Power supply circuit and power supply cabinet of sand filter

Abstract

The utility model discloses a power supply circuit and a power supply cabinet of a sand filter, and the power supply circuit of the sand filter rapidly switches an AC main power supply circuit, a DC main power supply circuit and an AC standby power supply circuit through the logic combination of an inverter and a change-over switch. When the alternating current power supply loses power, the inverter can switch power supply to the direct current main power supply circuit; when the inverter breaks down, the change-over switch can switch power supply to the alternating-current standby power supply circuit, and the switching time is less than 50 ms specified by the short-time power loss time limit allowed by the PLC. It can be understood that the technical scheme of the utility model solves the problems that the switching time of the power supply of the UPS cabinet of the sand filter is long and the load needs to be powered off when the UPS cabinet is maintained, so that the power supply circuit of the sand filter can switch the power supply circuit with almost zero delay, the load does not need to be powered off when the power supply cabinet is maintained, and the production stability is greatly guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of electric power equipment in water plants, in particular to a power supply circuit and a power supply cabinet of a sand filter tank. Background Art

[0002] Sand filter filtration is a critical component of the water purification process at a waterworks. Currently, all equipment in the sand filter (valves, level gauges, turbidity meters, etc.) is controlled by a Programmable Logic Controller (PLC), which is powered by an Uninterruptible Power Supply (UPS). The maximum transient power outage allowed for continuous operation of the PLC is no more than 50ms. The switching time for the bypass power supply of the UPS is greater than 200ms, which is longer than the transient power outage allowed for the PLC. Furthermore, UPS maintenance requires power switching, which can cause a brief power outage to the PLC during this period. Therefore, the sand filter must be shut down and restarted in advance during UPS maintenance, significantly impacting normal production. Consequently, the long power switching time of the UPS and the need for load power outages during UPS maintenance are issues that urgently need to be addressed. Utility Model Content

[0003] The main purpose of the utility model is to provide a power supply circuit and a power supply cabinet for a sand filter, aiming to solve the problem that the power switching time of the UPS power supply cabinet of the sand filter is long and the load power outage is required during maintenance of the UPS power supply cabinet.

[0004] To achieve the above-mentioned purpose, the power supply circuit of the sand filter tank of the present invention includes:

[0005] A power supply, comprising an AC power supply and a DC power supply, wherein the AC power supply and the DC power supply are respectively used to provide electric power;

[0006] an inverter, wherein one input end of the inverter is connected to the AC power supply, a first switch is provided on the line between the inverter and the AC power supply, and another input end of the inverter is connected to the DC power supply, a second switch is provided on the line between the inverter and the DC power supply;

[0007] a switching switch, wherein the output end of the inverter is connected to one input end of the switching switch, the other input end of the switching switch is connected to the AC power supply, and the output end of the switching switch is used to connect to an external load;

[0008] The circuit formed by the AC power supply, the first switch, the inverter and the switching switch constitutes an AC main power supply circuit for supplying power to the external load;

[0009] The circuit formed by the DC power supply, the second switch, the inverter and the switching switch constitutes a DC main supply circuit for supplying power to the external load;

[0010] The circuit formed by the AC power supply and the switch constitutes an AC backup circuit for supplying power to the external load.

[0011] Optionally, an AC bypass circuit is formed between the AC power supply and the external load, and a third switch is provided on the AC bypass circuit, and the third switch is used to control the on and off of the formed AC bypass circuit.

[0012] Optionally, it further includes: an isolation transformer, wherein the isolation transformer is connected to the line between the inverter and the switching switch, and the isolation transformer is grounded.

[0013] Optionally, the system further comprises: a first single-pole double-throw switch and a second single-pole double-throw switch, wherein a fixed terminal of the first single-pole double-throw switch is connected to the isolation transformer, the other fixed terminal of the first single-pole double-throw switch is connected to a fixed terminal of the second single-pole double-throw switch, and a movable terminal of the first single-pole double-throw switch is connected to an input terminal of the switching switch;

[0014] The other fixed end of the second single-pole double-throw switch is connected to the output end of the switching switch, and the movable end of the second single-pole double-throw switch is used to connect to an external load.

[0015] Optionally, the device further comprises: a fourth switch;

[0016] The fourth switch is connected between the isolation transformer and an input terminal of the switching switch;

[0017] The fourth switch and the third switch are provided with a "two-choose-one" mechanical interlock.

