Accident ventilation control system for small hazardous chemical substance warehouse

Abstract

The utility model discloses an accident ventilation control system for a small hazardous chemical substance warehouse. The accident ventilation control system comprises a main electric box and an explosion-proof change-over switch, the main electric box is provided with a gas concentration automatic alarm contact, an emergency starting switch, a relay, a contactor and the like; the relay is used for linking the contactor to be closed after the emergency starting switch is pressed or the gas concentration automatic alarm contact is triggered; the contactor is communicated with a forced start phase line; the explosion-proof switch is installed on the box surface of a main electric box of a corresponding fan service reservoir area, the explosion-proof switch is a multifunctional change-over switch, is provided with an opening position, a maintenance position and a standby position, and can realize conversion of the fan among three modes of opening, maintenance and standby, the maintenance position has a fan sudden stop function, and a line of the standby position is communicated with a forced start phase line. The construction cost of the scheme only accounts for about 1 / 3 of the cost of a traditional construction scheme, the personnel evacuation time only accounts for 1 / 5 of the traditional accident evacuation time, and both the economy and the safety are greatly improved.

Description

Technical Field

[0001] The utility model relates to the field of pharmaceutical factory building construction, and in particular to an accident ventilation control system for a small hazardous chemical warehouse. Background Art

[0002] According to national regulations, hazardous chemical warehouses need to be equipped with emergency ventilation systems. Usually, HVAC professionals need to set up two main and standby exhaust fans for each warehouse in the hazardous chemical warehouse. Only one of the two exhaust fans is usually turned on. After the gas detector detects a material leak alarm, the standby exhaust fan is automatically started, and then both exhaust fans can be put into exhaust and ventilation at the same time. The electrical profession needs to set up independent control buttons for each exhaust fan, and according to the requirements of the regulations, control buttons need to be set up both indoors and outdoors. HVAC and electrical work together to complete the emergency ventilation work of the entire hazardous chemical warehouse. In actual construction operations, the design and construction are usually carried out in accordance with the emergency ventilation chapter in 16D303-2: "Common Fan Control Circuit Diagram". This construction plan is more suitable for large-scale production workshops, but when applied to hazardous chemical warehouses with relatively small volumes, there will be shortcomings such as excessive pipeline laying, complex construction, and complex operation, which are specifically reflected in the following aspects:

[0003] 1. Excessive number of fans, low power (generally no more than 1.1 kW), and high wiring requirements. Hazardous chemicals need to be stored in separate warehouses, resulting in a small area for each warehouse. However, a single hazardous chemicals warehouse has numerous rooms. Each room requires both a main and backup exhaust fan, each equipped with its own switch system, resulting in excessive piping and wiring requirements.

[0004] 2. If each exhaust fan is equipped with start and stop buttons indoors and outdoors in accordance with the specifications, the number of buttons will be at least twice the number of exhaust fans, and the number of equipment and piping and wiring will be too large.

[0005] 3. When an accident occurs and all exhaust fans need to be turned on for emergency ventilation, since the outdoor switches are relatively scattered, turning them all on will be very time-consuming, which is contrary to the safety requirement of timely evacuation of personnel. Utility Model Content

[0006] To address these issues, this utility model discloses a small-scale hazardous chemical warehouse emergency ventilation control system. This solution's construction cost is only about one-third of traditional construction solutions, and its evacuation time is only one-fifth of traditional emergency evacuation time, significantly improving both economics and safety.

[0007] A small hazardous chemicals warehouse accident ventilation control system, including a main electrical box and an explosion-proof transfer switch;

[0008] The main electrical box is provided with a gas concentration automatic alarm contact, an emergency start switch, a relay and a contactor. The relay is used to link the contactor to close after pressing the emergency start switch or triggering the gas concentration automatic alarm contact; the contactor is connected to the forced phase line; the explosion-proof switch is installed on the main electrical box surface of the corresponding fan service area. The explosion-proof switch is a multi-functional conversion switch, which is provided with an open position, a maintenance position and a standby position, which can realize the conversion of the fan between the three modes of opening, maintenance and standby. The maintenance position has an emergency stop function for the fan, and the line of the standby position is connected to the forced phase line.

