An explosion-proof valve

Abstract

An explosion-proof valve disclosed by the present invention comprises a valve body, an explosion-proof shell and a pilot assembly. A valve cavity is arranged inside the valve body. An air inlet A, a working port A and an exhaust port A which are communicated with the valve cavity are arranged on the valve body. A valve rod is slidably arranged inside the valve cavity. The pilot assembly comprises a pilot seat and a micro solenoid valve. The pilot seat is fixed on the valve body. A piston cavity is arranged inside the pilot seat. A piston is slidably arranged inside the piston cavity. The end of the valve rod passes through the valve body and is abutted and matched with the piston. The explosion-proof shell is hermetically connected to the pilot seat. The micro solenoid valve is accommodated inside the explosion-proof shell. An air inlet B, a working port B and an exhaust port B are arranged on the micro solenoid valve. The air inlet A and the air inlet B are communicated through an air inlet channel. The piston cavity and the working port B are communicated through a pilot channel. The exhaust port A and the exhaust port B are communicated through an exhaust channel. A manual rod for opening and closing the pilot channel is arranged on the pilot seat. The present invention has the advantages of quick installation, low manufacturing cost, high sealing performance and good explosion-proof effect.

Description

Technical Field

[0001] The present invention relates to the technical field of solenoid valves, and particularly to an explosion-proof valve. Background Art

[0002] A solenoid valve is an industrial device controlled by electricity magnetism. It is a basic automation component for controlling fluids, belonging to an actuator, and is not limited to hydraulic and pneumatic applications. It is used in industrial control systems to adjust parameters such as the direction, flow rate, speed, and others of the medium. An explosion-proof valve is one of them, mainly applied to occasions with more dust and explosion hazards such as chemical industry, mines, powder metallurgy, etc.

[0003] Traditional explosion-proof valves mainly include a valve body, a pilot head, and an explosion-proof shell. The pilot head is installed on the valve body, and the gas path switching of the valve body is controlled by the pilot head. The explosion-proof shell covers the outside of the pilot head, isolating the electromagnetic component pilot head from the external environment and playing a sealing role. However, there are the following problems in actual applications: First, the pilot head mainly includes components such as a magnetic isolation tube, a static iron core, a moving iron core, a spring, a coil, etc. When assembling the explosion-proof valve, the pilot head cannot be pre-assembled, but the parts of the pilot head need to be installed into the explosion-proof shell one by one. And because there are many spare parts of the pilot head, the assembly is cumbersome and inconvenient, and the assembly efficiency is low. Second, when the pilot head controls the gas path commutation of the valve body, the pressure value of the control gas is affected not only by the intake pressure but also by the stroke of the moving iron core of the pilot head. The greater the stroke of the moving iron core, the greater the opening of the outlet (or controller port) of the pilot head and the greater the flow rate; conversely, the smaller the stroke of the moving iron core, the smaller the flow rate of the control gas. In order to keep the pressure of the control gas within an appropriate range, during design, it is necessary to accurately calculate and repeatedly test the stroke of the moving iron core of the pilot head, resulting in high processing difficulty and high manufacturing cost. Summary of the Invention

[0004] The purpose of the present invention is to provide an explosion-proof valve aiming at the defects and deficiencies of the prior art, which has the advantages of convenient processing, fast installation, low manufacturing cost, high sealing performance, and good explosion-proof effect.

[0005] The technical solution adopted by the present invention to solve its technical problems is as follows: An explosion-proof valve includes a valve body, an explosion-proof shell and a pilot assembly. A valve cavity is provided inside the valve body. An intake port A, a working port A and an exhaust port A communicating with the valve cavity are opened on the valve body. A valve rod is slidably arranged in the valve cavity. The pilot assembly includes a pilot seat and a micro solenoid valve. The pilot seat is fixed on the valve body. A piston cavity is provided inside the pilot seat. A piston is slidably arranged in the piston cavity. The end of the valve rod passes through the valve body and abuts against the piston; The explosion-proof shell is hermetically connected to the pilot seat. The micro solenoid valve is accommodated in the explosion-proof shell. The micro solenoid valve is provided with an intake port B, a working port B and an exhaust port B; The intake port A and the intake port B are communicated through an intake passage. The piston cavity and the working port B are communicated through a pilot passage. The exhaust port A and the exhaust port B are communicated through an exhaust passage; A manual rod for opening and closing the pilot passage is provided on the pilot seat.

