm for gradually increasing the opening degree of the expansion valve is applied. Can be.

The subcooling control unit 564 converts the operation opening of the electromagnetic expansion valve 566 into a 5 volt level pulse signal according to the output signal of the control algorithm and transmits it to the driving driver 565.

The drive driver 565 converts the control signal of the subcooling control unit 564 into a voltage signal for driving the electromagnetic expansion valve. For example, the driving driver 565 converts a 5 volt level pulse signal into a 12 volt level driving signal, which is a driving voltage of the electromagnetic expansion valve 566, and transmits it to the electromagnetic expansion valve 566.

At this time, the electromagnetic expansion valve 566 is opened in accordance with the operating signal in the full-close state (open state). Signals from the pressure sensor 561 and the temperature sensor 562 at the inlet of the expansion valve 550 are continuously input to the supercooling degree sensing module 563 to determine whether the operation is performed.

For example, when the subcooling value is higher than " 2.5 ° C. ", the operation stop signal is transmitted to the subcooling control unit 564, and the electromagnetic expansion valve 566 can be designed to return to the full-close state. Can be.

8 illustrates an example of an operation algorithm of the subcooling controller 560 according to the compressor operation signal.

In this case, whether the subcooling control unit 560 is operated may also be controlled by a compressor operation signal. When the operation signal is input from the compressor 540 to the subcooling control unit 564, the subcooling control unit 560 is operated. On the other hand, when the stop signal comes from the compressor 540, the subcooling control unit 560 does not operate. That is, the subcooling control unit 560 does not operate when the compressor 540 is not operated.

The invention can be implemented via software. When implemented in software, the constituent means of the present invention are code segments that perform the necessary work. The program or code segments may be stored on a processor readable medium or transmitted by a computer data signal coupled with a carrier on a transmission medium or network.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary and will be understood by those of ordinary skill in the art that various modifications and variations can be made therefrom. However, such modifications should be considered to be within the technical protection scope of the present invention. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, according to the present invention, it is possible to prevent the reduction of the performance of the system and the reduction of the reliability by preventing the generation of flash gas at the inlet of the expansion valve mounted in the indoor unit by improving the supercooling performance in the multi-air conditioner. In addition, the air conditioner system can be maintained at an optimum operating condition, and when the air conditioner is operated under an overload condition, the compressor suction refrigerant temperature is reduced, thereby reducing the temperature of the compressor cooling and discharge refrigerant gas.

Claims (12)