[0009] Preferably, the control system further comprises an explosion-proof wire box, in which a terminal block is provided, and the fan circuit is T-connected with the corresponding normal phase line, forced-start phase line and protection line in the explosion-proof wire box.

[0010] Preferably, the emergency start switch is a box surface self-locking switch that requires manual reset.

[0011] Preferably, the main electrical box is wall-mounted outdoors, and the shell of the main electrical box adopts an explosion-proof structure.

[0012] Preferably, a circuit breaker and a fuse for the exhaust fan are also provided in the main electrical box.

[0013] The working method of the above control system is as follows:

[0014] Mode 1, normal ventilation mode: the main electrical box circuit breaker is closed, the normal phase line is energized, the contactor does not operate, the forced start phase line is not energized, the explosion-proof switch rotary button is in the open position, the exhaust fan draws power from the normal phase line and is powered and running; when the exhaust fan needs to be stopped, the explosion-proof switch conversion button is placed in the standby position;

[0015] Mode 2, Maintenance / Emergency Stop Mode: When the on-site explosion-proof switch conversion knob is in the maintenance position, the exhaust fan cannot be powered from the normal phase line L, nor can it be powered from the forced phase line L'. In conjunction with the maintenance position padlock, the fan is prevented from being accidentally energized, and the corresponding motor can be repaired on-site; at the same time, this position also serves as an emergency stop position. When there is a motor failure on site and the exhaust fan needs to be urgently powered off, the switch can be set to the maintenance position;

[0016] Mode 3, accident ventilation mode: When the on-site gas detector alarms, the alarm system will lead the interlock start signal to the main electrical box through a set of switch dry contacts. The interlock contacts of the gas concentration automatic alarm contacts will be connected, the relay will be energized, the contactor will be energized and closed, and the forced start phase line will be energized. At this time, the exhaust fan will be energized and run regardless of whether the rotary button of the explosion-proof switch is in the open position or in the standby position; if the rotary button of the explosion-proof switch is in the maintenance position at this time, the fan will not start automatically, meeting the safety maintenance requirements.

[0017] Mode 4, manual emergency start mode: When on-site personnel discover an emergency and need to quickly start all exhaust fans for accident ventilation and evacuate as soon as possible, the staff needs to press the emergency start switch on the main electrical box on the facade of the hazardous chemicals warehouse. The emergency start switch contacts are closed, the relay is energized, the contactor is energized and closed, and the forced-start phase line is energized; at this time, whether the rotary button of the explosion-proof switch is in the open position or in the standby position, the fan is energized and runs; that is, it meets the requirements that the fan continues to run in the open position in the event of an accident and is forced to start when in the standby position; if at this time, the rotary button of the explosion-proof switch is in the maintenance position, the fan will not start automatically, meeting the safety maintenance requirements.

[0018] Beneficial effects

[0019] 1. Compared with traditional construction solutions, this invention reduces the amount of cables (copper usage), piping, the number of on-site switches, the size of explosion-proof distribution boxes, the number of circuit breakers and contactors, and the construction period. Preliminary estimates suggest that the construction cost of this invention is only about one-third of that of traditional construction solutions. Furthermore, inspection and maintenance during use are more convenient and quick.

[0020] 2. The utility model uses only one interlocking contact to start all emergency fans in the event of an accident, which has a simpler structure and more reliable operation.