[0006] Further, the micro solenoid valve is a two-way three-way solenoid valve.

[0007] Further, a boss is provided on the pilot seat. The micro solenoid valve is installed on the boss. The boss extends into the explosion-proof shell; Facilitate the installation of the micro solenoid valve and ensure the sealing performance between the pilot seat and the explosion-proof shell.

[0008] Further, an installation cavity for accommodating the micro solenoid valve is provided inside the explosion-proof shell. A mating hole, a first loading and unloading hole and a second loading and unloading hole communicating with the installation cavity are opened on the explosion-proof shell. The mating hole and the first loading and unloading hole are arranged at the bottom end of the explosion-proof shell and are on the same axis. The mating hole corresponds to the boss. The second loading and unloading hole is arranged at the top end of the explosion-proof shell. The second loading and unloading hole is used for placing the micro solenoid valve into the installation cavity; An end cover and a first sealing cover are provided on the explosion-proof shell. The end cover seals the second loading and unloading hole. The first sealing cover seals the first loading and unloading hole; It not only ensures the sealing performance of the explosion-proof shell, but also makes the installation of the micro solenoid valve convenient, effectively improving the explosion-proof performance.

[0009] Further, a wiring terminal electrically connected to the micro solenoid valve is provided inside the installation cavity. A wiring hole corresponding to the wiring terminal is opened on the explosion-proof shell. A second sealing cover for sealing the wiring hole is provided on the explosion-proof shell; Facilitate the wiring of the micro solenoid valve and convenient control.

[0010] Further, a first sealing ring is provided between the explosion-proof shell and the pilot seat; Improve the sealing performance.

[0011] Furthermore, an installation hole communicating with the piston chamber is provided in the pilot seat. The manual rod is slidably arranged in the installation hole. A diversion hole communicating with the installation hole is provided at the inner end of the manual rod, and an operation part is provided at the outer end of the manual rod. The installation hole communicates with the pilot channel, and the installation hole communicates with the intake A port through a connecting channel. A first annular groove and a second annular groove are sequentially arranged on the manual rod from the inside to the outside. The first annular groove and the second annular groove are respectively arranged corresponding to the pilot channel and the connecting channel. The second annular groove communicates with the diversion hole through a through hole, which is convenient for controlling the opening and closing of the pilot channel.

[0012] Furthermore, a sliding groove is also provided on the manual rod. The sliding groove includes a sliding end and a limiting end. The sliding end is arranged parallel to the extending direction of the manual rod, and the limiting end is arranged perpendicular to the sliding end. The limiting end is arranged close to the operation part. A limiting rod slidably matched with the sliding groove is provided in the pilot seat. A spring is provided in the installation hole. The spring always has a tendency to move the manual rod outwards and makes the side wall of the sliding end abut against the limiting rod, which is convenient for the reset of the manual rod and convenient for operation.

[0013] Furthermore, the operation part is a "one"-shaped opening groove exposed outside the pilot seat, which makes the operation convenient and is convenient for controlling the sliding of the manual rod.

[0014] The beneficial effects of the present invention are as follows: First, by accommodating the micro solenoid valve in the explosion-proof shell, the micro solenoid valve is provided with an intake B port, a working B port and an exhaust B port. The intake A port and the intake B port are communicated through an intake channel. The piston chamber and the working B port are communicated through a pilot channel. The exhaust A port and the exhaust B port are communicated through an exhaust channel. The micro solenoid valve can control the on-off of the pilot channel, control whether the gas flows to the piston chamber, thereby controlling the sliding of the piston and simultaneously reversing the valve rod. Thus, the micro solenoid valve replaces the function of the pilot head in the prior art. There is no need to consider the problem of the stroke of the moving iron core. Just controlling the micro solenoid valve can smoothly conduct or close the gas in the pilot channel, solving the problem of large processing difficulty in the prior art and effectively reducing the processing difficulty. Second, the micro solenoid valve is a relatively mature technology, which can be easily obtained in the market, has a relatively low price, and has a simple structure and fewer components, effectively reducing the cost, being more convenient and fast to install, avoiding the redundancy of the structure, improving the sealing performance and making the explosion-proof effect better. Third, a manual rod for opening and closing the pilot channel is provided on the pilot seat, which is convenient for manually controlling the opening or closing of the pilot channel, convenient for emergency operation and improving the safety performance. Generally speaking, the present invention has the advantages of convenient processing, fast installation, low manufacturing cost, high sealing performance and good explosion-proof effect. Description of the Drawings

[0015] Figure 1 is the overall structural schematic diagram of the present invention.

