A secondary safety device for a device cooling water blowdown valve
Patent Information
- Application Number
- CN202522345868.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-05
- Publication Date
- 2026-11-03
- Estimated Expiration
- 2035-11-05
AI Technical Summary
In the existing technology, the cooling water drain valve control system is susceptible to the loss of control signals or damage to the PLC output module, which leads to continuous loss of cooling water, a sharp rise in equipment temperature, and unplanned downtime and equipment damage.
A secondary safety device for the equipment cooling water drain valve was designed. It adopts an independent redundant protection circuit consisting of an intermediate relay, a first time relay, and a second time relay. By delaying the closing of the main cooling water valve, it ensures that the cooling water supply can be cut off in time when the main control system fails.
It effectively prevents cooling water loss and equipment overheating caused by single-point failure, ensures production continuity and equipment safety, reduces economic losses, and is low-cost, responsive, stable and reliable.
Smart Images
Figure CN224935433U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of industrial fluid control and equipment safety protection, and in particular to a secondary safety device for a cooling water drain valve. Specifically, it is a secondary safety device installed on the control system of the cooling water drain valve to provide redundant protection in the event of a failure of the main control system. Background Technology
[0002] In continuous production processes such as electrolytic copper foil production, core equipment like the foil-making machine requires continuous and stable cooling water for temperature reduction. Cooling water drain valves are typically driven by electric actuators and open / close under commands from a central control system. Existing technologies generally rely on a single control loop, i.e., a single-point control mode of control system – electric valve.
[0003] The common feature of these solutions is that once the control signal is lost, the PLC output module is damaged, or the electric valve itself is stuck, the valve will be unable to execute the closing command, resulting in continuous loss of cooling water, a sharp rise in equipment temperature, and ultimately causing large-scale unplanned shutdowns or even equipment damage, leading to huge economic losses. Utility Model Content
[0004] The main objective of this invention is to solve the technical problems in the prior art where control signals are easily lost and PLC output modules are easily damaged, leading to continuous cooling water loss and a sharp rise in equipment temperature. A secondary safety device for a cooling water drain valve is provided, comprising: a power module, an intermediate relay, a first time relay, a second time relay, and a main cooling water valve. The power supply module supplies power to the intermediate relay, the first time relay, the second time relay, and the main cooling water valve; The intermediate relay receives external signals and is activated when powered on. When the intermediate relay is energized, it controls the opening of the first time relay and the second time relay; The first time relay is used to control the intermediate relay to close after a delay; The second time relay is used to control the main cooling water valve to close after a delay.
[0005] The intermediate relay includes a normally open contact, which forms a self-locking circuit to ensure that it remains engaged even if the external signal disappears briefly.
[0006] The intermediate relay includes a first control contact and a second control contact. When the intermediate relay is energized, the first control contact causes the power module to supply power to the first time relay; the second control contact causes the power module to supply power to the second time relay.
[0007] The first time relay shuts off the power supply to the intermediate relay through the first time relay delayed closing contact.
[0008] The second time relay closes the main cooling water valve through its delayed closing contact.
[0009] The delay time of the second time relay is greater than the delay time of the first time relay.
[0010] The secondary safety device also includes a status indicator light, which is used to indicate whether the device is in a normal, faulty, or fault-locked state.
[0011] The secondary safety device also includes a manual reset button for resetting the secondary safety device.
[0012] The secondary safety device is implemented using a small programmable logic controller or a microcontroller as its core.
[0013] The second time relay determines whether to close the main cooling water valve based on the second time relay delayed closing contact, the low cooling water flow alarm signal, and the equipment over-temperature signal.
[0014] This utility model has the following beneficial effects: This invention provides a second layer of protection independent of the main control system, effectively preventing cooling water loss and equipment overheating accidents caused by single-point failures, and ensuring production continuity and equipment safety.
[0015] This invention achieves high-value security functions at extremely low hardware costs, saving huge economic losses caused by downtime and production accidents, and resulting in a high return on investment.
[0016] This invention is a pure hardware circuit logic, which is not affected by software crashes, viruses, or other risks, and has a rapid response and stable operation.
[0017] The circuit structure of this utility model is standard, the wiring is simple, and ordinary electricians can complete the installation and daily maintenance without complicated programming and debugging. Attached Figure Description
[0018] Figure 1 Circuit diagram of the secondary safety device for the equipment cooling water drain valve provided in this embodiment of the utility model.
[0019] The attached figures are labeled as follows: Power module 1, intermediate relay 2, first time relay 3, second time relay 4, cooling water main valve 5, intermediate relay normally open contact 21, intermediate relay first control contact 22, intermediate relay second control contact 23, first time relay delayed closing contact 31, second time relay delayed closing contact 41. Detailed Implementation
[0020] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" or "having" and any variations thereof are intended to cover a non-exclusive inclusion; for example, a system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such products or devices.
