KR20100068143A - Refrigerant compressor and freezing cycle device - Google Patents

Abstract

PURPOSE: A refrigerant compressor and a refrigeration cycle device are provided to improve durability by controlling the increasing of the acid value of refrigerating machine oil. CONSTITUTION: A refrigerant compressor comprises: a motor(3) which includes a rotor(10) and a stator(11) in a sealed container which stores refrigerating machine oil(14); a rotary shaft which is installed to the rotor; and a compression part(2) which is connected to the motor through the rotary shaft. The refrigerant which is sealed in the refrigerant compressor is R410A, R407C or R404A. The refrigerating machine oil uses polyol ester oil as base oil and contains alkyl glycidyl ether compound as an acid acceptor.

Description

REFRIGERANT COMPRESSOR AND FREEZING CYCLE DEVICE}

The present invention ensures reliability in the case of using a hydrolyzable lubricating oil, such as an ester-based refrigerator oil, in a domestic heat pump type refrigeration cycle using an HFC refrigerant.

Conventionally, the refrigerant | coolant of home room air conditioner used HC22 type R22. However, from the point of view of global environmental protection, it has shifted to an HFC system that does not contain chlorine in its molecules. The substitutes include R410A and R407C alone or in combination of two or more of R32, 125 and 134a. However, since HFC refrigerants have different polarization states between the HCFC refrigerants and molecules, the compatibility with conventional mineral oils is poor, and the oil returnability in the cycle is lowered. Therefore, as a refrigerator oil having the required solubility, a method of securing oil return without changing the basic configuration of the refrigeration cycle using synthetic oil such as ester oil is taken.

However, this refrigeration oil is hydrolyzable, and if there is moisture in the cycle, it causes a hydrolysis reaction and decomposes into raw fatty acids and alcohols. This raw fatty acid raises the total value of the refrigeration oil, resulting in corrosion wear of the sliding parts. In addition, when the raw material fatty acid reacts with the metal to form a fatty acid metal salt, it adheres to the cycle and causes a cycle blockage.

As a countermeasure, Patent Document 1 discloses a method of adding a cycloglycidyl ether compound as an acid trapping agent in refrigerator oil. In addition, Patent Document 2 discloses a method of adding a carbodiimide compound. Also, Patent Document 3 discloses a method of using an epoxy compound, glycidyl ester, glycidyl ether, or the like as an additive for trapping water or acid in oil of a refrigerant oil for a hydrocarbon (HC) refrigerant.

[Patent Document 1] Japanese Patent Application Laid-open No. Hei 8-231972

[Patent Document 2] Japanese Patent Application Laid-open No. Hei 8-120288

[Patent Document 3] Japanese Patent Application Laid-Open No. 2005-283106

While the patent document 1 has high stability, the reactivity with an acid is slow compared to the production rate of the raw material fatty acid by a hydrolysis reaction, etc., and it cannot immediately capture a fatty acid.

Patent Document 2 has a high reactivity with acid and water, but is immediately consumed, and thus has a great effect on trapping of initial water, but cannot cope with generation of a large amount of acid due to pyrolysis of refrigeration oil.

Patent Document 3 discloses the use of an epoxy compound or the like as an acid trapping agent, but does not specify a specific substance. In addition, hydrocarbons are designated as refrigerants.

When ester oil is used as the refrigeration oil, the acid generated by the hydrolysis reaction or the like may cause corrosion wear of the sliding parts, and the metal soap produced by reaction with the metal may cause a malfunction of the electric valve or the like.

Therefore, an object of the present invention is to suppress the acid value increase of the refrigerant oil in the refrigerant compressor and the refrigeration cycle apparatus using the same, as compared with the conventional refrigerant compressor, and to improve durability.

The object of the present invention,

A motor having a rotor and a stator in an airtight container for storing refrigeration oil,

A rotating shaft fitted to the rotor,

In the refrigerant compressor for receiving the compression unit connected to the motor through the rotor,

The refrigerant enclosed in this refrigerant compressor is R410A, R407C or R404A,

It is achieved by using polyol ester oil as base oil and using refrigeration oil containing an alkylglycidyl ester compound as an acid trapping agent.

Moreover, the said alkylglycidyl ester compound has a structure represented by following formula (1).

