An outboard mounted cockpit safety door with modular overpressure mechanism and method

Abstract

The application discloses an out-of-cabin mounted cabin safety valve with a modular excess pressure mechanism and a method. The cabin safety valve comprises a shell (1), a diaphragm (2) arranged in the inner cavity of the shell (1), and a knife-edge valve (3) arranged on the bottom surface of the diaphragm (2). The upper surface of the diaphragm (2) and the shell (1) form a B cavity, the inner side of the knife-edge valve (3) and the shell (1) form an A cavity, and the outer side of the knife-edge valve (3), the bottom surface of the diaphragm (2) and the shell (1) form an atmosphere cavity (4) which is connected with the atmosphere. The A cavity and the B cavity are connected through a hollow valve rod (5). The B cavity is connected with an excess pressure mechanism. The cabin safety valve solves the problems of poor control precision, difficult product debugging and easy fluctuation of excess pressure value under high-altitude conditions.

Description

Technical Field

[0001] This invention belongs to the field of aircraft cabin pressure regulator technology, specifically relating to an externally mounted cabin safety valve with a modular overpressure mechanism and its method. Background Technology

[0002] Pneumatic cockpit safety valves open or close by sensing the pressure difference between atmospheric pressure and cabin pressure, ensuring that the residual pressure in the aircraft cabin does not exceed the structural safety pressure.

[0003] Based on the installation method of pneumatic cockpit safety doors on aircraft, they can be divided into two types: in-cabin safety doors and external cockpit safety doors. For the structure of in-cabin safety doors, see [link to relevant documentation]. Figure 1 The principle is as follows: The overpressure control mechanism of the safety valve senses the cabin pressure and atmospheric static pressure, which are isolated by a diaphragm assembly. The pressure regulating spring is in a compressed state, and the preload acts on the diaphragm assembly. When the pressure difference between the inside and outside of the cabin reaches a specified range, the diaphragm assembly moves to the right against the spring preload under the action of the pressure difference, causing the valve in the overpressure control mechanism to open. Air in chamber A is discharged into the atmosphere, reducing the pressure in chamber A. The valve opens under the action of the pressure difference, allowing air inside the cabin to be discharged into the atmosphere, reducing the cabin pressure. When negative pressure occurs in the cabin, the negative pressure diaphragm rises under the action of the pressure difference, causing the valve to open and allowing outside air to flow into the cabin, increasing the cabin pressure and eliminating the negative pressure. Compared to cabin safety valves installed inside the cabin, cabin safety valves installed outside the cabin have the advantages of smaller size, lighter weight, saving onboard space, and avoiding incorrect pipe installation (no need for pipe connection to the aircraft) (see [link]). Figure 2 The safety valve mainly consists of an inner diaphragm, an outer diaphragm (both are the same part), a main spring, a valve, a housing, and a cover. The cover of the cockpit safety valve is made of PEEK, and it, along with the outer and inner diaphragms, forms control chamber B. Inside chamber B is a spring, and a rod-shaped valve rests on a valve seat connected to the diaphragm, forming the adjustment mechanism. The rod-shaped valve is a hollow rod, with a through-hole in its core connecting chambers A and B. The pressure in chamber B is the cabin pressure P. C P C Increasing the gap between the lever-shaped valve and the valve seat allows air in chamber B to flow into chamber D, reducing pressure. This pressure then pushes open the valve, expelling air from the cabin and achieving depressurization. However, external installation presents challenges such as poor accuracy in controlling residual pressure, difficulties in product debugging, and fluctuations in residual pressure values ​​at high altitudes. Summary of the Invention

[0004] The purpose of this invention is to provide an externally mounted cockpit safety valve with a modular overpressure mechanism and a method thereof. This invention solves the problems of poor control accuracy, difficult product debugging, and easy fluctuation of overpressure values ​​under high-altitude conditions in externally mounted cockpit safety valves.