[0021] This invention aims to overcome the shortcomings of existing technologies and provide a simple, low-cost, and reliable secondary safety device. Its core lies in employing purely electrical hard-wired logic to construct an emergency shutdown circuit independent of the main control system. The device mainly consists of an intermediate relay, two time relays, and matching power and signal interfaces. When the device detects the closing signal of the cooling water drain valve, it triggers an independent timing judgment process: if the drain valve fails to close successfully within the normal time set by the main system, the device will forcibly intervene, outputting a high-priority shutdown signal to the main cooling water valve, forcing it to close, thereby protecting the equipment and cooling water resources.
[0022] For ease of understanding, the specific process of the embodiments of this utility model is described below. Please refer to [link / reference]. Figure 1 The first embodiment of the secondary safety device for the equipment cooling water drain valve in this utility model includes: The system includes a power module, intermediate relays, a first time relay, a second time relay, and a main cooling water valve. The power module supplies power to the intermediate relays, the first time relay, the second time relay, and the main cooling water valve. The intermediate relays receive external signals and energize upon receiving power. Energized intermediate relays control the opening of the first and second time relays. The first time relay controls the delayed closing of the intermediate relays; the second time relay controls the delayed closing of the main cooling water valve. Each intermediate relay includes a normally open contact that forms a self-locking path, ensuring that the intermediate relay remains energized even if the external signal is briefly lost. Each intermediate relay includes a first control contact and a second control contact. When an intermediate relay is energized, the first control contact powers the first time relay; the second control contact powers the second time relay. The first time relay shuts off power to the intermediate relay via its delayed closing contact. The second time relay closes the main cooling water valve via its delayed closing contact. The delay time of the second time relay is longer than that of the first time relay. The secondary safety device also includes a status indicator light, which is used to indicate whether the device is in a normal, faulty, or fault-locked state.
[0023] In a preferred embodiment, the secondary safety device also includes a manual reset button for resetting the secondary safety device.
[0024] The manual reset button provides users with an interface for active intervention. After the device is triggered and enters the self-holding state, even if the entire logic process has not yet been completed (i.e., the first-time relay has not yet reset), maintenance personnel can press this button to directly cut off the self-locking circuit of the intermediate relay, forcing the device to reset. This enhances the controllability of the device and facilitates rapid system recovery during commissioning, testing, or emergencies.
[0025] As a preferred implementation, the secondary safety device is implemented using a small programmable logic controller or a microcontroller as its core.
[0026] The intermediate relay, the first time relay, and the second time relay are replaced by a small programmable logic controller (PLC) or microcontroller and its peripheral circuitry. The PLC or microcontroller is programmed to execute the following logic: a. Receive the cooling water drain valve closing signal; b. Initiate a first delay judgment program; c. If the closing signal is withdrawn within the first delay time, automatically reset; d. If the closing signal still exists after the first delay time, output a forced closing signal to the cooling water main valve through the control output interface; e. After outputting the forced closing signal, initiate a second delay reset program, and reset the entire device after the second delay time.
[0027] When using a PLC or microcontroller, the device's logic functions are implemented through a program, and its core decision-making process (decision-execution-reset) is consistent with the hardware solution. The advantage of this implementation is its high flexibility; delay parameters and logical relationships can be easily adjusted by modifying the program without altering the hardware wiring. Furthermore, it allows for easy functional expansion, such as adding detailed status indicators, data communication with upper-level control systems, and recording fault events. The disadvantage is a relatively higher cost compared to a pure hardware solution, but it offers greater integration and scalability.
[0028] In a preferred embodiment, the second time relay determines whether to close the main cooling water valve based on the second time relay delayed closing contact, the low cooling water flow alarm signal, and the equipment over-temperature signal.
[0029] This solution significantly expands the protection scope and application scenarios of secondary safety devices. It no longer relies solely on the failure mode of a shutdown command not being executed, but instead adds direct monitoring of the actual operating status of the system.
[0030] Working principle: The delayed action signal from KT2, the low flow alarm signal, and the over-temperature alarm signal are jointly controlled by an OR logic to control the final output (S2). As long as any one of these conditions is met, the device will immediately execute the protective action of closing the main cooling water valve.
[0031] Even if the main control system does not issue a command to close the drain valve, if the system cooling water flow is too low due to reasons such as pipe rupture or water pump failure, this signal will directly trigger the protection to prevent the equipment from overheating.
[0032] Similarly, regardless of the upstream cause, the device will activate directly as long as the core temperature of the equipment exceeds the safety threshold.
[0033] This upgrades the secondary safety device from a single instruction execution failure protector to a multi-functional, end-effect-based comprehensive security gateway, achieving deeper redundancy protection and enabling it to cope with a wider range of possible failure scenarios.
[0034] In this invention, an interlocking circuit formed by the intermediate relay coil and the normally closed contact of timer No. 1 ensures that once the device is triggered, it enters a stable self-holding state until the entire logic process is completed, greatly improving anti-interference capability and operational reliability. This ensures that the secondary safety device can reliably start and remain in standby mode after receiving the initial shutdown signal, avoiding failure due to signal jitter or momentary interruptions.
[0035] In this invention, timer number 2 is set with a reasonable delay (e.g., 5 seconds) as a time window to determine whether the main system is operating normally. If the main system successfully closes the valve within 5 seconds, the signal is reset, and the device does not operate; if it fails to close after 5 seconds, it is determined to be a fault, and the device shuts down automatically. Timer number 1, after timer number 2 activates, is responsible for releasing the self-locking mechanism and resetting the entire device to prepare for the next operation. This "judgment-execution-reset" logical flow is ingeniously conceived and precisely executed.