(Wherein R is independently and represents an alkyl group having 4 to 12 carbon atoms)

According to the present invention, the durability of the refrigerant compressor and the refrigeration cycle apparatus using the same can be improved.

EMBODIMENT OF THE INVENTION Next, embodiment of this invention is described in detail, referring drawings suitably. The refrigerant compressor and the refrigeration cycle apparatus using the same of the present embodiment are characterized by using hydrofluorocarbon as a refrigerant and a predetermined polyol ester as a refrigerant oil as described later. Here, after explaining the refrigeration cycle apparatus using the refrigerant | coolant compressor which concerns on this embodiment, this refrigerant compressor is demonstrated.

1 is a cross-sectional view of a hermetic refrigerant compressor. The hermetic refrigerant compressor includes a rotary system, a scroll system, a reciprocating system and the like, but will be described using an example of a hermetic refrigerant compressor of a scroll system. Among them, the scroll compressor is a sliding part, and the swing scroll and the fixed scroll come into contact with each other, so that the temperature rise hardly occurs instantaneously, and the scroll compressor rarely rises to a temperature at which the high-performance acid scavenger having high residual ratio reacts sufficiently. In addition, in the case of the rotary compressor, the vane and the roller are in point contact, so that the temperature of the sliding part is likely to increase. In the case of the reciprocating compressor, the cylinder and the piston are brought into surface contact, but since the viscosity of the refrigeration oil is low, the oil film is severely formed and heat generation of the sliding portion is likely to occur.

In this refrigerant compressor, the compressor part 2 and the electric motor 3 are accommodated in the sealed case 1 which also serves as oil storage. The compressor part 2 has the revolving scroll 4, the fixed scroll 5, the frame 6, the crankshaft 7, and the Oldham ring 8 as main components. The suction pipe 9 which communicates with an external cycle is sealingly connected to the case 1 which is a sealed container. The motor consists of a rotor 10 and a stator 11, and a crank shaft 7 made of cast iron is fitted to the rotor 10. The crankshaft 7 has an eccentric part 12, and the shaft hole 13 is formed in hollow at one end side.

Moreover, the outer peripheral part of the frame 6 is being fixed to the airtight container 1, and is provided with the bearing which receives the rotation of the crankshaft 7. As shown in FIG. The rotating scroll 4 is rotatably mounted to the eccentric portion 12 of the crankshaft 7, and is formed in the groove formed in the frame 6 and the groove formed in the base plate on the side of the anti-wrap side of the swing scroll 4. The Oldham ring 8 is arranged to be slidable, and the turning scroll rotates without rotating.

In addition, the refrigerator oil 14 is stored in the bottom part, and this refrigerator oil is supplied to the sliding part. The acid trapping agent 14a is added to the refrigerator oil 14. In addition, there is a slot (not shown) for winding a magnet wire in the stator 11 in the electric motor 3, and the surface thereof is covered with an insulating film, as is well known, and the insulating film in the present embodiment is an ester resin. It is formed.

The basic structure of the refrigeration cycle for refrigerators is shown in FIG. In the refrigerating cycle apparatus consisting of the refrigerant compressor (15), the condenser (16), the expansion mechanism (17), and the evaporator (18), the refrigerant compressor (15) sucks and compresses the refrigerant gas of low temperature and low pressure, and the refrigerant of high temperature and high pressure. The gas is discharged and sent to the condenser 16. The refrigerant gas sent to the condenser 16 is sent to the expansion mechanism 17 as a refrigerant liquid of high temperature and high pressure while releasing its heat into the air. The high temperature and high pressure refrigerant liquid passing through the expansion mechanism 17 becomes wet steam of low temperature and low pressure by the throttling effect and is sent to the evaporator 18. The refrigerant entering the evaporator 18 absorbs heat from the surroundings and evaporates. The low temperature low pressure refrigerant gas leaving the evaporator 18 is sucked into the compressor 15, and the same cycle is repeated hereinafter.

In this refrigeration cycle configuration, a refrigerator or the like requires a low temperature evaporator temperature (-40 ° C. or less). If refrigeration oil having poor compatibility with the refrigerant is used here, the refrigerant oil separated from the refrigerant in the heat exchanger or expansion mechanism accumulates, and oil returnability to the compressor 15 is inferior.

