Delay ignition device and solid rocket engine

Abstract

The invention relates to the technical field of solid rocket engines, in particular to a delayed ignition device and a solid rocket engine. Comprising an ignition powder box used for igniting a main-stage engine charge, a delay tube used for delaying ignition of the ignition powder box, a fixing support used for fixing the delay tube and a fire transfer tube used for transferring high-temperature fuel gas generated when a transmitting-stage engine works to the delay tube, and the input end of the delay tube is connected with the output end of the fire transfer tube. And the output end of the delay tube acts on the ignition powder box. According to the delay ignition device, high-temperature fuel gas generated when the transmitting-stage engine works is transmitted to the delay tube through the fire transmission tube, after the delay tube receives the high-temperature fuel gas transmitted by the fire transmission tube, energy is reliably output at the output end in a delayed mode, and an ignition powder box of the main-stage engine is ignited, so that autonomous and reliable delay ignition of the main-stage engine is achieved; an ignition signal input electrical interface, a special ignition module and a special security mechanism module do not need to be designed for the main-stage engine, so that the whole-missile structure is simpler and more compact, and the length of a control cabin is effectively shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of solid rocket engines, and particularly relates to a delay ignition device and a solid rocket engine. Background Art

[0002] Due to its characteristics of simple maintenance and high working reliability, solid rocket engines are widely used as power devices for various types of tactical rockets, missiles, and artillery weapons. As the core component of the ignition system of a solid rocket engine, the reliability of the ignition device directly affects the ignition reliability of the engine, thereby affecting the working performance of the engine.

[0003] The conventional ignition method for a solid rocket engine is to give an ignition signal through an on-board computer or a firing control device. After the input end of the electric igniter is stimulated by a given current, the electric igniter sprays high-temperature gas and hot particles outward, thereby igniting the main charge of the engine, and thus completing the engine ignition work. This type of ignition method is usually used for the instantaneous ignition of a solid rocket engine.

[0004] When adopting the on-board computer control multi-stage engine controllable delay ignition scheme, the following conditions need to be met: a) It is necessary to design an electrical interface for independent ignition signal input of the multi-stage engine; b) It is necessary to design a multi-stage engine ignition module and an ignition safety and insurance module; c) It is necessary to design the ignition circuit of the multi-stage engine. Therefore, it is necessary to lay the missile wall cable and the cable routing cover on the outer wall of the missile.

[0005] Some models of solid rocket engines using the conventional main stage engine controllable delay ignition scheme have the following problems: a) Due to the need for the combustion chamber charge design, the ignition signal input line of the main stage engine is inconvenient to be led out from the front end of the engine, and the tail of the main stage engine is equipped with a rotating tail fin mechanism, so it cannot be led out from the tail; b) Due to the limited overall size of the missile, adding an additional ignition module and safety module requires an additional increase in the length of the missile body; c) Adding the missile wall cable and the cable cover will increase the aerodynamic drag.

[0006] Therefore, it is necessary to design a delay ignition device and a solid rocket engine to solve the above problems. Summary of the Invention

[0007] The purpose of the present invention is to provide a delay ignition device and a solid rocket engine, which can achieve autonomous and reliable delay ignition of the main stage engine, without the need to design an ignition signal input electrical interface, a dedicated ignition module, and a security mechanism module, effectively shortening the length of the control cabin and reducing the aerodynamic drag of the missile flight.

[0008] To achieve the above object, the technical solution of the present invention is a time-delay ignition device, which includes an ignition cartridge for igniting the main-stage engine charge, a delay tube for delaying the ignition of the ignition cartridge, a fixing bracket for fixing the delay tube, and a fire-transfer tube for transferring the high-temperature gas generated during the operation of the launch-stage engine to the delay tube. The input end of the delay tube is connected to the output end of the fire-transfer tube, and the output end of the delay tube acts on the ignition cartridge.

[0009] As one of the embodiments, the fixing bracket includes an inner ring part, an outer ring part, and an intermediate spoke part, and the inner ring part, the intermediate spoke part, and the outer ring part are sleeved on the delay tube in sequence from inside to outside.

