Vacuum detection device for silicone adhesive dispersion machine

Abstract

The utility model discloses a vacuum detection device for a silicone adhesive dispersion machine, and relates to the technical field of silicone adhesive production equipment. A silicone adhesive dispersion machine vacuum detection device comprises a display host, a detection mechanism and a transmission line, the detection mechanism comprises a shell and a sensing module installed on the inner side of the shell, the sensing module comprises a sensing chip, a cavity piece and a capacitance film, and the capacitance film encloses and seals the cavity piece to form a constant pressure cavity with a low vacuum environment. When the vacuum degree in the dispersion machine is increased, the extending and sinking degree of the capacitance film towards the constant-voltage cavity is gradually reduced, and the capacitance value of the capacitance film changes along with the different extending and sinking degrees of the capacitance film, so that the sensing chip can calculate the air pressure value of the inner side of the dispersion machine according to the capacitance value of the capacitance film at the moment; moreover, the influence of heat radiation on the sensing module can be effectively prevented, the measurement error is reduced, and the accuracy of vacuum detection is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of silicone adhesive production equipment, in particular to a vacuum detection device for a silicone adhesive dispersing machine. Background Art

[0002] At present, in the production and processing of silicone rubber, the staff will add various raw materials into the disperser in proportion according to the process requirements, and then use the disperser to stir and mix the silicone rubber raw materials at high speed. In order to prevent air or moisture from causing side reactions between some of the silicone rubber raw materials and reduce the impact on the mixing effect, the disperser needs to maintain a vacuum environment during the mixing process. Therefore, the silicone rubber disperser is equipped with a detection device for detecting the vacuum degree in the disperser, and a vacuum gauge is generally used for detection.

[0003] The working principle of a traditional vacuum gauge is to change the thermal conductivity of the heating wire in the vacuum gauge by changing the pressure of the surrounding gas. Specifically, when the vacuum gauge is in a vacuum state, the gas molecules near the heating wire have low density and low pressure, and the thermal conductivity of the heating wire decreases. As the thermal conductivity of the heating wire decreases, the heat emitted by the heating wire will also decrease, so the temperature of the heating wire will gradually increase and the resistance value will also decrease. After converting between electricity and pressure, the pressure around the vacuum gauge can be obtained.

[0004] In the existing silicone adhesive stirring process, it is generally necessary to heat the silicone adhesive being stirred, which can reduce the shear viscosity of the colloid and make the mixing more complete. However, the heated silicone adhesive will emit a certain amount of heat radiation toward the inside of the disperser, and this heat radiation will further change the density of the gas molecules in the space where the heating wire is located, and will also directly affect the heating wire itself, which will not only reduce the sensitivity of the vacuum gauge, but also easily cause detection errors and low detection accuracy. Utility Model Content

[0005] In order to improve the accuracy of vacuum detection, the present application provides a vacuum detection device for a silicone adhesive disperser.

[0006] The vacuum detection device for a silicone adhesive dispersing machine provided in this application adopts the following technical solution:

[0007] A vacuum detection device for a silicone adhesive dispersing machine, comprising a display host, a detection mechanism and a transmission line, wherein the transmission line is used to electrically connect the display host and the detection mechanism;

[0008] The detection mechanism includes a housing and a sensing module for detecting the vacuum degree. One end of the housing is provided with a detection air hole. The sensing module is arranged inside the housing and divides the inside of the housing into a first air chamber and a second air chamber. The first air chamber and the second air chamber are interconnected. The first air chamber is located on the side of the sensing module facing the detection air hole, and the first air chamber is communicated with the measured environment through the detection air hole. A partition is further arranged in the housing. The partition encloses and seals one end of the second air chamber away from the sensing module and forms a third air chamber with one end of the housing away from the detection air hole. The housing is provided with a balance air hole, and the third air chamber is communicated with the external normal air pressure environment through the balance air hole.

[0009] The sensing module includes a sensing chip. The sensing chip is provided with a cavity part in a "凵" shape. The cavity part opens towards the first air chamber and is connected with a capacitive film with a certain ductility. The capacitive film encloses and seals the cavity part. A constant pressure chamber with a low vacuum environment is formed between the capacitive film and the cavity part. The capacitive film is electrically connected with the sensing chip. The display host is provided with a numerical display screen. The sensing chip is electrically connected with the numerical display screen through the transmission line.