3 shows a basic configuration of a refrigeration cycle for an air conditioner. In the refrigerating device consisting of the refrigerant compressor (15), the condenser (16), the expansion mechanism (17), the evaporator (18), and the four-way valve (19), the refrigerant compressor (15) sucks and compresses the refrigerant gas of low temperature and low pressure. The high temperature and high pressure refrigerant gas is discharged and sent to the four-way valve 19. Refrigerant sent here is sent to a condenser in accordance with the refrigerant | coolant flow path in the four-way valve 19 here. Therefore, the coolant rotates counterclockwise as in FIG. 2.

The refrigerant gas sent to the condenser 16 is sent to the expansion mechanism 17 as a refrigerant liquid of high temperature and high pressure while releasing its heat into the air. The high temperature and high pressure refrigerant liquid passing through the expansion mechanism 17 becomes wet steam of low temperature and low pressure by the throttling effect and is sent to the evaporator 18. The refrigerant entering the evaporator 18 is evaporated by absorbing heat from the surroundings, and the low temperature low pressure refrigerant gas leaving the evaporator 18 is sucked into the compressor 1, and the same cycle is repeated hereinafter.

By switching the four-way valve 19, the coolant flow path is changed, that is, the condenser 16 and the evaporator 18 are reversed because the coolant is rotated clockwise as opposed to the above.

In this refrigeration cycle, a room air conditioner or the like requires an intermediate evaporator temperature (-10 ° C. or less). If refrigeration oil having poor compatibility with the refrigerant is used here, the refrigerant oil separated from the refrigerant in the heat exchanger or expansion mechanism accumulates, and oil returnability to the compressor 15 is inferior.

The refrigerant used at this time is a hydrofluorocarbon system, and since chlorine is not contained in the molecule, the lubricant's own lubricity cannot be expected and the wear resistance of the compressor is lowered. By using the above-mentioned refrigerator oil, the lubricity of the refrigerant | coolant / freezer oil mixed liquid can be ensured. As said polyol ester oil, the hindered type synthesize | combined from polyhydric alcohol and monovalent fatty acid, and excellent in heat stability is preferable.

For example, as a polyhydric alcohol,

Pentaerythritol,

There is dipentaerythritol.

For example, as monovalent fatty acid,

Pentanic Acid,

Hexane Acid,

Heptanoic Acid,

Octanoic Acid,

2-methylbutanoic acid,

2-methylpentanoic acid,

2-methylhexanoic acid,

2-ethylhexanoic acid,

Isooctanoic Acid,

3,5,5-trimethylhexanoic acid, etc. are used alone or as two or more types of mixed fatty acids.

In particular, at least one selected from the group of ester oils of fatty acids represented by formula (2), formula (3) or formula (4) having at least two ester bonds in the molecule is preferable as the base oil in the refrigerator oil.

[In formula (2), R <^1> respectively independently represents a hydrogen atom or a C1-C3 alkyl group, and R <^2> respectively independently represents a C5-C12 alkyl group.]

[In formula (3), R <^1> and R <^2> is synonymous with the above.

[In formula (4), R <_2> is synonymous with the above.]

Although the viscosity (measured by JIS K2283) of the refrigeration oil used for the refrigerating device or the air conditioner of Figs. 2 and 3 varies depending on the type of the compressor, the viscosity at 40 ° C. in the scroll compressor has a range of 40 to 100 mm 2 / s. desirable. If the viscosity is less than 40 mm 2 / s, the viscosity of the refrigeration oil in which the refrigerant is dissolved becomes low, and the oil film inside the compressor is not sufficiently maintained, so that lubricity cannot be maintained. Moreover, the sealing property of a compression part cannot also be maintained. On the other hand, when the viscosity exceeds 100 mm 2 / s, mechanical losses such as viscosity resistance and frictional resistance are increased to lower compressor efficiency.

As for the acid trapping agent having an alkylglycidyl ester compound, when the addition amount is less than 0.1% by mass, a sufficient acid trapping effect cannot be expected. On the contrary, when the amount exceeds 1% by mass, the acid trapping agent may be precipitated without being completely dissolved in the freezer oil. . Therefore, as addition amount, 0.1-1.0 mass% is preferable.