[0021] 3. This new design replaces the traditional multiple, dispersed outdoor emergency start buttons with a single, self-locking emergency start button. This reduces the time required to start the emergency fan, saving valuable time for rapid evacuation. This invention reduces evacuation time to just one-fifth of traditional emergency evacuation time. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 This is a schematic diagram of the structure of the utility model Figure 1 ;

[0024] Figure 2 yes Figure 1 Transfer switch closure table in structure mode;

[0025] Figure 3 yes Figure 1 Switch layout diagram in structural mode;

[0026] Figure 4 yes Figure 1 Application floor plan in structural mode;

[0027] Figure 5 This is a schematic diagram of the structure of the utility model Figure 2 ;

[0028] Figure 6 yes Figure 5 Transfer switch closure table in structure mode;

[0029] Figure 7 yes Figure 5 Switch layout diagram in structural mode; DETAILED DESCRIPTION

[0030] 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. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0031] The utility model discloses a Figures 1 to 7 The hazardous chemicals warehouse accident ventilation control system and method shown in the figure mainly includes three parts: main electrical box, explosion-proof junction box, and explosion-proof transfer switch.

[0032] The main electrical box is the main power distribution hub for the system. It is wall-mounted outdoors and features a flameproof enclosure. The incoming cables utilize a three-phase, four-wire, five-core cable consisting of L1 through L3 + N + PE. The PE cable is re-grounded after entering the box. The box primarily includes: an isolating switch for safe isolation during maintenance; a motor circuit breaker for conventional protection against short circuits, overloads, and grounding; a self-locking emergency start switch for rapid activation of all emergency ventilation systems in an emergency. This switch requires manual reset; a KA relay that closes the KM contactor upon pressing the emergency start button or triggering the gas concentration alarm interlock signal; FU fuses for protecting the system's secondary circuit; and outgoing cables and piping, along with other equipment such as circuit breakers for lighting fixtures. The number of inlet and outlet ports is determined by requirement; G2" inlet ports and G1 1 / 2" outlet ports are recommended.

[0033] Explosion-proof junction boxes are primarily used for T-connected cables. They feature an internal terminal block and a double-grounded PE terminal. They feature a flameproof construction, three outlets, and a G1 1 / 2" interface.

[0034] The explosion-proof switch is located at the indoor exit of the corresponding fan service area. A multi-function transfer switch is installed to switch between the fan on, maintenance, and standby modes. The PE terminal has a double-grounded explosion-proof structure, a two-wire outlet, and a G1 1 / 2" interface.

[0035] The total power of a single series circuit in this utility model shall not exceed 3kW. If the total fan power exceeds 3kW, multiple wiring paths should be drawn from the main electrical box. The explosion-proof type of all electrical equipment should be determined by the environment in which it is used and the materials stored.

[0036] Normally, only one of the main and standby fans is in manual operation mode for warehouse ventilation, and the other is in standby operation mode. When a leakage alarm occurs, both the main and standby fans are put into operation. In addition, an emergency start button with a self-locking function is set on the outdoor explosion-proof main electrical box to quickly start the accident ventilation system of the entire hazardous chemicals warehouse. The construction cost of this invention is only about 1 / 3 of the cost of traditional construction solutions. The personnel evacuation time of this invention is only 1 / 5 of the traditional accident evacuation time. There are significant improvements in both economy and safety. The utility model has two control schemes. Scheme 1 is to set an independent knob control box for each fan; Scheme 2 is that the fans in the main and standby systems share a knob control box.

[0037] The system has the following operating modes when used for ventilation:

[0038] 1. Normal Ventilation Mode: During normal ventilation, the main electrical box circuit breaker is closed, the normal phase line L (including phases L1-L3) is energized, and the KM contactor is inoperative. Therefore, the forced-start phase line L' (including phases L'1-L'3) is de-energized. When the on-site explosion-proof switch knob is in the "Normal Open" position, the fan draws power from the normal phase line L (see "Transfer Switch Closure Table 1") and operates. When the on-site explosion-proof switch knob is in the "Normal Closed" position, the forced-start phase line L' is de-energized, and the fan stops.

[0039] 2. Maintenance / Emergency Stop Mode: When the on-site explosion-proof switch selector is in the "Maintenance / Emergency Stop" position, the fan cannot draw power from either the normal phase line L or the forced-start phase line L' (see "Switch Closure Table 1"). Used in conjunction with the maintenance position padlock, this prevents the fan from being accidentally energized, allowing reliable on-site maintenance of the corresponding motor. This position also serves as an emergency stop. If a motor malfunction or other on-site situation requires urgent power interruption, the switch can be set to the "Maintenance / Emergency Stop" position, using the same principle as above.