[0010] As one of the embodiments, a plug is provided on one side of the fixing bracket at the output end of the delay tube for blocking the intermediate spoke part during ignition and releasing the blockage after ignition.

[0011] As one of the embodiments, the plug is made of an easily foamed molding material.

[0012] As one of the embodiments, the outer ring part and the intermediate spoke part are made of a non-metallic composite material resistant to erosion and ablation, and the inner ring part is made of a metal material.

[0013] As one of the embodiments, the input end of the delay tube and the output end of the fire-transfer tube are in clearance fit with a shaft hole, and at least one sealing ring is provided in the clearance between the delay tube and the fire-transfer tube.

[0014] As one of the embodiments, the inner diameter of the input end of the fire-transfer tube and the inner diameter of the output end of the fire-transfer tube are both larger than the inner diameter of the middle part of the fire-transfer tube.

[0015] As one of the embodiments, the delay tube includes a housing, and slow-burning powder is contained in the housing.

[0016] The present invention also provides a solid rocket engine, which includes a main-stage engine and a launch-stage engine. The main-stage engine includes a charge combustion chamber, a tail pipe, and a nozzle; it also includes the time-delay ignition device described in any one of the above, the fixing bracket is installed in the tail pipe, the ignition cartridge is installed in the charge combustion chamber, and the fire-transfer tube is arranged in the nozzle and the input end is connected to the launch-stage engine.

[0017] As one of the embodiments, the ratio of the ventilation area of the fixing bracket to the throat area of the nozzle is greater than 2:1.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The present invention transfers the high-temperature gas generated during the operation of the launch-stage engine to the delay tube through a flame transfer tube. After the delay tube receives the high-temperature gas transferred by the flame transfer tube, it delays the energy and reliably outputs it at the output end, and ignites the ignition cartridge of the main-stage engine, thereby achieving autonomous and reliable delayed ignition of the main-stage engine.

[0020] (2) The present invention fixes the delay tube in the tail tube of the main-stage engine through a fixing bracket. This fixing bracket can withstand the forward acting force of the high pressure generated during the operation of the launch-stage engine on the delay tube in the forward direction, ensuring no structural damage. At the same time, under the scouring of the high-temperature, high-pressure, and high-speed airflow generated during the operation of the main engine, no large or fragmented foreign objects are generated to cause blockage of the throat of the main-stage engine nozzle.

[0021] (3) The output end of the flame transfer tube of the present invention and the input end of the delay tube adopt an axial hole clearance fit, and at least one sealing ring is arranged in the clearance, which is convenient for the assembly and separation of the launch-stage engine and the main-stage engine, and at the same time ensures no air leakage during flame transfer.

[0022] (4) The main-stage engine of the present invention relies on the high-temperature and high-pressure gas generated by the operation of the launch-stage engine to achieve autonomous and reliable delayed ignition through a delayed ignition device. Therefore, the main-stage engine does not need to design an electrical interface for inputting ignition signals, nor does it need to add a special ignition module and security mechanism module and then control the ignition of the main engine through the on-board computer. And because there is no main-stage engine ignition module and ignition safety mechanism module in the control cabin, the overall structure of the entire missile can be made more compact, effectively shortening the length of the control cabin, and effectively solving the problem of limited total length of the entire missile.

[0023] (5) Since the main-stage engine of the present invention adopts autonomous and reliable delayed ignition and the igniter has no lead wire led out, it is not necessary to consider the routing and leading-out method of the igniter wire in the overall design of the solid rocket engine, nor is it necessary to consider the problem of pre-burying the ignition wire in the propellant combustion chamber. This greatly facilitates the production of the engine propellant and the overall assembly of the engine. And since there is no need to design a missile body cable on the missile, there is no missile body cable cover for the entire missile, which can reduce the protrusion outside the missile body, thereby reducing the aerodynamic drag of the missile during flight. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a schematic structural diagram of the delayed ignition device provided by the embodiment of the present invention.