[0016] Figure 2 is the axonometric schematic diagram of the present invention.

[0017] Figure 3 is the exploded schematic diagram of the present invention.

[0018] Figure 4 is the top view schematic diagram of the present invention.

[0019] Figure 5 is Figure 4 the sectional view taken along W-W in

[0020] Figure 6 is Figure 4 the sectional view taken along X-X in

[0021] Figure 7 is Figure 4 the sectional view taken along Y-Y in

[0022] Figure 8 is Figure 7 the sectional view taken along Z-Z in

[0023] Figure 9 is the structural schematic diagram of the explosion-proof shell in the present invention.

[0024] Figure 10 is the structural schematic diagram of the manual rod in the present invention.

[0025] As shown in the figure: 1-valve body; 1.1-valve cavity; 1.2-intake port A; 1.3-working port A; 1.4-exhaust port A; 2-explosion-proof shell; 2.1-mounting cavity; 2.2-mating hole; 2.3-first loading and unloading hole; 2.4-second loading and unloading hole; 2.5-wiring hole; 3-valve rod; 4-pilot seat; 4.1-piston cavity; 4.2-intake passage; 4.3-pilot passage; 4.4-exhaust passage; 4.5-boss; 4.6-mounting hole; 4.7-connecting passage; 5-micro solenoid valve; 5.1-intake port B; 5.2-working port B; 5.3-exhaust port B; 6-piston; 7-manual rod; 7.1-diversion hole; 7.2-operation part; 7.3-first annular groove; 7.4-second annular groove; 7.5-through hole; 7.6-chute; 7.61-sliding end; 7.62-limiting end; 8-end cover; 9-first cover; 10-wiring terminal; 11-second cover; 12-first sealing ring; 13-limiting rod; 14-spring; 15-second sealing ring; 16-third sealing ring. Detailed Embodiments

[0026] For a more intuitive and complete understanding of the technical solution of the present invention, the non-limiting feature description is as follows in combination with the accompanying drawings of the present invention:

[0027] AsFigures 1 to 10 As shown in the figure, an explosion-proof valve includes a valve body 1, an explosion-proof shell 2 and a pilot assembly. A valve cavity 1.1 is provided inside the valve body 1. An air inlet A port 1.2, a working A port 1.3 and an exhaust A port 1.4 communicating with the valve cavity 1.1 are opened on the valve body 1. A valve rod 3 is slidably arranged in the valve cavity 1.1. The pilot assembly includes a pilot seat 4 and a micro solenoid valve 5. The pilot seat 4 is fixed on the valve body 1. A piston cavity 4.1 is provided inside the pilot seat 4. A piston 6 is slidably arranged in the piston cavity 4.1. The end of the valve rod 3 passes through the valve body 1 and abuts against the piston 6; The explosion-proof shell 2 is sealingly connected to the pilot seat 4. The micro solenoid valve 5 is accommodated in the explosion-proof shell 2. The micro solenoid valve 5 is provided with an air inlet B port 5.1, a working B port 5.2 and an exhaust B port 5.3; The air inlet A port 1.2 and the air inlet B port 5.1 are communicated through an air inlet channel 4.2. The piston cavity 4.1 and the working B port 5.2 are communicated through a pilot channel 4.3. The exhaust A port 1.4 and the exhaust B port 5.3 are communicated through an exhaust channel 4.4; A manual rod 7 for opening and closing the pilot channel 4.3 is provided on the pilot seat 4.

[0028] It is worth mentioning that the pilot assembly is not limited to the structure arranged on one side of the valve body 1 in the attached drawing. Two pilot assemblies can also be provided and arranged on both sides of the valve body 1 respectively; The valve body 1 is not limited to a two-position three-way valve or a two-position five-way valve, and can be other reversing valves.

[0029] Specifically, the micro solenoid valve 5 adopts a two-position three-way solenoid valve. For its specific structure and working principle, reference can be made to the "micro solenoid valve" disclosed in Chinese Patent Application No. CN200810063147.X, which will not be elaborated here one by one.