[0010] By adopting the above technical solution, as the vacuum degree of the measured environment in the disperser increases, the air pressure in the first air chamber decreases. At this time, the degree of extension and depression of the capacitive film towards the constant pressure chamber with a low vacuum environment gradually decreases. According to the different degrees of depression of the capacitive film, the sensing chip can calculate the air pressure values of the first air chamber and the measured environment based on the capacitance value of the capacitive film at this time, and transmit the data to the numerical display screen through the transmission line for display. This vacuum detection method relies on the change of pressure to change the degree of extension and depression of the capacitive film, thereby changing the capacitance value of the capacitive film. The sensing chip only needs to detect the capacitance value of the capacitive film to calculate the air pressure values of the first air chamber and the measured environment. Thermal radiation cannot directly affect the degree of extension and depression of the capacitive film and its capacitance value, so it can effectively prevent the influence of thermal radiation on the sensing module, which is beneficial to reducing measurement errors and improving the accuracy of vacuum detection.

[0011] Optionally, the capacitive film is a multi-layer structure, which sequentially includes a first resin layer, a first silver-plated layer, a dielectric layer, a second silver-plated layer, and a second resin layer from top to bottom.

[0012] By adopting the above technical solution, using a multi-layer capacitive film, the first resin layer and the second resin layer can effectively protect the first silver-plated layer and the second silver-plated layer, reduce the influence of thermal radiation on the conductivity of the silver-plated layer, and also prevent the influence of thermal radiation on the dielectric properties of the dielectric layer, which is beneficial to reducing the measurement errors of the sensing module, thereby improving the accuracy of vacuum detection.

[0013] Optionally, the dielectric layer is a polyphenylene sulfide film with a thickness of 2 μm-4 μm.

[0014] By adopting the above technical solution, within this thickness range, the polyphenylene sulfide film has good ductility and resilience, and the polyphenylene sulfide film has very stable thermal and frequency characteristics, and the capacitance value is almost unaffected by temperature changes. It can effectively prevent the thermal radiation generated by the measured environment from affecting the dielectric properties of the capacitor film, which is beneficial to reduce measurement errors and improve the accuracy of vacuum detection.

[0015] Optionally, the air pressure in the constant pressure chamber is 10 2 Pa-10 5 Pa.

[0016] By adopting the above technical solution, when the air pressure in the constant pressure chamber is 10 2 Pa-10 5 Pa, the constant pressure chamber is in a low vacuum environment. Under normal conditions, the environment to be tested is under normal atmospheric pressure. At this time, the capacitor film will be extended and sunken toward the constant pressure chamber due to atmospheric pressure. The pressure value of the environment to be tested can be obtained according to the degree of the sunken capacitor film. Moreover, a low vacuum environment is easier to form than a high vacuum environment, making the production and preparation of the sensor module easier.

[0017] Optionally, a breathable heat-insulating cotton pad is fixedly disposed on the inner side of the shell, and the heat-insulating cotton pad is located at one end of the first air cavity away from the sensor module.

[0018] By adopting the above technical solution, the thermal insulation pad can effectively reduce the transfer of heat radiation, thereby helping to reduce the impact of heat radiation in the disperser on the sensor module and helping to reduce measurement errors.

[0019] Optionally, the shell includes an extended thin neck, an extended through slot is formed in the extended thin neck, and the detection air hole is communicated with the first air cavity through the extended through slot.

[0020] By adopting the above technical solution, the extended neck can move the sensor module further away from the disperser, further reducing the impact of heat radiation in the disperser on the sensor module, which is beneficial to reducing measurement errors.

[0021] Optionally, the shell includes a flange, and the detection air hole is opened on the flange.

[0022] By adopting the above technical solution, the detection mechanism can be fixedly installed on the disperser through the flange, and the flange connection can effectively improve the airtightness between the detection mechanism and the disperser, which is beneficial to reduce the measurement error caused by air leakage in the detection mechanism and improve the accuracy of vacuum detection.