[0026] Figure 2Schematic diagram of the structure of the flame transfer tube provided by the embodiment of the present invention;

[0027] Figure 3 Schematic diagram of the installation of the delay tube provided by the embodiment of the present invention in the fixed bracket;

[0028] Figure 4 Schematic diagram of the installation of the delay tube provided by the embodiment of the present invention in the fixed bracket;

[0029] In the figure: 31, ignition cartridge; 32, plug; 33, fixed bracket; 331, inner ring part; 332, intermediate spoke part; 333, outer ring part; 34, delay tube; 35, sealing ring; 36, flame transfer tube. Detailed implementation manners

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0032] The terms "first" and "second" are only used for descriptive purposes, and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features; in the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0033] As Figures 1 - 3 shown, this embodiment provides a delay ignition device, including an ignition cartridge 31 for igniting the ignition device of the main-stage engine, a delay tube 34 for delaying the ignition of the ignition cartridge 31, a fixed bracket 33 for fixing the delay tube 34, and a flame transfer tube for transferring the high-temperature gas generated during the operation of the launch-stage engine to the delay tube 34. The input end of the delay tube 34 is connected to the output end of the flame transfer tube 36, and the output end of the delay tube 34 acts on the ignition cartridge 31.

[0034] In this embodiment, the high-temperature combustion gas generated when the launch-stage engine is working is transferred to the delay tube 34 through the fire transfer tube 36. After receiving the high-temperature combustion gas transferred from the fire transfer tube 36, the delay tube 34 delays the energy to be reliably output at the output end, and ignites the ignition cartridge 31 of the main-stage engine, thereby realizing autonomous and reliable delayed ignition of the main-stage engine.

[0035] In some embodiments, the fixing bracket 33 includes an inner ring portion 331, an outer ring portion 333 and an intermediate spoke portion 332, and the inner ring portion 331, the intermediate spoke portion 332 and the outer ring portion 333 are sequentially sleeved on the extension tube 34 from the inside to the outside. Optimally, the inner ring portion 331, the outer ring portion 333 and the intermediate spoke portion 332 of the fixing bracket 33 are an integrated structure. Among them, the inner ring portion 331 provides an installation interface for the extension tube 3; the outer ring portion 333 provides a sleeve interface in the tail pipe of the main stage engine; the intermediate spoke portion 332 is used to connect the inner ring portion 331 and the outer ring portion 333, and at the same time serves as a gas channel reserved for the operation of the main stage engine.

[0036] Furthermore, the inner ring part 331 is threadedly connected to the extension tube 34. Specifically, an outer thread is provided on the outer wall of the extension tube 34 at a position corresponding to the inner ring part 331, and an inner thread is provided on the inner wall of the inner ring part 331. The outer thread and the inner thread are threadedly connected to ensure that the extension tube 34 is reliably connected to the fixing bracket 33.

[0037] Furthermore, the middle spoke part 332 includes a mounting ring and a plurality of spokes evenly arranged along the circumference of the mounting ring, and the spokes are integrally formed with the mounting ring. On the one hand, the middle spoke part 332 serves to connect the inner ring part 331 and the outer ring part 33, and on the other hand, the hollow area between the spokes can be used as a vent to facilitate the smooth discharge of high-temperature combustion gas generated after the ignition cartridge 31 is ignited. Figure 4 As shown, three spokes are connected to the mounting ring, and the three spokes are arranged at equal intervals along the circumference of the mounting ring.

[0038] In some embodiments, a plugging cover 32 is provided on one side of the fixing bracket 33 at the output end of the delay tube 34 for blocking the middle spoke portion 332 during ignition and unblocking after ignition. The hollow area of the middle spoke portion 332 is blocked by the plugging cover 32 to ensure that the necessary ignition critical pressure can be established when the main stage engine is ignited. Figure 1 As shown, the outer conical surface of the plugging cover 32 is matched with the inner conical surface of the fixed bracket 33, and silicone rubber is applied between the matching surfaces for bonding and sealing. The radial gap between the middle inner hole of the plugging cover 32 and the output end of the extension tube 34 is sealed by silicone rubber. At the same time, the bottom end face of the plugging cover 32 is fitted with one side of the middle spoke part 332 of the fixed bracket 33.