In addition, about the organic insulating material used for a compressor motor, the heat-resistant class of electrical insulation is prescribed | regulated by electrical insulation JEC-6147 (Japanese electrical society electrical standard investigation standard standard). However, in the case of organic insulating materials for refrigeration and air conditioning equipment, since they are used in a special environment called a refrigerant atmosphere, they are resistant to deformation and modification due to pressure in addition to temperature, and also come into contact with a polar compound such as refrigerant or refrigeration oil. Extraction resistance, thermal, chemical and mechanical stability and refrigerant resistance should also be considered. Refrigerant resistance referred to herein means, for example, crazing (fine bellows-shaped cracks generated when the film is stressed and then immersed in the coolant) and blister (the coolant absorbed by the film is caused by an increase in temperature). Bubble of the film); As an insulation material for an air conditioner, it is necessary to use the insulation material of a heat-resistant class (Class B 130 degreeC or more).

The most common insulating material used in compressors is PET (polyethylene terephthalate). As a use, the film material is used for the coil insulation with the iron core of a distribution winding motor, and fibrous PET is used for the bundle material of a coil and the coating material of the lead wire of a motor.

As an insulation film other than this,

PPS (polyphenylene sulfide),

PEN (polyethylene naphthalate),

PEEK (polyether ether ketone),

PI (polyimide),

PA (polyamide) etc. are mentioned.

In addition, the main insulating coating material of the coil,

THEIC modified polyester,

Polyamide,

Polyamideimide,

Polyester imide,

Polyester amideimide etc. are used, The double-coated copper wire which double-coated polyester imide amide-imide is used preferably. In the embodiment of the present invention, there is no particular problem even if an antifoaming agent, a lubricity improver, an antioxidant, a metal deactivator, or the like is added to the refrigerator oil.

As a method of confirming the acid trapping agent performance of the refrigerator oil, thermal stability and hydrolyzability were evaluated in the shield tube test. R410A is used as the refrigerant, and polyol ester oil is used as the refrigerator oil. Specifically, a hindered ester oil of VG68 composed of pentaerythritol as an alcohol and i-C8 acid / i-C9 acid (50/50) as a fatty acid is used.

Next, a shield tube test was conducted as the evaluation of the organic insulating material in the compressor. R410A is used as the refrigerant, polyol ester oil is used as the refrigerator oil, and specifically hindered ester oil of VG68 composed of pentaerythritol as alcohol and i-C8 acid / i-C9 acid (50/50) as fatty acid is used. The insulation film used the PET film of heat resistant grade (B class 130 degreeC), and the double coat | wire of polyesterimide polyamide-imide was used for the enamelled copper wire.

The evaluation item of an insulating material is demonstrated. About an insulation film, the tensile strength retention and elongation retention were measured before and after a test. The retention rate was aimed at 50% or more. In addition, about an enamel copper wire, a change of an external appearance, a pencil hardness, winding characteristics, and dielectric breakdown voltage (JIS C 3003) were measured, and craze and blister were observed in refrigerant resistance. These items were aimed to have no change before and after the test.

<First Embodiment>

Table 1 and FIG. 4 show the results of the shield tube test performed as the hydrolyzability evaluation. Refrigerator oil is a polyol ester oil, and specifically, the hindered ester oil of VG68 which consists of pentaerythritol as an alcohol and i-C8 acid / i-C9 acid (50/50) as a fatty acid was used. As shield tube test conditions, iron, copper, and aluminum having a length of 50 mm were put into a glass tube having an inner diameter of 10 Φ as a catalyst, 5 g of refrigeration oil and 1 g of R410A as a refrigerant were sealed and heated up to 14, 21, 28 days at 150 ° C. Thereafter, the color of the oil, the acid value, the residual ratio of the additive, the appearance of the catalyst, and the like were measured. The moisture in the oil was 1000 ppm. As the kind of the acid trapping agent, in order to match the epoxy equivalent, the alicyclic epoxy compound (0.5 mass%) [Formula (5) is used as the alkylglycidyl ester (0.9 mass%) [formula (1)] and the first comparative example. )] Was added respectively.

(Wherein R is independently and represents an alkyl group having 4 to 12 carbon atoms)

Measurement of the acid value and the additive of the refrigeration oil after the test was in accordance with JIS K2501 "Petroleum products and lubricant-neutralization test method". The color was according to JIS K2580 "Petroleum product color test method". The residual ratio of the additive was performed by a method according to JIS K2501 "Petroleum products and Lubricant-neutralization test method".