[0023] Optionally, the detection mechanism further includes an alarm module for directly detecting the vacuum state, the alarm module including an end plate, an elastic reed and a fixed reed, the end plate being fixedly arranged in the third air cavity, the elastic reed being arranged in an arc shape on the side of the partition facing the end plate, a hemispherically sealed negative pressure cavity being formed between the elastic reed and the partition, the partition being provided with a negative pressure hole, the negative pressure cavity being interconnected with the second air cavity through the negative pressure hole, the fixed reed being arranged on the side of the end plate facing the partition, and under normal conditions, the elastic reed and the fixed reed abut against each other;

[0024] The display host is provided with an alarm light, and the elastic spring sheet and the fixed spring sheet are both electrically connected to the alarm light through the transmission line.

[0025] By adopting the above technical solution, the alarm module is set to directly display the vacuum status in the form of an alarm light, which is helpful for the staff to directly and quickly judge whether the vacuum degree required by the process has been reached in the test environment.

[0026] In summary, the technical solution of this application has at least one of the following beneficial effects:

[0027] 1. By setting a capacitor film that only relies on changes in air pressure to change its own extension and capacitance value, it can effectively prevent the influence of thermal radiation on the sensor module, which is beneficial to reduce measurement errors and improve the accuracy of vacuum detection.

[0028] 2. By setting up an alarm module, the vacuum status of the environment to be tested can be directly displayed in the form of an alarm light, which is helpful for the staff to directly and quickly determine whether the vacuum degree in the environment to be tested has reached the process requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of a vacuum detection device for a silicone adhesive disperser in an embodiment of the present application.

[0030] Figure 2 It is a cross-sectional view of a detection mechanism of a vacuum detection device for a silicone adhesive disperser in an embodiment of the present application.

[0031] Figure 3 It is a cross-sectional view of a capacitor film of a vacuum detection device of a silicone adhesive disperser in an embodiment of the present application.

[0032] Description of reference numerals:

[0033] 1. Display host; 11. Numerical display screen; 12. Alarm light; 2. Detection mechanism; 21. Shell; 211. Main shell; 2111. First air cavity; 2112. Second air cavity; 2113. Third air cavity; 2114. Balance air hole; 212. Flange; 2121. Detection air hole; 213. Extended thin neck; 2131. Extended thin groove; 22. Sensor module; 221. Sensor chip; 222. Cavity part; 2221, constant pressure cavity; 223, capacitor film; 2231, first resin layer; 2232, first silver-plated layer; 2233, dielectric layer; 2234, second silver-plated layer; 2235, second resin layer; 23, alarm module; 231, end plate; 232, elastic reed; 233, fixed reed; 24, partition; 241, negative pressure cavity; 242, negative pressure hole; 25, thermal insulation pad; 3, transmission line. DETAILED DESCRIPTION

[0034] The following is combined with Figure 1-3 This application is described in further detail.

[0035] The present application embodiment discloses a vacuum detection device for a silicone adhesive dispersing machine. Figure 1 A silicone adhesive disperser vacuum detection device comprises a display host 1, a detection mechanism 2 and a transmission line 3, wherein the display host 1 is used to display the relevant values ​​measured by the detection mechanism 2, the detection mechanism 2 is used to detect the internal environmental air pressure of the disperser, and the transmission line 3 is used to electrically connect the display host 1 and the detection mechanism 2.

[0036] Reference Figure 1 and Figure 2 The detection mechanism 2 includes a housing 21, a sensor module 22 and an alarm module 23, wherein the sensor module 22 is used to detect the vacuum degree, and the alarm module 23 is used to directly detect the vacuum state. Specifically, the housing 21 includes a main housing 211, a flange 212 and an extended narrow neck 213, the sensor module 22 and the alarm module 23 are both arranged in the main housing 211, the housing 21 is fixedly connected to the disperser through the flange 212, one end of the extended narrow neck 213 is connected to the flange 212, and the other end is connected to the main housing 211. The flange 212 is provided with a detection air hole 2121, and the detection air hole 2121 is connected to the environment to be tested inside the disperser, and the extended narrow neck 213 is provided with an extended through groove connecting the detection air hole 2121 and the inner side of the main housing 211, so that the environment to be tested can be connected to the inner side of the main housing 211 through the detection air hole 2121 and the extended through groove.