A condenser for condensing the incoming refrigerant and injecting a high temperature refrigerant; An evaporator for evaporating an incoming refrigerant to inject a low temperature refrigerant; A heat exchanger built-in accumulator for heat-exchanging the high temperature refrigerant injected from the outlet of the condenser and the low temperature refrigerant injected from the outlet of the evaporator; A compressor for compressing a refrigerant in a gaseous phase injected from the accumulator with a heat exchanger and injecting a high temperature and high pressure refrigerant into the condenser; An expansion valve for expanding a liquid refrigerant of the accumulator built-in heat exchanger and injecting the refrigerant into the evaporator; And The temperature and pressure of the inlet of the expansion valve is measured, and the degree of supercooling is calculated according to the temperature difference between the measured saturation temperature of the pressure and the measured temperature, and according to the calculated degree of subcooling, Heat exchanger using an electronic expansion valve comprising a subcooling control unit for bypassing the refrigerant to the outlet of the evaporator. The method of claim 1, The subcooling control unit An electronic expansion valve for bypassing the liquid refrigerant at the outlet of the accumulator with the heat exchanger to the outlet of the evaporator; A temperature sensor for measuring a temperature of an inlet of the expansion valve; A pressure sensor for measuring the pressure at the inlet of the expansion valve; A subcooling degree sensing module configured to calculate a subcooling degree according to the measured temperature difference between the saturation temperature of the pressure and the measured temperature; A subcooling control unit for outputting a control signal for opening the electromagnetic expansion valve when the calculated subcooling degree is less than a threshold value; And And a driving driver for converting the control signal into a driving voltage of the electromagnetic expansion valve to drive the electromagnetic expansion valve. The method of claim 2, The supercooling detection module And converting the measured pressure into a saturation temperature and calculating the subcooling degree by subtracting the measured temperature from the saturation temperature. The method of claim 2, The subcooling control unit And outputting a control signal for closing the electromagnetic expansion valve when the subcooling degree is equal to or greater than the threshold value. The method of claim 2, The subcooling control unit And a control signal for opening the electromagnetic expansion valve to an opening degree inversely proportional to the subcooling degree, when the subcooling degree is less than the threshold value. The method of claim 1, The subcooling control unit Heat exchanger using an electromagnetic expansion valve, characterized in that only operating when the compressor is operating. The method of claim 2, The subcooling control unit Heat exchanger using an electromagnetic expansion valve, characterized in that only operating when the compressor is operating. The method of claim 2, The control signal is a pulse signal of 5 volts level, the drive voltage is a heat exchange device using an electronic expansion valve, characterized in that the operation signal of 12 volts level of the electromagnetic expansion valve. In the air conditioner outdoor unit connected to the evaporator for evaporating the refrigerant flowing from the air conditioner indoor unit to inject a low temperature refrigerant, A condenser for condensing the incoming refrigerant and injecting a high temperature refrigerant; A heat exchanger built-in accumulator having an internal heat exchanger having a coil shape to heat exchange the high temperature refrigerant injected from the outlet of the condenser and the low temperature refrigerant injected from the outlet of the evaporator; A compressor for compressing a refrigerant in a gaseous phase injected from the accumulator built in the heat exchanger and injecting the refrigerant into the condenser; An expansion valve for expanding a liquid refrigerant of the accumulator built-in heat exchanger and injecting the refrigerant into the evaporator; And The temperature and pressure of the inlet of the expansion valve is measured, and the degree of supercooling is calculated according to the temperature difference between the measured saturation temperature of the pressure and the measured temperature, and according to the calculated degree of subcooling, An air conditioner outdoor unit using an electronic expansion valve including a subcooling control unit for bypassing a refrigerant to an outlet of the evaporator. The method of claim 9, The subcooling control unit An electronic expansion valve for bypassing the liquid refrigerant at the outlet of the accumulator with the heat exchanger to the outlet of the evaporator; A temperature sensor for measuring a temperature of an inlet of the expansion valve; A pressure sensor for measuring the pressure at the inlet of the expansion valve; A subcooling degree sensing module configured to calculate a subcooling degree according to the measured temperature difference between the saturation temperature of the pressure and the measured temperature; A subcooling control unit for outputting a control signal for opening the electromagnetic expansion valve when the calculated subcooling degree is less than a threshold value; And And a driving driver for converting the control signal into a driving voltage of the electromagnetic expansion valve to drive the electromagnetic expansion valve. In the multi air conditioning system comprising a plurality of indoor units and at least one outdoor unit, The indoor unit And an evaporator which injects refrigerant of low temperature by evaporating the refrigerant introduced therein, The outdoor unit A condenser that condenses the refrigerant flowing from the plurality of indoor units and injects a high temperature refrigerant; An accumulator with a heat exchanger having a coil-type heat exchanger configured to exchange heat between the high temperature refrigerant injected from the outlet of the condenser and the low temperature refrigerant injected from the outlet of the evaporator; A compressor for compressing a refrigerant in a gaseous phase injected from the accumulator built in the heat exchanger and injecting the refrigerant into the condenser; An expansion valve for expanding a liquid refrigerant of the accumulator built-in heat exchanger and injecting the refrigerant into the evaporator; And The temperature and pressure of the inlet of the expansion valve is measured, and the degree of supercooling is calculated according to the temperature difference between the measured saturation temperature of the pressure and the measured temperature, and according to the calculated degree of subcooling, And a supercooling control unit for bypassing a refrigerant to an outlet of the evaporator. The method of claim 11, The subcooling control unit An electronic expansion valve for bypassing the liquid refrigerant at the outlet of the accumulator with the heat exchanger to the outlet of the evaporator; A temperature sensor for measuring a temperature of an inlet of the expansion valve; A pressure sensor for measuring the pressure at the inlet of the expansion valve; A subcooling degree sensing module configured to calculate a subcooling degree according to the measured temperature difference between the saturation temperature of the pressure and the measured temperature; A subcooling control unit for outputting a control signal for opening the electromagnetic expansion valve when the calculated subcooling degree is less than a threshold value; And And a drive driver converting the control signal into a driving voltage of the electromagnetic expansion valve to drive the electromagnetic expansion valve.

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