[0040] 3. Accident ventilation mode: When the on-site gas detector alarms, the alarm system will lead the interlock start signal to the main electrical box through a set of switch dry contacts. Figure 1In the main electrical box diagram, an interlock signal to start the fan is given. The interlock contact is turned on, the KA relay is energized, the KA contact is turned on, the KM contactor is energized and closed, and the forced-start phase line is energized. At this time, whether the rotary button of the explosion-proof switch is in the "normal open position" or the "normal closed position", the fan is energized and running. This meets the requirements that the fan will continue to run when it is in the "normal open position" and be forced to start when it is in the "normal closed position" in the event of an accident. If the rotary button of the explosion-proof switch is in the "maintenance" position at this time, the fan will not automatically start, meeting the safety maintenance requirements.

[0041] 4. Manual emergency start mode: When on-site personnel discover an emergency and need to quickly start all fans for emergency ventilation and evacuate as soon as possible, they need to press the "box surface self-locking emergency switch" located on the main electrical box on the facade of the hazardous chemicals warehouse (see "Fan control wiring"). Figure 1 At this point, the contacts of the "self-locking emergency switch on the box surface" close, the KA relay energizes, the KA contacts conduct, the KM contactor is energized and closed, and the forced-start phase line is energized. At this point, the fan is energized and running regardless of whether the rotary button of the explosion-proof switch is in the "normal open position" or the "normal closed position." This meets the requirements that the fan will continue to run in the "normal open position" and be forced to start in the "normal closed position" in the event of an accident. If the rotary button of the explosion-proof switch is in the "maintenance" position at this time, the fan will not automatically start, meeting the safety maintenance requirements. The combination of the emergency start button on the outdoor main electrical box and the button inside the warehouse jointly meets the specification requirement that fan starting devices be installed both indoors and outdoors.

[0042] Although an embodiment of the present invention has been shown and described, this specific embodiment is merely an explanation of the present invention and is not a limitation of the invention. The specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. After reading this specification, those skilled in the art may make modifications, substitutions and variations to the embodiment without creative contribution as needed without departing from the principles and purpose of the present invention. However, as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A small hazardous chemicals warehouse accident ventilation control system, including a main electrical box and an explosion-proof transfer switch; characterized in that: The main electrical box is provided with a gas concentration automatic alarm contact, an emergency start switch, a relay and a contactor. The relay is used to link the contactor to close after the emergency start switch is pressed or the gas concentration automatic alarm contact is triggered; the contactor is connected to the forced phase line; the explosion-proof conversion switch is installed on the main electrical box surface of the corresponding fan service storage area. The explosion-proof conversion switch is a multifunctional conversion switch, which is provided with an open position, a maintenance position and a standby position, and can realize the conversion of the fan between the three modes of opening, maintenance and standby. The maintenance position has an emergency stop function for the fan, and the line of the standby position is connected to the forced phase line.

2. A small-scale hazardous chemicals warehouse accident ventilation control system according to claim 1, characterized in that: The control system further comprises an explosion-proof wire box, in which a terminal block is provided. The fan circuit is T-connected with the corresponding normal phase line, forced start phase line and protection line in the explosion-proof wire box.

3. A small-scale hazardous chemicals warehouse accident ventilation control system according to claim 1, characterized in that: The emergency start switch is a box surface self-locking switch that needs to be manually reset.

4. A small-scale hazardous chemicals warehouse accident ventilation control system according to claim 1, characterized in that: The main electrical box is wall-mounted and installed outdoors, and the shell of the main electrical box adopts an explosion-proof structure.

5. A small-scale hazardous chemicals warehouse accident ventilation control system according to claim 1, characterized in that: The main electrical box is also provided with a circuit breaker and a fuse for the exhaust fan.

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