[0037] Reference Figure 2, the sensing module 22 divides the main housing 211 into a first air chamber 2111 and a second air chamber 2112. The first air chamber 2111 is located on the side of the sensing module 22 facing the extended thin neck 213, that is, the first air chamber 2111 communicates with the environment to be measured. The second air chamber 2112 is located on the side of the sensing module 22背离 the first air chamber 2111. A plurality of through holes are provided on the sensing module 22, so that the first air chamber 2111 and the second air chamber 2112 communicate with each other, that is, the environment to be measured, the first air chamber 2111, and the second air chamber 2112 are all in the same air pressure environment. A partition 24 is further provided on the inner side of the main housing 211. The partition 24 is provided on the side of the sensing module 22 away from the extended thin neck 213 and encloses and seals the end of the second air chamber 2112 away from the sensing module 22. A third air chamber 2113 is formed between the partition 24 and the end of the main housing 211 away from the extended thin neck 213. A balance air hole 2114 is provided at the end of the main housing 211 away from the extended thin neck 213. The third air chamber 2113 communicates with the external normal air pressure environment through the balance air hole 2114.

[0038] Refer to Figure 2 , in order to further reduce the influence of thermal radiation in the environment to be measured on the sensing module 22 and the alarm module 23 in the main housing 211, a breathable heat insulation cotton pad 25 is further provided on the inner side of the main housing 211. Specifically, the heat insulation cotton pad 25 is fixedly provided at the end of the first air chamber 2111 away from the sensing module 22, so as to effectively block the transmission of thermal radiation in the detection mechanism 2.

[0039] Refer to Figure 2 , the sensing module 22 includes a sensing chip 221. A "凵"-shaped cavity member 222 is provided on the sensing chip 221. The opening of the cavity member 222 faces the first air chamber 2111 and is covered with a capacitive film 223 with a certain ductility. The capacitive film 223 encloses and seals the cavity member 222 and forms a constant pressure chamber 2221. Both ends of the capacitive film 223 are electrically connected to the sensing chip 221. The display host 1 is provided with a numerical display screen 11. The sensing chip 221 is electrically connected to the numerical display screen 11 through a transmission line 3. Thus, the sensing chip 221 can calculate the corresponding air pressure value of the environment to be measured through the capacitance change in the capacitive film 223 and display it on the numerical display screen 11 of the display host 1 through the transmission line 3.

[0040] Specifically, the constant pressure chamber 2221 can maintain a low vacuum environment with an air pressure of 102Pa-105Pa, so that under normal conditions, the air pressure in the environment to be tested and the first air chamber 2111 are both normal atmospheric pressures, and at this time, the capacitor film 223 will be extended and sunken toward the constant pressure chamber 2221 due to the atmospheric pressure, and the extended capacitor film 223 has a corresponding capacitance value; and when the environment to be tested enters a vacuum state, the air pressure in the first air chamber 2111 also decreases accordingly, and at this time, the extension and depression degree of the capacitor film 223 toward the constant pressure chamber 2221 gradually decreases, and when the air pressure in the first air chamber 2111 is lower than the air pressure in the constant pressure chamber 2221, the capacitor film 223 will even extend and sunken toward the direction of the first air chamber 2111. Since the degree of depression of the capacitor film 223 is different, its own capacitance value will also change accordingly, so the sensor chip 221 only needs to detect the capacitance value of the capacitor film 223 to calculate the air pressure value of the first air chamber 2111 and the environment to be tested. In this embodiment, the air pressure in the constant pressure chamber 2221 is maintained at 102Pa.

[0041] Reference Figure 3 The capacitor film 223 has a multilayer structure, which includes a first resin layer 2231, a first silver-plated layer 2232, a dielectric layer 2233, a second silver-plated layer 2234 and a second resin layer 2235 in sequence, wherein the first resin layer 2231 and the second resin layer 2235 are both made of epoxy resin and coated on the first silver-plated layer 2232 and the second silver-plated layer 2234, respectively, so as to protect the first silver-plated layer 2232 and the second silver-plated layer 2234 and reduce the influence of heat radiation and other external factors on the first silver-plated layer 2232 and the second silver-plated layer 2234. The first silver-plated layer 2232 and the second silver-plated layer 2234 are both deposited on the surface of the dielectric layer by evaporation, and are used to be electrically connected to the sensor chip 221. The dielectric layer 2233 can be made of a polyphenylene sulfide film with a thickness of 2 μm-4 μm. In this thickness range, the polyphenylene sulfide film has good ductility and resilience, and has very stable thermal and frequency characteristics. The capacitance value is almost unaffected by temperature changes, and can effectively prevent the thermal radiation generated by the environment to be tested from affecting the detection structure. In this embodiment, the dielectric layer 2233 uses a polyphenylene sulfide film with a thickness of 4 μm.