As a result of the evaluation, when the water content was 1000 ppm, in the first example, no increase in the acid value was observed even in the 28-day heating. In the first comparative example, the increase in the acid value was increased to 0.05 mgKOH / g in the 28-day heating. Confirmed.

When the residual ratio of the acid trapping agent is measured, in the first comparative example, the acid value is raised to 0.05 mgKOH / g even though 47% of the acid trapping agent remains. From this, it can be seen that the reaction rate of acid capture does not reach the rate of acid production. The generated acid may react with the corrosion of the sliding part or the metal to generate metal soap, causing clogging malfunction in the valve.

Second Embodiment

The conditions were changed and the shield tube test performed as hydrolysis evaluation similarly to Example 1 was implemented. The evaluation results are shown in Table 2 and FIG. 5. Refrigerator oil is a polyol ester oil, and specifically, the hindered ester oil of VG68 which consists of pentaerythritol as an alcohol and i-C8 acid / i-C9 acid (50/50) as a fatty acid was used. As shield tube test conditions, iron, copper, and aluminum having a length of 50 mm were put into a glass tube having an inner diameter of 10 Φ as a catalyst, 5 g of refrigeration oil and 1 g of R410A as a refrigerant were sealed and heated at 150 ° C. for up to 20 or 40 days. The color of the oil, the acid value, the residual ratio of the additive, the appearance of the catalyst, and the like were measured. The moisture in the oil was 2000 ppm.

As a result of evaluation, when the water content was 2000 ppm, the refrigeration oil of Example 2 to which the alkylglycidyl ester was added did not have an increase in acid value at 20 days of heating, but only slightly changed to 0.03 mgKOH / g even at 40 days of heating. However, as for the second comparative example in which the alicyclic epoxy compound was added, the increase in the acid value began to increase to 0.04 mgKOH / g at the time of heating on the 20th and 1.13 mgKOH / g for the 40 day heating. It became.

However, when the residual ratio of the acid trapping agent was measured, the residual ratio of the acid trapping agent was high as 67% in the second comparative example, and it was found that the reaction rate of the acid trapping agent did not reach the production rate of the fatty acid.

Third Embodiment

Table 3 shows the results of the shield tube test performed as the oil / refrigerant evaluation of the insulation film. As refrigeration oil, polyol ester oil of VG68 was used. As a shield tube test condition, the insulating material processed into the dumbbell shape of length 50mm and width 3mm as a construction product was put into the glass tube of internal diameter 10Φ, and it is polyol ester oil as refrigeration oil, specifically, it is an alcohol as pentaerythritol and a fatty acid. VG68 hindered ester oil consisting of i-C8 acid / i-C9 acid (50/50): 5 g, R410A: 0.5 g as a refrigerant, after injection and sealing, heating at 130 ° C for up to 40 days, oil color, acid value , Appearance, strength and the like of the construction product were measured. The moisture in the oil was 50 ppm. As a kind of acid trapping agent, alkylglycidyl ester (0.9 mass%) was added.

The acid value of the refrigeration oil after the test was in accordance with JIS K2501 "Petroleum products and lubricant-neutralization test method". The color was according to JIS K2580 "Petroleum product color test method". In addition, the tensile strength of the insulating material was performed by the method according to JIS C2111 "electric insulating paper test method."

As a result of evaluation, deterioration of refrigeration oil was not confirmed about color, acid value, etc. Also about the insulation film material, it confirmed that there was no abnormality, such as an external appearance, tensile strength, and flexibility.

This test method is an accelerated test and corresponds to 10 years or more in terms of actual operating years. Since this is equivalent to the conventional one, that is, even if the conventional one and the one of the example are replaced, it is considered that there will be no influence.