[0005] The technical solution of the present invention is: an externally mounted cabin safety valve with a modular overpressure mechanism, comprising a shell, a diaphragm disposed in the inner cavity of the shell, and a knife-edge valve on the bottom surface of the diaphragm; the upper surface of the diaphragm and the shell form cavity B, the inner side of the knife-edge valve and the shell form cavity A, and the outer side of the knife-edge valve, the bottom surface of the diaphragm and the shell form an atmospheric cavity communicating with the atmosphere; cavities A and B are connected by a hollow valve rod; cavity B is connected to the overpressure mechanism.

[0006] In the aforementioned externally mounted cockpit safety valve with a modular overpressure mechanism, the valve rod head passes through the top of the knife-edge valve and is fixed to the knife-edge valve, and the valve rod body is slidably connected to the cross rib fixed to the side wall of cavity A.

[0007] In the aforementioned externally mounted cabin safety valve with a modular overpressure mechanism, the overpressure mechanism includes an overpressure cover fixed to the outer wall of the shell. The inner cavity of the overpressure cover is divided into a valve cavity and a static pressure cavity by a diaphragm assembly. The valve cavity is connected to cavity B. The valve cavity is provided with a vent valve nozzle that communicates with the atmosphere. In the initial state, the vent valve nozzle is closed by the diaphragm assembly.

[0008] In the aforementioned externally mounted cockpit safety valve with a modular residual pressure mechanism, the static pressure chamber is also equipped with a spring I for assisting the diaphragm assembly in sealing the vent valve nozzle.

[0009] In the aforementioned externally mounted cockpit safety valve with a modular residual pressure mechanism, one end of the spring I abuts against the diaphragm assembly, and the other end abuts against the spring seat. The spring seat is connected to the pressure adjusting screw, and the pressure adjusting screw is connected to the residual pressure cover.

[0010] In the aforementioned externally mounted cockpit safety valve with a modular residual pressure mechanism, a filter screen is provided on the vent of the vent valve nozzle.

[0011] In the aforementioned externally mounted cockpit safety valve with a modular overpressure mechanism, a spring II is provided between the knife-edge valve and the top wall of the inner cavity of the shell.

[0012] A method for using an externally mounted cockpit safety valve as described above: Chamber A is connected to the cockpit. When the pressure difference between the inside and outside of the cockpit reaches a preset range, the pressure in Chamber B is transmitted to the pressure relief mechanism, which opens the pressure relief mechanism, allowing Chamber B to connect with the atmosphere. This allows the air inside the cockpit to be discharged into the atmosphere sequentially through Chamber A, the valve lever, Chamber B, and the pressure relief mechanism, thereby reducing the cockpit pressure.

[0013] In the aforementioned method of using the externally mounted cockpit safety valve, the overpressure mechanism opens as follows: when the pressure difference between the inside and outside of the cockpit reaches a preset range, the pressure in chamber B is transmitted to the valve cavity, pushing the diaphragm assembly away from the vent valve nozzle, thus connecting the valve cavity with the atmosphere.

[0014] In the aforementioned method of using the externally mounted cockpit safety valve, when negative pressure occurs in the cockpit, chamber B is in a negative pressure state. The atmospheric pressure in the atmospheric chamber pushes the diaphragm to open the knife-edge valve, thereby connecting chamber A with the atmospheric chamber. Outside air flows into chamber A through the atmospheric chamber, increasing the cabin pressure and eliminating the negative pressure.

[0015] The advantages of this invention are: this invention integrates the original control mechanism (such as...) Figure 2 (As shown) is changed to a residual pressure control mechanism, and in a mature residual pressure mechanism (such as...) Figure 1 Based on the above, a further optimization was carried out, and an externally mounted cabin safety door with a residual pressure structure (as shown) was designed. Figure 3 As shown in the figure, it effectively solves the problems of poor control accuracy of cabin safety valves installed outside the cabin, difficulty in product debugging, and easy fluctuation of residual pressure values ​​under high-altitude conditions.

[0016] Compared to existing external cabin safety doors (such as...) Figure 1 As shown, this invention adds a pressure control mechanism with higher precision to more accurately adjust the cabin pressure, solving the problem of easy fluctuation under high-altitude conditions.