[0018] Optionally, it also includes: an ammeter, a voltmeter and a current transformer;

[0019] The ammeter and the voltmeter are respectively connected to the AC main power supply circuit, the DC main power supply circuit, the AC backup power supply circuit and the AC bypass circuit;

[0020] The current transformer is connected to the AC main supply circuit, the DC main supply circuit, the AC backup supply circuit and the AC bypass circuit.

[0021] Optionally, it also includes: a controller, which is electrically connected to the inverter, the switching switch, the first switch, the second switch, the third switch, and the fourth switch, and the controller is used to control switching of the AC main supply circuit, the DC main supply circuit, the AC backup supply circuit, and the AC bypass circuit.

[0022] Optionally, the controller has a fault / status telesignaling module, which is electrically connected to the inverter and the switching switch, and is used to monitor the fault status of the inverter and the switching switch.

[0023] Optionally, it further includes: a lightning arrester, one end of which is connected to the AC power supply and the other end is grounded.

[0024] The utility model also provides a power supply cabinet for a sand filter tank, which uses the power supply circuit of any of the above-mentioned sand filter tanks.

[0025] In the technical solution of the present invention, the power supply circuit of the sand filter tank rapidly switches between the AC main supply circuit, the DC main supply circuit, and the AC backup supply circuit through a logical combination of an inverter and a switch. When the AC power fails, the inverter can switch the power supply to the DC main supply circuit; when the inverter fails, the switch can switch the power supply to the AC backup supply circuit, and the switching time is less than the 50ms specified by the PLC's short-term power outage limit. It can be understood that the technical solution of the present invention solves the problem of long power switching time of the UPS power cabinet of the sand filter tank, which requires load power outage during UPS power cabinet maintenance. The power supply circuit of the sand filter tank can switch the power supply circuit with almost zero delay, eliminating the need to shut down the load during power cabinet maintenance, greatly ensuring production stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0027] Figure 1 This is a schematic diagram of the structure of the power supply circuit of the sand filter tank according to one embodiment of the present utility model;

[0028] Figure 2 This is a circuit diagram of a power supply circuit of a sand filter tank according to an embodiment of the present utility model;

[0029] Figure 3 This is a circuit diagram of a control circuit of a power supply circuit of a sand filter tank according to an embodiment of the present invention.

[0030] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0033] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0034] In view of this, the main purpose of the utility model is to propose a power supply circuit for a sand filter tank, which aims to solve the problem that the power switching time of the UPS power cabinet of the sand filter tank is long and the load needs to be powered off during maintenance of the UPS power cabinet. The power supply circuit of the sand filter tank can switch the power supply circuit with almost zero delay, and there is no need to power off the load during maintenance of the power cabinet, which greatly ensures the stability of production.

[0035] See also Figure 1 、 Figure 2 As shown, in one embodiment of the present utility model, the power supply circuit of the sand filter includes: an AC power supply, a DC power supply, and a switching circuit, wherein the switching circuit includes an inverter VI and a switching switch SC;

[0036] One input end of the inverter VI is connected to the AC power supply, the other input end of the inverter VI is connected to the DC power supply, and the output end of the inverter VI is connected to an input end of the switch SC. The inverter VI is used to switch between the AC power supply and the DC power supply;

[0037] The other input end of the switching switch SC is connected to the AC power supply, and the output end of the switching switch SC is used to connect an external load. The switching switch SC is used to switch: the AC power supply / the DC power supply is supplied via the inverter VI, or the AC power supply is supplied directly without the inverter VI;

[0038] The technical solution of the present invention quickly switches the AC main supply circuit, DC main supply circuit and AC backup supply circuit through the logical combination of the inverter and the switching switch, and an additional bypass circuit is provided to deal with the switching switch failure.

[0039] It should be noted that the power supply circuit of the sand filter tank of the present invention is simpler than the power supply circuit of the sand filter tank commonly used now. It only uses the inverter AC power supply line switch QF10 (first switch), the inverter DC power supply line switch QF0 (second switch), the bypass switch (third switch) QF14, the inverter VI, and the switching switch SC to realize the switching of four power supply circuits: AC main supply circuit, DC main supply circuit, AC backup supply circuit and bypass circuit. The following are the application scenarios of the four power supply circuits:

[0040] When the power supply is normal, it is powered by 220V AC power supply;

[0041] When the AC power fails, the inverter VI switches to 220V DC power supply;

[0042] When the inverter VI fails and the output loses power, the switch SC switches to 220V AC power supply, and supplies power to the external load directly through the switch SC without passing through the inverter VI;

[0043] When the transfer switch SC fails and the output loses power, it switches to 220V AC power and supplies power to the external load directly without passing through the transfer switch SC.