<Fourth Embodiment>

Table 4 shows the results of the shield tube test conducted as an oil / refrigerant evaluation of the enameled wire. Refrigerator oil is a polyol ester oil, and specifically, the hindered ester oil of VG68 which consists of pentaerythritol as an alcohol and i-C8 acid / i-C9 acid (50/50) as a fatty acid was used. As a shield tube test condition, a glass tube having an inner diameter of 10 φ was inserted into a glass tube having an internal diameter of 10 φ and a 10 cm enameled wire as a construction product. After injecting 5 g of polyol ester oil as a freezer oil and 0.5 g of R410A as a refrigerant, it was sealed and 150 ° C. After heating up to 40 days at, the color of the oil, the acid value, the appearance of the construction product, the film strength and the like were measured. The moisture in the oil was 50 ppm. As a kind of acid trapping agent, alkylglycidyl ester (0.9 mass%) was added.

The acid value of the refrigeration oil after the test was in accordance with JIS K2501 "Petroleum products and lubricant-neutralization test method". The color was according to JIS K2580 "Petroleum product color test method". In addition, evaluation of the enameled wire was performed by the method according to JIS C3003 "enameled wire test method", and JIS C3202 "enameled wire." As a result of the evaluation, deterioration of the refrigeration oil was not confirmed. Moreover, about the enamelled copper wire, even if the pencil hardness was 5H and the winding characteristic wound up by the magnetic diameter, it was favorable without showing a crack etc. in a film. The dielectric breakdown voltage was also almost equal to the initial value, and it was confirmed from the appearance that crazing and blistering did not occur, and the target was satisfied.

This test method is an accelerated test and corresponds to 10 years or more in terms of actual operating years.

Since this is equivalent to the conventional one, that is, even if the conventional one and the one of the example are replaced, it is considered that there will be no influence.

<Fifth Embodiment>

The scroll compressor which enclosed the polyol ester oil which added the alkylglycidyl ester compound as an acid trapping agent was mounted in the room air conditioner, and the 90-day actual machine evaluation test was done. 1600g of R410A as a refrigerant, and polyol ester oil as refrigerant, specifically, 460ml of hindered ester oil of VG68 composed of pentaerythritol as alcohol and i-C8 acid / i-C9 acid (50/50) as fatty acid. It was. 0.9 mass% of alkylglycidyl esters of this invention were added as an acid trapping agent. Analysis of the refrigeration oil after the refrigeration oil test confirmed that there was no increase in acid value and that the additive remained at least 50%. The abnormality was not confirmed about the motor insulation material.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor using a hydrofluorocarbon (HFC) refrigerant, and is also applicable to a refrigerating device and an air conditioning installation equipped with the compressor.

1 is a cross-sectional view illustrating a hermetic refrigerant compressor.

2 is a basic configuration of a refrigeration cycle for a freezer.

3 is a configuration diagram of a refrigeration cycle for a basic air conditioner.

Fig. 4 is a diagram showing the results of a hydrolyzability test when 1000 ppm of water was added.

Fig. 5 shows the hydrolytic test results when 2000 ppm of water is added.

<Explanation of symbols for the main parts of the drawings>

1: case

2: compressor unit

3: electric motor

4: turning scroll

5: fixed scroll

6: frame

7: crankshaft

8: Oldham Ring

9: suction pipe

10: rotor

11: stator

12: eccentric part

13: shaft hole

14: refrigerator oil

14a: acid scavenger

15: compressor

16: condenser

17: expansion mechanism

18: evaporator

19: four way valve

Claims (5)

A motor having a rotor and a stator in an airtight container for storing refrigeration oil, A rotating shaft fitted to the rotor, In the refrigerant compressor for receiving a compression unit connected to the motor through the rotary shaft, The refrigerant enclosed in this refrigerant compressor is R410A, R407C or R404A, A refrigerant compressor using polyol ester oil as a base oil and using a refrigeration oil containing an alkylglycidyl ester compound as an acid trapping agent. A refrigeration cycle apparatus comprising at least a compressor, a condenser, an expansion mechanism, and an evaporator and a refrigerant pipe connecting them, A refrigeration cycle device, wherein the compressor is used as the refrigerant compressor according to claim 1. The refrigeration cycle device according to claim 2, wherein the alkylglycidyl ester compound has a structure represented by the following formula (1). [Formula 1]

(Wherein R is independently and represents an alkyl group having 4 to 12 carbon atoms) The refrigeration cycle apparatus according to claim 2, wherein 0.1 to 1.0 mass% of the alkylglycidyl ester compound is added. The refrigerant compressor according to claim 1, wherein the organic material used in the refrigerant compressor is a material which is not deteriorated physically and chemically.

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