[0017] This invention employs a sealing method between the nozzle of the height protection mechanism in the pressure regulator and the vulcanizing diaphragm assembly, making the current residual pressure mechanism simpler in structure, smaller in size, and lighter in weight compared to mature residual pressure mechanisms.

[0018] To ensure the centering of the valve stem, this invention employs cross-shaped ribs in its structure to restrict its alignment, preventing the valve stem from tilting during pressure adjustment.

[0019] This invention effectively solves the problem of the external cockpit safety valve, further ensuring the structural safety of the aircraft. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a traditional cabin safety hatch installed inside the cabin;

[0021] Figure 2 This is a structural diagram of a traditional externally mounted cockpit safety hatch;

[0022] Figure 3 This is a schematic diagram of the installation state of the present invention;

[0023] Figure 4 This is a schematic diagram of the structure of the present invention.

[0024] 1-Housing, 2-Diaphragm, 3-Knife-edge valve, 4-Atmospheric cavity, 5-Valve rod, 6-Cross rib, 7-Residual pressure cover, 8-Diaphragm assembly, 9-Valve cavity, 10-Static pressure cavity, 11-Ventilation valve nozzle, 12-Spring I, 13-Spring seat, 14-Pressure adjusting screw, 15-Filter screen, 16-Spring II. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0026] Example 1. An externally mounted cockpit safety hatch with a modular overpressure mechanism, configured as follows: Figure 1-4 As shown, the device includes a housing 1, with a diaphragm 2 inside the housing 1 and a knife-edge valve 3 on the bottom surface of the diaphragm 2. The upper surface of the diaphragm 2 and the housing 1 form a cavity B, the inner side of the knife-edge valve 3 and the housing 1 form a cavity A, and the outer side of the knife-edge valve 3, the bottom surface of the diaphragm 2 and the housing 1 form an atmospheric cavity 4 that communicates with the atmosphere. The A and B cavities are connected by a hollow valve rod 5. The B cavity is connected to a residual pressure mechanism.

[0027] In the aforementioned externally mounted cockpit safety valve with a modular overpressure mechanism, the head end of the valve rod 5 passes through the top of the knife-edge valve 3 and is fixed to the knife-edge valve 3, and the body of the valve rod 5 is slidably connected to the cross rib 6 fixed on the side wall of cavity A.

[0028] In the aforementioned externally mounted cabin safety valve with a modular overpressure mechanism, the overpressure mechanism includes an overpressure cover 7 fixed to the outer wall of the housing 1. The inner cavity of the overpressure cover 7 is divided into a valve cavity 9 and a static pressure cavity 10 by a diaphragm assembly 8. The valve cavity 9 is connected to cavity B. A vent valve 11 connected to the atmosphere is provided in the valve cavity 9. In the initial state, the vent valve 11 is closed by the diaphragm assembly 8.

[0029] In the aforementioned externally mounted cabin safety valve with a modular residual pressure mechanism, the static pressure chamber 10 is also equipped with a spring I 12 for assisting the diaphragm assembly 8 in sealing the vent valve nozzle 11.

[0030] In the aforementioned externally mounted cockpit safety valve with a modular residual pressure mechanism, one end of the spring I12 abuts against the diaphragm assembly 8, and the other end abuts against the spring seat 13. The spring seat 3 is connected to the pressure adjusting screw 14, and the pressure adjusting screw 14 is connected to the residual pressure cover 7.

[0031] In the aforementioned externally mounted cockpit safety valve with a modular residual pressure mechanism, a filter screen 15 is provided on the vent of the vent valve nozzle 11.

[0032] In the aforementioned externally mounted cockpit safety valve with a modular residual pressure mechanism, a spring II16 is provided between the knife-edge valve 3 and the top wall of the inner cavity of the housing 1.

[0033] In one method of using the aforementioned externally mounted cockpit safety valve, cavity A is connected to the cockpit. When the pressure difference between the inside and outside of the cockpit reaches a preset range, the pressure in cavity B is transmitted to the pressure relief mechanism, which opens the pressure relief mechanism, allowing cavity B to connect with the atmosphere. This allows the air inside the cockpit to be discharged into the atmosphere sequentially through cavity A, valve lever 5, cavity B, and pressure relief mechanism, thereby reducing the cockpit pressure.