[0044] It should also be noted that the main component parameters used in this utility model are:

[0045] (1) Online sine wave inverter VI: AC 220V, DC 220V dual power input / rated capacity 3kVA / AC / DC switching time 0ms;

[0046] (2) Switch SC: ATS / GTS fast switching switch, two AC 220V power inputs / rated current 63A / switching time ≤ 50ms;

[0047] As can be seen from the above information, the power supply circuit of the sand filter of the present invention is simple, significantly reducing the failure rate, making maintenance more convenient, and increasing the safety and reliability of the sand filter's power supply. The power switching times of the inverter VI and the transfer switch SC in the power supply circuit of the sand filter of the present invention are 0ms and ≤50ms, respectively, ensuring continuous power supply to the sand filter's PLC and reducing the risk of program errors and filter loss of control caused by prolonged transient power outages in the PLC. In summary, the power supply circuit of the sand filter of the present invention enables the power supply circuit of the sand filter to switch power with almost zero delay, eliminating the need to shut down the load during power cabinet maintenance, thereby greatly ensuring production stability. The rational logical combination of the transfer switch SC and the circuit breaker allows control components such as the inverter VI and transfer switch SC to be electrically isolated from the control circuit. By implementing certain safety measures, maintenance, repair, replacement, testing, and experimentation can be performed without interrupting the filter load, significantly improving work efficiency.

[0048] See also Figure 1 、 Figure 2 As shown, in one embodiment of the present invention, the power circuit of the sand filter uses a DC power supply (DC device cabinet) with a rated voltage of DC220V and a battery capacity of 38Ah. The battery providing the DC power supply uses a capacity of 38Ah, which makes the DC backup power supply last for 3 to 5 hours, providing sufficient time for troubleshooting and regular maintenance.

[0049] See also Figure 1 、 Figure 2 As shown, in one embodiment of the present invention, the power supply circuit of the sand filter tank further includes: a main power switch QF1, a main power supply incoming line switch QF12, a backup power supply incoming line switch QF13, and a switching outgoing line switch QF15;

[0050] The inverter DC power supply inlet switch QF0 is connected between the DC power supply and the inverter VI;

[0051] One end of the main power switch QF1 is connected to the AC power supply, and one end of the inverter AC power supply line switch QF10, the transfer switch backup power supply line switch QF13 and the bypass switch QF14 are connected in parallel to the other end of the main power switch QF1;

[0052] The other end of the inverter AC power supply line switch QF10 is connected to the inverter VI input terminal;

[0053] The other end of the switch backup power supply line switch QF13 is connected to the input end of the switch SC;

[0054] The other end of the bypass switch QF14 is used to connect to the external load;

[0055] The main power supply line switch QF12 of the switching switch is connected between the inverter VI and the switching switch SC;

[0056] The transfer switch output switch QF15 is connected between the transfer switch SC and the external load.

[0057] The current supply directions of the four power supply circuits are:

[0058] (1) When the two input power sources of inverter VI are normal, power is supplied to the external load via the bypass circuit inside inverter VI and the transfer switch SC. Power flow: 220V AC → main power switch QF1 → inverter VI AC power incoming line switch QF10 → inverter VI (bypass circuit output) → transfer switch SC main power incoming line switch QF12 → transfer switch SC (main power output) → transfer switch SC outgoing line switch QF15 → external load.

[0059] (2) When the input power of inverter VI fails, the DC power supply is supplied to the external load through the inverter circuit inside inverter VI and the transfer switch SC. The power supply flow is: 220V DC power supply → inverter VI DC power supply input switch QF0 → inverter VI ( / DC power supply switching time 0ms) → transfer switch SC main power supply input switch QF12 → transfer switch SC (main power supply output) → transfer switch SC output switch QF15 → external load.

[0060] (3) When the inverter VI output loses power due to a fault, power is supplied to the external load via the transfer switch SC. Power flow: → Main power switch QF1 → Transfer switch SC backup power supply input switch QF13 → Transfer switch SC (main / backup power supply switching time ≤ 50ms) → Transfer switch SC output switch QF15 → external load.

[0061] (4) When the output of the transfer switch SC fails and loses power, it can be manually operated to supply power to the external load through the bypass circuit. Power flow: → Main power switch QF1 → Bypass switch QF14 (QF11, QF12, QF13, and QF15 are all disconnected) → External load.