[0036] This invention abandons expensive PLCs or dedicated controllers, and instead uses a combination of intermediate relays and time relays, which are extremely common and inexpensive in the industrial field, to achieve the same safety functions. This makes the device easy to produce, promote, and retrofit into existing equipment, offering extremely high cost-effectiveness.
[0037] This invention provides a second layer of protection independent of the main control system, effectively preventing cooling water loss and equipment overheating accidents caused by single-point failures, ensuring production continuity and equipment safety. This invention achieves high-value safety functions at extremely low hardware costs, saving significant economic losses caused by downtime and production accidents, resulting in a high return on investment. This invention uses pure hardware circuit logic, is unaffected by software crashes, viruses, or other risks, and offers rapid response and stable operation. The circuit structure is standard, wiring is simple, and installation and routine maintenance can be completed by ordinary electricians without complex programming or debugging.
[0038] Workflow: 1. Trigger: When the main control system sends the "Close Cooling Water Drain Valve" signal S1, signal S1 is simultaneously sent to the drain valve itself and the intermediate relay KA. The S1 signal energizes the coil of the intermediate relay KA.
[0039] 2. Self-locking and starting: After the intermediate relay KA is energized, its normally open contact closes, forming a self-locking path to ensure that the intermediate relay KA remains energized even if the S1 signal disappears briefly. At the same time, another set of contacts of the intermediate relay KA is closed, supplying power to the first time relay SJ1 and the second time relay SJ2, and the two timers begin counting.
[0040] 3. Delay Judgment: The delay time of the second time relay SJ2 is set to 5 seconds. Within these 5 seconds, if the main control system is working normally, the drain valve will close, and the system pressure or flow sensor will return a normal signal. The main control system will then reset the initial closing signal, causing S1 to disconnect, which in turn de-energizes the intermediate relay KA, and the device will reset.
[0041] 4. Fault Execution: If the main system fails to close the drain valve due to a fault after 5 seconds and the S1 signal still exists, the second time relay SJ2 will arrive after a delay, and its delayed closing contact will close, sending a strong closing signal to the cooling water main valve to force the main valve to close.
[0042] 5. Device Reset: Simultaneously with the activation of the second time relay SJ2, its signal also triggers the first time relay SJ1 to begin a delay (e.g., 90 seconds). After the delay of the first time relay SJ1, its normally closed contact opens, cutting off the self-locking circuit of the intermediate relay KA, causing the intermediate relay KA to lose power. The entire device (including the first time relay SJ1 and the second time relay SJ2) resets, awaiting the next trigger. This design prevents the device from being continuously energized.
[0043] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.
Claims
1. A secondary safety device for a cooling water drain valve, characterized in that, The secondary safety device includes: a power module, an intermediate relay, a first time relay, a second time relay, and a cooling water main valve; The power supply module supplies power to the intermediate relay, the first time relay, the second time relay, and the main cooling water valve; The intermediate relay receives external signals and is activated when powered on. When the intermediate relay is energized, it controls the opening of the first time relay and the second time relay; The first time relay is used to control the intermediate relay to close after a delay; The second time relay is used to control the main cooling water valve to close after a delay.
2. The secondary safety device for a cooling water drain valve according to claim 1, characterized in that, The intermediate relay includes a normally open contact, which forms a self-locking path to ensure that it remains engaged even if the external signal disappears briefly.
3. The secondary safety device for a cooling water drain valve according to claim 1, characterized in that, The intermediate relay includes a first control contact and a second control contact. When the intermediate relay is energized, the first control contact causes the power module to supply power to the first time relay; the second control contact causes the power module to supply power to the second time relay.
4. The secondary safety device for a cooling water drain valve according to claim 3, characterized in that, The first time relay shuts off the power supply to the intermediate relay through the first time relay delayed closing contact.
5. A secondary safety device for a cooling water drain valve according to claim 4, characterized in that, The second time relay closes the main cooling water valve through its delayed closing contact.
6. A secondary safety device for a cooling water drain valve according to claim 5, characterized in that, The first time relay and the second time relay work simultaneously, and the delay time of the second time relay is greater than the delay time of the first time relay.
7. A secondary safety device for a cooling water drain valve according to claim 1, characterized in that, The secondary safety device also includes a status indicator light, which is used to indicate whether the device is in a normal, faulty, or fault-locked state.
8. A secondary safety device for a cooling water drain valve according to claim 1, characterized in that, The secondary safety device also includes a manual reset button for resetting the secondary safety device.
9. A secondary safety device for a cooling water drain valve according to claim 1, characterized in that, The secondary safety device is implemented using a small programmable logic controller or a microcontroller.
10. A secondary safety device for a cooling water drain valve according to claim 1, characterized in that, The second time relay determines whether to close the main cooling water valve based on the delayed closing contact of the second time relay, the low cooling water flow alarm signal, and the equipment over-temperature signal.