[0034] The process of opening the pressure relief mechanism is as follows: when the pressure difference between the inside and outside of the cabin reaches the preset range, the pressure in chamber B is transmitted to the valve chamber 9, which pushes the diaphragm assembly 8 away from the ventilation valve nozzle 11, so that the valve chamber 9 is connected to the atmosphere.

[0035] When negative pressure occurs in the cabin, chamber B is in a negative pressure state. The atmospheric pressure of atmospheric chamber 4 pushes the diaphragm 2 to open the knife valve 3, thereby connecting chamber A with atmospheric chamber 4. Outside air flows into chamber A through atmospheric chamber 4, the cabin pressure increases, and the negative pressure is eliminated.

[0036] The main principle behind this invention's solution to the shortcomings of traditional external cabin safety valves is as follows: ① Traditional external cabin safety valves integrate the control and actuation mechanisms. When adjusting cabin pressure, the balance point between the control and actuation mechanisms is not easily stabilized, leading to unstable valve opening and closing and resulting in pressure fluctuations. This invention separates the control and actuation mechanisms, allowing them to operate independently without interference, thus stabilizing cabin pressure and reducing fluctuations. ② Compared to internal pressure control mechanisms, this invention achieves the same precision control but is lighter. As shown in Tables 1 and 2, the improved pressure control mechanism saves 0.1504 kg compared to the original (the difference between 0.1914 kg and 0.041 kg in Tables 1 and 2). The improved pressure control mechanism is only 21.5% of the weight of the original pressure control mechanism (this percentage is compared to the original internal pressure control mechanism, which weighs 0.1914 kg).

[0037] Table 1 Weight Distribution of the Improved Residual Pressure Mechanism

[0038]

[0039]

[0040] Table 2 Weight Distribution of Original Residual Pressure Control Mechanism

[0041]

[0042] In comparison, the present invention has significantly fewer standard parts, making installation more convenient.

[0043] In addition, the following situations may occur with traditional cabin external safety valves due to high-altitude fluctuations:

[0044] 1. During the commissioning of each batch of valves, 70% of the products will experience fluctuation problems, and 50% of the products will experience fluctuations exceeding 0.3 kPa.

[0045] 2. Of the 15 sets of traditional cockpit external safety doors installed before the improvement, only 4 sets passed the assembly test on the first attempt and did not require reassembly, with a first-time pass rate of only 26.67%.

[0046] The following are solutions to the high-altitude fluctuations of the traditional cabin external safety valve before improvement:

[0047] For products exhibiting fluctuation issues, the initial approach is to disassemble and reassemble the product, then conduct performance tests. If the results remain volatile, the process is repeated by replacing individual components such as the ball valve stem, valve seat, or knife valve. If these measures fail, the entire control mechanism is replaced, and the test is repeated. If the results still fluctuate, this process is repeated until the test results are satisfactory. While this approach can resolve the issue of fluctuating test results, it is cumbersome, unpredictable, and does not address the fundamental problem.

[0048] The following is a summary of the implementation status of the solutions:

[0049] 1. Products experiencing fluctuation issues will be disassembled and reassembled an average of 4 times, with each disassembly and reassembly taking 1 hour. Performance tests will be repeated 8 times, with each test lasting 2 hours. This leads to a sharp increase in product production costs and severely impacts product delivery schedules.

[0050] 2. Some products, after passing the debugging process, experienced fluctuations exceeding 0.3 kPa after being left for a period of time, leading to submission failures and causing serious consequences.

[0051] To solve the above-mentioned technical problems, the inventors conducted the following analysis of the traditional cockpit external safety valve structure design:

[0052] Analysis of the difficulties encountered in repeatedly assembling and debugging the aforementioned valves reveals that simply repeatedly disassembling and reassembling the product cannot effectively improve this situation. The inventors analyzed that the main reason for this shortcoming of traditional outboard cabin safety valves is that the control and actuator mechanisms are integrated. When adjusting cabin pressure, the balance point between the control and actuator mechanisms is not easily stabilized, leading to unstable valve opening and closing and thus pressure fluctuations. Based on this, this invention separates the control and actuator mechanisms, allowing them to operate independently without interference, thus stabilizing cabin residual pressure and reducing fluctuations. Based on this concept, the valve of this invention was designed. The safety valve of this invention has achieved significant results after the following experimental verification.