[0039] Furthermore, the plug cap 32 is made of an easily foamable molding material. The plug cap 32 in this embodiment is made of an easily foamable molding material and has a pressure-bearing capacity of 2.5 MPa to 6.0 MPa. It can not only withstand the pressure generated by the ignition pressure during the ignition of the main-stage engine, but also be burned off by the high-temperature gas generated after the main-stage engine starts to work, without hindering the high-temperature gas from discharging through the hollow area of the intermediate spoke portion 332. Among them, the easily foamable molding material can specifically be expandable polystyrene material, etc.

[0040] Furthermore, the outer ring portion 333 and the intermediate spoke portion 332 are made of a non-metallic composite material with anti-scouring and ablation resistance, and the inner ring portion 331 is made of a metal material. In this embodiment, the outer ring portion 333 and the intermediate spoke portion 332 are made of a non-metallic composite material with anti-scouring and ablation resistance, which can effectively resist the scouring of the high-temperature gas generated during the operation of the engine and ensure the stability and integrity of the structure; the inner ring portion 331 is made of a metal material and is reliably connected to the delay tube 34 by threads. Among them, the non-metallic composite material with anti-scouring and ablation resistance can specifically be carbon fiber / phenolic material, with a density ≥ 1.42 g / cm3, an oxygen-acetylene linear ablation rate ≤ 0.06 mm / s, and a thermal conductivity ≤ 0.65 W / (m·k); the metal material can specifically be stainless steel material, such as 12Cr18Ni9, etc.

[0041] In this embodiment, the outer ring portion 333 and the intermediate spoke portion 332 are integrally formed, and the inner ring portion 331 is embedded into the mounting ring of the intermediate spoke portion 332 by a molding method. Furthermore, two raised circular rings are provided on the outer wall of the inner ring portion 331, which is convenient for the metal inner ring portion 331 to be embedded into the non-metallic material, and is beneficial to the more firm and reliable molding of the metal inner ring portion 331 with the non-metallic outer ring portion 333 and the intermediate spoke portion 332.

[0042] In some embodiments, the input end of the delay tube 34 and the output end of the fire-transfer tube 36 are in an axial-hole clearance fit, and at least one sealing ring 35 is provided in the gap between the delay tube 34 and the fire-transfer tube 36. The launch-stage engine and the main-stage engine are separated when the missile exits the barrel. Since the output end of the fire-transfer tube 36 and the input end of the delay tube 34 are in an axial-hole clearance fit, the fire-transfer tube 36 on the launch-stage engine can be separated from the delay tube 34 on the main-stage engine simultaneously; and at least one sealing ring 35 is provided in the gap between the delay tube 34 and the fire-transfer tube 36 to ensure that there is no air leakage when the high-temperature and high-pressure gas generated by the launch-stage engine transfers fire, meeting the sealing requirement for the delayed fire transfer of the main-stage engine.

[0043] Preferably, two sealing grooves are arranged circumferentially on the outer wall of the delay tube 34, and O-ring seals 35 are installed in both sealing grooves. The O-ring seals 35 are hermetically connected to the outer wall of the delay tube 34 and the inner wall of the flame transfer tube 36, further improving the reliability of flame transfer.

[0044] In some embodiments, the inner diameter of the input end of the flame transfer tube 36 and the inner diameter of the output end of the flame transfer tube 36 are both larger than the inner diameter of the middle part of the flame transfer tube 36. The flame transfer tube 36 in this embodiment adopts a structural form with large openings at both ends and a small channel in the middle. The large opening at the input end is convenient for receiving the high-temperature gas generated during the operation of the launch stage engine. The small channel in the middle can increase the speed of the high-temperature gas and reduce energy loss. The large opening at the output end can reliably act on the delay tube 34 with the high-temperature gas generated during the operation of the launch stage engine, thereby improving the gas transfer efficiency.