[0042] Reference Figure 2The alarm module 23 includes a short plate, an elastic spring 232 and a fixed spring 233, wherein the end plate 231 is fixedly arranged in the third air cavity 2113, the elastic spring 232 is arc-shapedly arranged on the side of the partition 24 facing the end plate 231, and a hemispherical negative pressure cavity 241 is formed between the elastic spring 232 and the partition 24. The partition 24 is provided with a negative pressure hole 242, and the negative pressure cavity 241 is connected with the second air cavity 2112 through the negative pressure hole 242, so that the air pressure of the negative pressure cavity 241 is the same as the air pressure of the second air cavity 2112, the first air cavity 2111 and the environment to be measured. The fixed spring piece 233 is arranged on the side of the end plate 231 facing the partition 24. Under normal conditions, the air pressure in the environment to be tested and the negative pressure chamber 241 are both normal atmospheric pressure. At this time, the elastic spring piece 232 and the fixed spring piece 233 abut against each other and are electrically connected; when the environment to be tested enters a vacuum state, the air pressure in the negative pressure chamber 241 drops. Since the third air cavity 2113 is connected to the external normal air pressure environment through the balancing air hole 2114, the elastic spring piece 232 is pressurized and adsorbed to block the negative pressure hole 242. At this time, the elastic spring piece 232 and the fixed spring piece 233 are separated from each other, and the electrical connection is also disconnected.

[0043] Reference Figure 1 and Figure 2 , an alarm light 12 is also provided on the display host 1, and the elastic spring 232 and the fixed spring 233 are electrically connected to the alarm light 12 through the transmission line 3, so that when the environment to be tested is in a vacuum environment, the elastic spring 232 and the fixed spring 233 are disconnected from each other, and the alarm light 12 does not light up. When the environment to be tested leaks or other factors occur and the low-pressure vacuum environment cannot be maintained, the negative pressure on the elastic spring 232 is not enough to maintain its elastic deformation, so the elastic spring 232 will pop out in the direction of the fixed spring 233 and abut against the fixed spring 233. At this time, the circuit of the alarm light 12 is connected and lights up.

[0044] The implementation principle of a vacuum detection device for a silicone adhesive dispersing machine in the embodiment of the present application is as follows:

[0045] When it is necessary to perform vacuum testing on the disperser, align the flange 212 with the detection port of the disperser, and fix and seal the detection mechanism 2 on the disperser through the flange connection. At this time, the environment to be tested inside the disperser is connected to the first air cavity 2111 in the main shell 211 through the detection air hole 2121 and the extended groove 2131.

[0046] As the vacuum level of the environment to be tested in the disperser increases, the air pressure of the first air cavity 2111 and the second air cavity 2112 decreases, and the extent to which the capacitor film 223 extends and sinks toward the constant pressure cavity 2221 gradually decreases. According to the different degrees of depression of the capacitor film 223, the sensor chip 221 can calculate the air pressure value of the first air cavity 2111 and the environment to be tested according to the capacitance value of the capacitor film 223 at this time, and transmit the data to the numerical display screen 11 through the transmission line 3 for display. At the same time, the elastic spring 232 and the fixed spring 233 are disconnected from each other, and the alarm light 12 is off.

[0047] If the disperser is in a leaking state at this time and cannot maintain a vacuum environment with a target vacuum degree, the negative pressure on the elastic spring 232 is insufficient to maintain its elastic deformation. Therefore, the elastic spring 232 will pop out in the direction of the fixed spring 233 and abut against the fixed spring 233. At this time, the circuit of the alarm light 12 is connected and lights up, so the staff can directly know that the vacuum degree of the disperser has not met the process requirements.