[0053] First trial

[0054]

[0055] Second test

[0056]

[0057] Third test

[0058]

[0059]

[0060] The three tests above show that the residual pressure fluctuations of the original type of cockpit external safety valve were 39.08-39.32=0.24, 38.95-39.47=0.52, and 38.16-39.34=0.18, respectively. When the residual pressure fluctuation (a characteristic of control accuracy) exceeded 0.3, it was accompanied by a loud snoring sound when the valve opened and closed, resulting in excessive noise and causing ear pressure symptoms for the occupants. However, using the cockpit safety valve structure of this invention, the residual pressure fluctuations were 39.12-39.18=0.06, 39.09-39.12=0.03, and 39.11-39.15=0.04, all of which did not exceed 0.1, effectively overcoming the above problems and demonstrating significant results.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. An externally mounted cockpit safety hatch with a modular overpressure mechanism, characterized in that, The device includes a housing, an inner cavity of which is provided with a diaphragm, and a knife-edge valve on the bottom surface of the diaphragm; the upper surface of the diaphragm and the housing form cavity B, the inner side of the knife-edge valve and the housing form cavity A, and the outer side of the knife-edge valve, the bottom surface of the diaphragm and the housing form an atmospheric cavity that communicates with the atmosphere; cavities A and B are connected by a hollow valve rod; cavity B is connected to a residual pressure mechanism. The valve rod head passes through the top of the knife-edge valve and is fixed to the knife-edge valve. The valve rod body is slidably connected to the cross rib fixed to the side wall of cavity A. The residual pressure mechanism includes a residual pressure cover fixed to the outer wall of the housing. The inner cavity of the residual pressure cover is divided into a valve cavity and a static pressure cavity by a diaphragm assembly. The valve cavity is connected to cavity B. The valve cavity is provided with a vent valve that communicates with the atmosphere. In the initial state, the vent valve is closed by the diaphragm assembly. The static pressure chamber is also equipped with spring I for assisting the diaphragm assembly in sealing the vent valve; One end of spring I rests against the diaphragm assembly, and the other end rests against the spring seat. The spring seat is connected to the pressure adjusting screw, and the pressure adjusting screw is connected to the pressure relief cover.

2. The externally mounted cockpit safety door with a modular overpressure mechanism according to claim 1, characterized in that, The vent of the vent valve is equipped with a filter screen.

3. The externally mounted cockpit safety door with a modular overpressure mechanism according to claim 1, characterized in that, A spring II is provided between the blade valve and the top wall of the inner cavity of the housing.

4. A method of using an externally mounted cockpit safety door as described in any one of claims 1-3, characterized in that, Chamber A is connected to the cabin. When the pressure difference between the inside and outside of the cabin reaches a preset range, the pressure in Chamber B is transmitted to the pressure relief mechanism, which opens the pressure relief mechanism, allowing Chamber B to connect with the atmosphere. This allows the air in the cabin to be discharged into the atmosphere in sequence through Chamber A, the valve lever, Chamber B, and the pressure relief mechanism, thus reducing the cabin pressure.

5. The method of using the externally mounted cockpit safety door according to claim 4, characterized in that, The process of opening the pressure relief mechanism is as follows: when the pressure difference between the inside and outside of the cabin reaches the preset range, the pressure in chamber B is transmitted to the valve chamber, pushing the diaphragm assembly away from the ventilation valve nozzle, so that the valve chamber is connected to the atmosphere.

6. The method of using the externally mounted cockpit safety door according to claim 4, characterized in that, When negative pressure occurs in the cabin, chamber B is under negative pressure. The atmospheric pressure in the atmospheric chamber pushes the diaphragm to open the knife valve, thereby connecting chamber A with the atmospheric chamber. Outside air flows into chamber A through the atmospheric chamber, increasing the cabin pressure and eliminating the negative pressure.

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