[0062] See also Figure 1 、 Figure 2As shown, in one embodiment of the present invention, a fixed terminal of a first single-pole double-throw switch QF11 is connected to an isolation transformer T, and the other fixed terminal of the first single-pole double-throw switch QF11 is connected to a fixed terminal of a second single-pole double-throw switch QF15. The movable terminal of the first single-pole double-throw switch QF11 is connected to the input terminal of a transfer switch SC; the other fixed terminal of the second single-pole double-throw switch QF15 is connected to the output terminal of the transfer switch SC, and the movable terminal of the second single-pole double-throw switch QF15 is connected to an external load. The first single-pole double-throw switch QF11 and the second single-pole double-throw switch QF15 are provided with a "two-choose-one" mechanical interlock, thereby forming a load non-power-off test circuit. The specific operation is as follows:

[0063] (1) Test Inverter VI:

[0064] Disconnect the main power supply incoming line switch QF12 (QF11 is disconnected) at the transfer switch SC, switching the transfer switch SC to the backup power supply. Power flows: → Main power switch QF1 → Transfer switch SC backup power incoming line switch QF13 → Transfer switch SC (main / backup power supply switching time 50ms) → Transfer switch SC outgoing line switch QF15 → Load busbar.

[0065] Operate the inverter VI and the two DC input power switches QF1 and QF0 to test the inverter VI's switching function. If repair, replacement, or testing is required, disconnect QF1 and QF0, which will disconnect the inverter VI from the control circuit.

[0066] (2) Test the switch SC

[0067] Disconnect the main power supply input switch QF12 of the transfer switch SC (QF11 is disconnected), switching the transfer switch SC to the backup power input. Close the bypass switch QF14, temporarily running the bypass power in parallel with the transfer switch SC output. Disconnect the output switch QF15 of the transfer switch SC, disconnecting the transfer switch SC output. Power is then supplied to the load busbar via the bypass circuit. Power flows from: → Main power switch QF1 → Bypass switch QF14 → Load busbar.

[0068] Operate the main and backup power input switches QF11 and QF13 of the transfer switch SC to perform a functional test on the transfer switch SC. If repair or replacement testing is required, disconnect the main and backup power input switches QF11, QF12, and QF13 of the transfer switch SC. This will disconnect the transfer switch SC from the control circuit.

[0069] See also Figure 1 、 Figure 2As shown, in one embodiment of the present invention, ammeter PA0 and voltmeter PV0 are connected between the DC power supply and the inverter VI; ammeter PA1 and voltmeter PV2 are connected between the AC power supply and the inverter VI, which can monitor the current value and voltage value of the AC power supply and the DC power supply at any time.

[0070] See also Figure 1 、 Figure 2 As shown, in one embodiment of the present invention, current transformer Ta0 is connected between the DC power supply and the inverter VI; current transformer Ta1 is connected between the AC power supply and the inverter VI. Current transformers Ta0 and Ta1 convert high current into low current in proportion, which facilitates instrument measurement and provides power for relay protection and automatic devices.

[0071] See also Figure 1 、 Figure 2 As shown, in one embodiment of the present invention, an isolation transformer T is connected between the inverter VI and the switch SC, and the isolation transformer T is grounded. The isolation transformer completely insulates the primary side from the secondary side, and also isolates the circuit to ensure power safety.

[0072] See also Figure 1 、 Figure 2 As shown, in one embodiment of the present invention, one end of the switch QF01 and the lightning arrester F is connected to the AC power supply, and the other end is grounded, which can effectively prevent lightning damage and ensure stable and safe power supply.

[0073] See also Figure 1 、 Figure 2 As shown, in one embodiment of the present invention, the main power supply incoming line switch QF12 and the bypass switch QF14 are provided with a "two-choose-one" mechanical interlock, which prohibits the main power supply incoming line switch QF12 and the bypass switch QF14 from being closed at the same time, thereby preventing the inverter VI output from being parallel to the bypass power supply.

[0074] See also Figures 1 to 3 As shown, in one embodiment of the present invention, the power supply circuit of the sand filter tank further includes: a controller, which controls the inverter VI DC power supply input switch QF0, the main power switch QF1, the inverter VI AC power supply input switch QF10, the transfer switch main power supply test switch QF11, the transfer switch main power supply input switch QF12, the transfer switch backup power supply input switch QF13, the bypass switch QF14, and the transfer switch output switch QF15, thereby forming a logical combination of "inverter VI internal bypass output, abnormality, DC fault and inverter fault" of the inverter VI and "main power supply input and backup power supply input" of the transfer switch SC, centrally controlling and testing the power supply circuit of the V-type sand filter tank, making maintenance work more convenient.