[0045] Preferably, the inner diameter of the input end of the flame transfer tube 36 is larger than the inner diameter of the output end of the flame transfer tube 36, and the inner diameter of the output end of the flame transfer tube 36 is larger than the inner diameter of the middle part of the flame transfer tube 36. Among them, the flame transfer tube 36 is made of low-alloy high-strength steel, which can ensure that it is not damaged when reliably transferring the high-temperature gas generated during the operation of the launch stage engine to the delay tube 34, thereby maintaining the structural integrity.

[0046] In some embodiments, the delay tube 34 includes a housing, and slow-burning powder is contained in the housing. By controlling the burning rate of the slow-burning powder, after the delay tube 34 acts, energy can be reliably output from the output end within the specified delay time, and the ignition cartridge 31 can be ignited, thereby realizing the control of the delay ignition time of the delay tube 34. The delay tube 34 in this embodiment can realize an ignition time delay of 300 ms to 420 ms, meeting the requirements for the delay ignition time of the main stage engine. Preferably, the housing of the delay tube 34 is made of stainless steel.

[0047] The delay tube 34 in this embodiment is capable of being reliably acted on at the input end under the action of high-temperature gas at a specific pressure (1.0 MPa to 20.0 MPa) and within a certain flame transfer distance (within 100 mm), and can normally ignite the ignition cartridge 31 at a certain distance (60 mm) from the output end.

[0048] In this embodiment, the ignition cartridge 31 includes a housing, and ignition powder is contained in the housing. The housing is made of celluloid material. Under the action of the output end of the delay tube 34, the housing can burn rapidly, thereby igniting the ignition powder and realizing the ignition of the main stage engine.

[0049] This embodiment also provides a solid rocket motor, which includes a primary stage motor and a launch stage motor. The primary stage motor includes a charge combustion chamber, a tail pipe, and a nozzle; it also includes the delay ignition device described in any one of the above. The fixed bracket 33 is installed in the tail pipe, the ignition cartridge 31 is installed in the charge combustion chamber, and the flame transfer tube 36 is arranged in the nozzle and its input end is connected to the launch stage motor. The primary stage motor of this embodiment utilizes the high-temperature and high-pressure gas generated by the operation of the launch stage motor to achieve autonomous and reliable delay ignition through the delay ignition device. Therefore, the primary stage motor does not need to design an electrical interface for inputting ignition signals, nor does it need to add a dedicated ignition module and a security mechanism module and then control the ignition of the main engine through the on-board computer. Moreover, since there is no primary stage motor ignition module and ignition safety mechanism module in the control cabin, the overall structure of the entire missile can be made more compact, effectively shortening the length of the control cabin, thereby effectively controlling the total length of the missile. In addition, since the primary stage motor adopts autonomous and reliable delay ignition and the igniter has no lead wire led out, there is no need to consider the wiring and leading-out method of the igniter wire in the overall design of the solid rocket motor, and there is no need to consider the problem of pre-burying the ignition wire in the charge combustion chamber, which greatly facilitates the engine charge production and the engine general assembly production work. Moreover, since there is no need to design the missile wall cable on the missile, there is no missile wall cable cover for the entire missile, which can reduce the protrusion outside the missile body, thereby reducing the aerodynamic drag during missile flight.

[0050] Specifically, the front head is provided on the outer cover of the electric igniter of the launch stage motor. The input end of the flame transfer tube 36 is reliably connected to the front head of the launch stage motor through a thread, which can reliably transfer the high-temperature gas generated during the operation of the launch stage motor to the delay tube, and at the same time can ensure that when the launch stage motor is separated from the primary stage motor, the flame transfer tube 36 is retained in the launch tube together with the launch stage motor.