[0030] A boss 4.5 is provided on the pilot seat 4. The micro solenoid valve 5 is installed on the boss 4.5, and the boss 4.5 extends into the explosion-proof shell 2.

[0031] An installation cavity 2.1 for accommodating the micro solenoid valve 5 is provided inside the explosion-proof shell 2. A mating hole 2.2, a first loading and unloading hole 2.3 and a second loading and unloading hole 2.4 communicating with the installation cavity 2.1 are opened on the explosion-proof shell 2. The mating hole 2.2 and the first loading and unloading hole 2.3 are arranged at the bottom end of the explosion-proof shell 2 and are on the same axis. The mating hole 2.2 corresponds to the boss 4.5. The second loading and unloading hole 2.4 is arranged at the top end of the explosion-proof shell 2. The second loading and unloading hole 2.4 is used for placing the micro solenoid valve 5 into the installation cavity 2.1; An end cover 8 and a first sealing cover 9 are provided on the explosion-proof shell 2. The end cover 8 seals the second loading and unloading hole 2.4, and the first sealing cover 9 seals the first loading and unloading hole 2.3.

[0032] A wiring terminal 10 electrically connected to the micro solenoid valve 5 is provided inside the installation cavity 2.1. A wiring hole 2.5 corresponding to the wiring terminal 10 is opened on the explosion-proof shell 2. A second sealing cover 11 for sealing the wiring hole 2.5 is provided on the explosion-proof shell 2.

[0033] Normally, when installing the micro solenoid valve 5, first fix the explosion-proof shell 2 on the pilot seat 4 with screws, and make the boss 4.5 pass through the mating hole 2.2. Press a first sealing ring 12 between the pilot seat 4 and the explosion-proof shell 2. Then place the micro solenoid valve 5 into the installation cavity 2.1 through the second loading and unloading hole 2.4, making the micro solenoid valve 5 correspond to the boss 4.5. Insert a screw through the first loading and unloading hole 2.3 and tighten it to fix the micro solenoid valve 5 on the boss 4.5. Then seal and install the first cover 9 on the first loading and unloading hole 2.3. Immediately place the terminal 10 into the installation cavity 2.1 to make electrical connection with the micro solenoid valve 5. Then pass the wire through the wiring hole 2.5, and then seal and install the second cover 11 on the wiring hole 2.5. Finally, seal and install the end cover 8 on the first loading and unloading hole 2.3, thus completing the installation of the micro solenoid valve 5.

[0034] It should be noted that the second cover 11 is provided with a hole for the wire to pass through and a sealing ring for sealing the wire; or an in-built wireless device is adopted to be electrically connected with the controller to replace the wire, making the explosion-proof shell 2 have higher sealing performance and better explosion-proof performance.

[0035] A first sealing ring 12 is provided between the explosion-proof shell 2 and the pilot seat 4, and the first sealing ring 12 is sleeved and mated with the boss 4.5; a corresponding second sealing ring 15 is provided between the pilot seat 4 and the valve body 1.

[0036] The pilot seat 4 is provided with an installation hole 4.6 communicating with the piston cavity 4.1. The manual rod 7 is slidably arranged in the installation hole 4.6. The inner end of the manual rod 7 is provided with a diversion hole 7.1 communicating with the installation hole 4.6, and the outer end of the manual rod 7 is provided with an operation part 7.2. The installation hole 4.6 communicates with the pilot channel 4.3. The installation hole 4.6 is communicated with the intake port A 1.2 through a connection channel 4.7. The manual rod 7 is successively provided with a first annular groove 7.3 and a second annular groove 7.4 from inside to outside. The first annular groove 7.3 and the second annular groove 7.4 are respectively arranged in one-to-one correspondence with the pilot channel 4.3 and the connection channel 4.7. The second annular groove 7.4 is communicated with the diversion hole 7.1 through a through hole 7.5.

[0037] Specifically, a third sealing ring 16 corresponding to the first annular groove 7.3 and the second annular groove 7.4 is sleeved on the manual rod 7.