[0075] See also Figures 1 to 3As shown, in one embodiment of the present invention, the controller has a fault / status remote signaling module and a buzzer for the inverter VI and the switching switch SC, which can realize local and remote alarms. Workers can immediately know that the inverter VI and the switching switch SC have failed, and then respond quickly, switch the power supply circuit, and implement troubleshooting to ensure stable and safe power supply.

[0076] See also Figures 1 to 3 As shown, in one embodiment of the present invention, a power supply cabinet for a sand filter utilizes the power supply circuit of any of the sand filters described in the above embodiments. This power supply cabinet enables equipment maintenance, repair, replacement, testing, and other operations to be performed without powering off the load, eliminating the need to shut down or resume operation of the filter, thereby improving work efficiency.

[0077] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. All equivalent structural transformations made based on the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A power supply circuit for a sand filter, characterized in that: include: A power supply, comprising an AC power supply and a DC power supply, wherein the AC power supply and the DC power supply are respectively used to provide electric power; an inverter, wherein one input end of the inverter is connected to the AC power supply, a first switch is provided on the line between the inverter and the AC power supply, and another input end of the inverter is connected to the DC power supply, a second switch is provided on the line between the inverter and the DC power supply; a switching switch, wherein the output end of the inverter is connected to one input end of the switching switch, the other input end of the switching switch is connected to the AC power supply, and the output end of the switching switch is used to connect to an external load; The circuit formed by the AC power supply, the first switch, the inverter and the switching switch constitutes an AC main power supply circuit for supplying power to the external load; The circuit formed by the DC power supply, the second switch, the inverter and the switching switch constitutes a DC main supply circuit for supplying power to the external load; The circuit formed by the AC power supply and the switch constitutes an AC backup circuit for supplying power to the external load.

2. The power supply circuit of the sand filter according to claim 1, wherein: An AC bypass circuit is formed between the AC power supply and the external load. A third switch is provided on the AC bypass circuit. The third switch is used to control the on and off of the formed AC bypass circuit.

3. The power supply circuit of the sand filter according to claim 2, wherein: Also includes: An isolation transformer is connected to the line between the inverter and the switch, and the isolation transformer is grounded.

4. The power supply circuit of the sand filter according to claim 3, wherein: Also includes: a first single-pole double-throw switch and a second single-pole double-throw switch, wherein a fixed terminal of the first single-pole double-throw switch is connected to the isolation transformer, the other fixed terminal of the first single-pole double-throw switch is connected to a fixed terminal of the second single-pole double-throw switch, and a movable terminal of the first single-pole double-throw switch is connected to an input terminal of the switch; The other fixed end of the second single-pole double-throw switch is connected to the output end of the switching switch, and the movable end of the second single-pole double-throw switch is used to connect to an external load.

5. The power supply circuit of the sand filter according to claim 4, characterized in that: Also includes: Fourth switch; The fourth switch is connected between the isolation transformer and an input terminal of the switching switch; The fourth switch and the third switch are provided with a "two-choose-one" mechanical interlock.

6. The power supply circuit of the sand filter according to claim 2, wherein: Also includes: Ammeters, voltmeters and current transformers; The ammeter and the voltmeter are respectively connected to the AC main power supply circuit, the DC main power supply circuit, the AC backup power supply circuit and the AC bypass circuit; The current transformer is connected to the AC main supply circuit, the DC main supply circuit, the AC backup supply circuit and the AC bypass circuit.

7. The power supply circuit of the sand filter according to claim 5, wherein: Also includes: A controller is electrically connected to the inverter, the switching switch, the first switch, the second switch, the third switch, and the fourth switch, and is used to control switching of the AC main supply circuit, the DC main supply circuit, the AC backup supply circuit, and the AC bypass circuit.

8. The power supply circuit of the sand filter according to claim 7, wherein: The controller has a fault / status remote signaling module, which is electrically connected to the inverter and the switch, and is used to monitor the fault status of the inverter and the switch.

9. The power supply circuit of the sand filter according to any one of claims 1, wherein: Also includes: A lightning arrester, one end of which is connected to an AC power supply and the other end is grounded.

10. A power supply cabinet for a sand filter, characterized in that: A power supply circuit for a sand filter according to any one of claims 1 to 9.

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