[0048] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A vacuum detection device for a silicone adhesive dispersing machine, characterized in that: It includes a display host (1), a detection mechanism (2), and a transmission line (3). The transmission line (3) is used to electrically connect the display host (1) and the detection mechanism (2). The detection mechanism (2) includes a housing (21) and a sensing module (22) for detecting the vacuum degree value. One end of the housing (21) is provided with a detection air hole (2121). The sensing module (22) is arranged inside the housing (21) and divides the inside of the housing (21) into a first air chamber (2111) and a second air chamber (2112). The first air chamber (2111) and the second air chamber (2112) are communicated with each other. The first air chamber (2111) is located on the side of the sensing module (22) facing the detection air hole (2121), and the first air chamber (2111) is communicated with the measured environment through the detection air hole (2121). A partition (24) is also arranged in the housing (21). The partition (24) encloses and seals one end of the second air chamber (2112) away from the sensing module (22) and forms a third air chamber (2113) with one end of the housing (21) away from the detection air hole (2121). The housing (21) is provided with a balance air hole (2114), and the third air chamber (2113) is communicated with the external normal air pressure environment through the balance air hole (2114). The sensing module (22) includes a sensing chip (221). The sensing chip (221) is provided with a "U"-shaped cavity member (222). The cavity member (222) opens towards the first air chamber (2111) and is connected with a capacitive film (223) with a certain ductility. The capacitive film (223) encloses and seals the cavity member (222). A constant pressure chamber (2221) with a low vacuum environment is formed between the capacitive film (223) and the cavity member (222). The capacitive film (223) is electrically connected with the sensing chip (221). The display host (1) is provided with a numerical display screen (11). The sensing chip (221) is electrically connected with the numerical display screen (11) through the transmission line (3).

2. A vacuum detection device for a silicone adhesive dispersing machine according to claim 1, characterized in that: The capacitive film (223) is a multi-layer structure, which successively includes a first resin layer (2231), a first silver-plated layer (2232), a dielectric layer (2233), a second silver-plated layer (2234), and a second resin layer (2235) from top to bottom.

3. A vacuum detection device for a silicone adhesive dispersing machine according to claim 2, characterized in that: The dielectric layer (2233) is a polyphenylene sulfide film with a thickness of 2μm - 4μm.

4. A vacuum detection device for a silicone adhesive dispersing machine according to claim 1, characterized in that: The air pressure in the constant pressure chamber (2221) is 10 2 Pa-10 5 Pa.

5. A vacuum detection device for a silicone adhesive dispersing machine according to claim 1, characterized in that: An air-permeable heat-insulating cotton pad (25) is also fixedly arranged inside the housing (21). The heat-insulating cotton pad (25) is located at one end of the first air chamber (2111) away from the sensing module (22).

6. A vacuum detection device for a silicone adhesive dispersing machine according to claim 1, characterized in that: The housing (21) includes an extended thin neck (213). An extended through groove is arranged in the extended thin neck (213). The detection air hole (2121) is communicated with the first air chamber (2111) through the extended through groove.

7. A vacuum detection device for a silicone adhesive dispersing machine according to claim 1, characterized in that: The housing (21) comprises a flange (212), and the detection air hole (2121) is provided on the flange (212).

8. A vacuum detection device for a silicone adhesive dispersing machine according to claim 1, characterized in that: The detection mechanism (2) further comprises an alarm module (23) for directly detecting a vacuum state, the alarm module (23) comprising an end plate (231), an elastic reed (232) and a fixed reed (233), the end plate (231) being fixedly arranged in the third air cavity (2113), the elastic reed (232) being arranged in an arc shape on a side of the partition (24) facing the end plate (231), a hemispherical sealed negative pressure cavity (241) being formed between the elastic reed (232) and the partition (24), the partition (24) being provided with a negative pressure hole (242), the negative pressure cavity (241) being in communication with the second air cavity (2112) via the negative pressure hole (242), the fixed reed (233) being arranged on a side of the end plate (231) facing the partition (24), and in a normal state, the elastic reed (232) and the fixed reed (233) are in contact with each other; The display host (1) is provided with an alarm light (12), and the elastic spring sheet (232) and the fixed spring sheet (233) are both electrically connected to the alarm light (12) via the transmission line (3).

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