[0051] Optimizing the above embodiment, the ratio of the ventilation area of the fixed bracket 33 to the throat area of the nozzle is greater than 2:1. In this embodiment, the ventilation area of the fixed bracket 33 is the total area of the hollow region surrounded by the spokes of the middle spoke part 332 and the outer ring part 333, and this area is more than twice the throat area of the nozzle, ensuring that the high-temperature gas generated after the ignition cartridge 31 of the primary stage motor is ignited can smoothly discharge from the hollow region of the fixed bracket 33, ensuring the normal operation of the engine.

[0052] The implementation process of the solid rocket motor of this embodiment using the delay ignition device is as follows:

[0053] 1) The main charge of the launch stage motor is ignited, and the launch stage motor starts to operate;

[0054] 2) The high-temperature gas generated by the operation of the launch stage motor acts on the input end of the delay tube 34 through the flame transfer tube 36, and the delay tube 34 starts to operate after being acted on;

[0055] 3) After the launch stage engine moves to the front end of the launch tube, the launch stage engine is separated from the main stage engine, and the ignition transfer tube 36 and the delay tube 34 are separated simultaneously. The delay tube 34 is launched out of the tube with the main stage engine, and the ignition transfer tube 36 is retained in the launch tube with the launch stage engine.

[0056] 4) After the main stage engine is launched out of the tube at a predetermined initial velocity and flies a certain distance, the delay tube 34 is filled with a slow-burning propellant with a certain burning rate to control the ignition transfer time, so as to realize the delayed transfer of energy from the input end to the output end and ignite the ignition cartridge 31 of the main stage engine from the output end. The charge of the main stage engine is ignited, and the main stage engine starts to work.

[0057] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A delay ignition device, characterized in that: It includes an ignition cartridge for igniting the main-stage engine charge, a delay tube for delaying the ignition of the ignition cartridge, a fixing bracket for fixing the delay tube, and a fire-transfer tube for transferring the high-temperature gas generated during the operation of the launch-stage engine to the delay tube. The input end of the delay tube is connected to the output end of the fire-transfer tube, and the output end of the delay tube acts on the ignition cartridge.

2. The delay ignition device according to claim 1, wherein: The fixing bracket includes an inner ring part, an outer ring part, and an intermediate spoke part, and the inner ring part, the intermediate spoke part, and the outer ring part are sleeved on the delay tube in sequence from inside to outside.

3. The delay ignition device according to claim 2, wherein: On one side of the fixing bracket at the output end of the delay tube, there is a plug cover for blocking the intermediate spoke part during ignition and releasing the blockage after ignition.

4. The delay ignition device according to claim 3, wherein: The plug cover is made of an easily foamable molding material.

5. The delay ignition device according to claim 2, characterized in that: Both the outer ring part and the intermediate spoke part are made of a non-metallic composite material with erosion resistance and ablation resistance, and the inner ring part is made of a metal material.

6. The delay ignition device according to claim 1, characterized in that: The input end of the delay tube and the output end of the fire-transfer tube are in clearance fit with a shaft hole, and at least one sealing ring is arranged in the clearance between the delay tube and the fire-transfer tube.

7. The delay ignition device according to claim 1, characterized in that: The inner diameter of the input end of the fire-transfer tube and the inner diameter of the output end of the fire-transfer tube are both larger than the inner diameter of the middle part of the fire-transfer tube.

8. The delay ignition device according to claim 1, characterized in that: The delay tube includes a housing, and a slow-burning charge is installed in the housing.

9. A solid rocket engine, comprising a main-stage engine and a launch-stage engine, wherein the main-stage engine includes a charge combustion chamber, a tail pipe, and a nozzle; characterized in that: It also includes the delay ignition device according to any one of claims 1-8. The fixing bracket is installed in the tail pipe, the ignition cartridge is installed in the charge combustion chamber, and the fire-transfer tube is arranged in the nozzle and the input end is connected to the launch-stage engine.

10. The solid rocket motor according to claim 9, characterized in that: The ratio of the ventilation area of the fixing bracket to the throat area of the nozzle is greater than 2:1.

Images