[0038] The manual rod 7 is further provided with a sliding groove 7.6. The sliding groove 7.6 includes a sliding end 7.61 and a limiting end 7.62. The sliding end 7.61 is arranged parallel to the extending direction of the manual rod 7, and the limiting end 7.62 is arranged perpendicular to the sliding end 7.61. The limiting end 7.62 is arranged close to the operation part 7.2. The pilot seat 4 is provided with a limiting rod 13 slidably mated with the sliding groove 7.6. A spring 14 is arranged in the installation hole 4.6. The spring 14 always has a tendency to move the manual rod 7 outwards and makes the side wall of the sliding end 7.61 abut against the limiting rod 13.

[0039] The operation part 7.2 is a "one"-shaped open groove exposed outside the pilot seat 4, and can also be a "cross"-shaped groove, a hexagonal groove, a quadrilateral column, or other structures corresponding to the corresponding wrench.

[0040] The specific working principle of the manual lever 7: Normally, under the elastic force of the spring 14, the side wall of the sliding end 7.61 abuts against the limiting lever 13, and the inner end of the manual lever 7 opens the pilot channel 4.3. When the micro solenoid valve 5 is opened, the gas in the pilot channel 4.3 can directly flow into the piston chamber 4.1 through the mounting hole 4.6. At this time, the gas in the connecting channel 4.7 flows to the first annular groove 7.3 to close the connecting channel 4.7; when it is necessary to change the gas flow direction, a "flat" screwdriver is correspondingly inserted into the operation part 7.2, pushed inward and then rotated by a certain angle, so that the manual lever 7 overcomes the elastic force of the spring 14, and the limiting lever 13 slides along the chute 7.6, so that the limiting lever 13 reaches inside the limiting end 7.62, thereby clamping the manual lever 7 here. At this time, the pilot channel 4.3 corresponds to the first annular groove 7.3 to close the pilot channel 4.3, and the connecting channel 4.7 corresponds to the second annular groove 7.4. The gas in the connecting channel 4.7 sequentially flows into the piston chamber 4.1 through the through hole 7.5, the diversion hole 7.1 and the mounting hole 4.6; when it is necessary to reset the manual lever 7, a "flat" screwdriver is also correspondingly inserted into the operation part 7.2, and after rotating in the reverse direction, under the elastic force of the spring 14, the manual lever 7 will return to its original position.

[0041] The specific working principle of the present invention: Normally, the intake port A 1.2 is connected to the air source, the working port A 1.2 is correspondingly connected to a cylinder or other actuator, the exhaust port A 1.4 is connected to a muffler or directly to the atmosphere. A part of the gas at the intake port A 1.2 will flow into the valve chamber 1.1, a part of the gas will flow into the connecting channel 4.7, and another part of the gas will flow into the micro solenoid valve 5 through the intake channel 4.2 and the intake port B 5.2. At this time, the pilot channel 4.3 is closed by the micro solenoid 5, and the intake channel 4.2 is closed by the manual lever 7; when the micro solenoid valve 5 is controlled to be powered on, the pilot channel 4.3 is turned on, and the gas flows through the mounting hole 4.6 into the piston chamber 4.1, so that the piston 6 pushes the valve stem 3 to slide and change the direction; or manually operate the manual lever 7 (the specific operation process can refer to the specific working principle of the above manual lever 7), so that the connecting channel 4.7 is opened and the pilot channel 4.3 is closed, so that the gas at the connecting channel 4.7 sequentially flows into the piston chamber 4.1 through the through hole 7.5, the diversion hole 7.1 and the mounting hole 4.6, and the valve stem 3 can also be changed in direction.

[0042] The above is only the preferred embodiment of the present invention. Therefore, all equivalent changes or modifications made according to the structure, characteristics and principles described in the scope of the patent application of the present invention are included in the scope of the patent application of the present invention.

Claims

1. An explosion-proof valve, comprising a valve body (1), an explosion-proof housing (2) and a pilot assembly. A valve cavity (1.1) is provided inside the valve body (1). An intake port A (1.2), a working port A (1.3) and an exhaust port A (1.4) that communicate with the valve cavity (1.1) are formed on the valve body (1). A valve rod (3) is slidably arranged inside the valve cavity (1.1), characterized in that: The pilot assembly includes a pilot seat (4) and a micro solenoid valve (5). The pilot seat (4) is fixed to the valve body (1). A piston chamber (4.1) is provided in the pilot seat (4). A piston (6) is slidably provided in the piston chamber (4.1). The end of the valve stem (3) passes through the valve body (1) and abuts against the piston (6) for cooperation; The explosion-proof housing (2) is sealingly connected to the pilot seat (4). The micro solenoid valve (5) is accommodated in the explosion-proof housing (2). The micro solenoid valve (5) is provided with an intake port B (5.1), a working port B (5.2) and an exhaust port B (5.3); The intake port A (1.2) and the intake port B (5.1) are connected through an intake passage (4.2). The piston chamber (4.1) and the working port B (5.2) are connected through a pilot passage (4.3). The exhaust port A (1.4) and the exhaust port B (5.3) are connected through an exhaust passage (4.4); A manual rod (7) for opening and closing the pilot passage (4.3) is provided on the pilot seat (4); An installation hole (4.6) communicating with the piston chamber (4.1) is provided in the pilot seat (4). The manual rod (7) is slidably arranged in the installation hole (4.6). A diversion hole (7.1) communicating with the installation hole (4.6) is provided at the inner end of the manual rod (7). An operation part (7.2) is provided at the outer end of the manual rod (7); The installation hole (4.6) communicates with the pilot passage (4.3). The installation hole (4.6) is connected to the intake port A (1.2) through a connection passage (4.7). A first annular groove (7.3) and a second annular groove (7.4) are sequentially arranged on the manual rod (7) from inside to outside. The first annular groove (7.3) and the second annular groove (7.4) are respectively arranged corresponding to the pilot passage (4.3) and the connection passage (4.7). The second annular groove (7.4) communicates with the diversion hole (7.1) through a through hole (7.5).

2. The explosion-proof valve according to claim 1, wherein: The micro solenoid valve (5) is a two-position three-way solenoid valve.

3. An explosion-proof valve according to claim 1, characterized in that: A boss (4.5) is provided on the pilot seat (4). The micro solenoid valve (5) is installed on the boss (4.5). The boss (4.5) extends into the explosion-proof housing (2).

4. An explosion-proof valve according to claim 3, characterized in that: An installation cavity (2.1) for accommodating the micro solenoid valve (5) is provided in the explosion-proof housing (2). A mating hole (2.2), a first loading and unloading hole (2.3) and a second loading and unloading hole (2.4) communicating with the installation cavity (2.1) are provided on the explosion-proof housing (2). The mating hole (2.2) and the first loading and unloading hole (2.3) are arranged at the bottom end of the explosion-proof housing (2) and are on the same axis. The mating hole (2.2) is arranged corresponding to the boss (4.5). The second loading and unloading hole (2.4) is arranged at the top end of the explosion-proof housing (2). The second loading and unloading hole (2.4) is for the micro solenoid valve (5) to be placed into the installation cavity (2.1); The explosion-proof housing (2) is provided with an end cover (8) and a first sealing cover (9). The end cover (8) seals the second loading and unloading hole (2.4), and the first sealing cover (9) seals the first loading and unloading hole (2.3).

5. An explosion-proof valve according to claim 4, characterized in that: A terminal (10) electrically connected to the micro solenoid valve (5) is provided in the installation cavity (2.1). A wiring hole (2.5) corresponding to the terminal (10) is formed in the explosion-proof housing (2), and a second sealing cover (11) for sealing the wiring hole (2.5) is provided on the explosion-proof housing (2).

6. An explosion-proof valve according to claim 4, characterized in that: A first sealing ring (12) is provided between the explosion-proof housing (2) and the pilot seat (4).

7. An explosion-proof valve according to claim 1, characterized in that: A chute (7.6) is further provided on the manual rod (7). The chute (7.6) includes a sliding end (7.61) and a limiting end (7.62). The sliding end (7.61) is arranged parallel to the extending direction of the manual rod (7), the limiting end (7.62) is perpendicular to the sliding end (7.61), and the limiting end (7.62) is arranged close to the operating part (7.2). A limiting rod (13) slidably matched with the chute (7.6) is provided in the pilot seat (4). A spring (14) is provided in the installation hole (4.6). The spring (14) always has a tendency to move the manual rod (7) outward, and makes the side wall of the sliding end (7.61) abut against the limiting rod (13).

8. An explosion-proof valve according to claim 1, characterized in that: The operating part (7.2) is a "one"-shaped open groove exposed outside the pilot seat (4).

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