A pneumatic amplifier

Abstract

The invention discloses a pneumatic amplifier. The technical scheme comprises a valve body, a middle cavity is formed in the valve body, an air inlet is formed on one side of the valve body, and the air inlet is connected to the middle cavity; an upper cover is detachably connected to the end of the valve body, an upper cavity for accommodating gas is formed between the upper cover and the valve body, a piston one is movably connected inside the upper cover, and the top of the piston one and the inner wall of the upper cover form a top cavity; a piston two is movably arranged in the middle cavity of the valve body; a bottom cover is detachably connected to the end of the valve body away from the upper cover, a dust cover plate is detachably connected to the end of the bottom cover, and a bottom cavity is formed inside the dust cover plate; a main valve core is movably connected in the middle cavity of the valve body, and the bottom of the main valve core extends deeply into the inner hole of the bottom cover; a piston rod, and the piston rod passes through piston one, piston two and the main valve core. The advantages of the invention are short response time, reduced motion error of components, and improved stability of equipment operation.

Description

Technical Field

[0001] The present invention relates to the field of control components for pneumatic systems, and particularly to a pneumatic amplifier. Background Art

[0002] A pneumatic amplifier is a control component in a pneumatic system, mainly used to receive the control air source pressure of a positioner, adjust the opening degree of the main air path, and meet the precise control of the stroke (rotation angle) of an actuator. There are various types of pneumatic amplifiers on the market currently. Along with the development of pneumatic systems towards large flow rates and high gas speeds, product upgrades and replacements are also required for pneumatic amplifiers.

[0003] There is a Chinese patent with the publication number CN2557735Y that discloses a diaphragm pneumatic amplifier, which includes an upper cavity cover, a lower cavity cover, a double-headed valve core, two diaphragms, a control air source inlet, an input air source inlet, and a gas outlet. A diaphragm is added below the two diaphragms to form upper, middle, and lower diaphragms; the upper and middle diaphragms are separated by a support member with ventilation holes, and the middle and lower diaphragms are riveted together by a separator; connected to the input air source, another input air source inlet leading to the inner cavity separated by the middle and lower diaphragms is also provided on the lower cavity cover, and an elastic element abuts between the valve core head and the lower cavity cover to play a micro-pressure reset role. Its working principle: through the elastic deformation of the diaphragms in the cavity, the spatial change of the working cavity is changed, and then the output air pressure is changed. However, the current pneumatic amplifier has the following problems:

[0004] 1. For a pneumatic amplifier to adapt to a pneumatic system with a large gas flow rate, more diaphragms need to be installed in the valve body. When the air pressure inside the valve body changes, the multiple diaphragms change sequentially, which takes a lot of time, resulting in the response speed not meeting the requirements.

[0005] 2. The number of diaphragms in the pneumatic amplifier is large, and the deformation of the multiple diaphragms has a certain and discrete error. As the diaphragms gradually age during the deformation process, the movement error of the components will be further amplified, affecting the stability of the pneumatic amplifier. Summary of the Invention

[0006] Aiming at the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a pneumatic amplifier, which has the advantages of short response time, reducing the movement error of components, and improving the stability of equipment operation.

[0007] The above technical purpose of the present invention is achieved through the following technical solutions:

[0008] A pneumatic amplifier:

[0009] It comprises a valve body, wherein a central cavity is formed in the valve body, an air inlet is formed on one side of the valve body, the air inlet is connected to the central cavity, and an air outlet is formed on the other side of the valve body, the air outlet is connected to the central cavity;

[0010] The valve body comprises an upper cover, which is detachably connected to the end of the valve body, an upper chamber for accommodating gas is formed between the upper cover and the valve body, a piston is movably connected inside the upper cover, a top chamber is formed between the top of the piston and the inner wall of the upper cover, a signal hole and an adjustment hole are opened on the upper cover, the signal hole is connected to the upper chamber of the adjustment hole, and a valve core is arranged in the adjustment hole;

[0011] It comprises a piston 2, the piston 2 is movably arranged in the middle cavity of the valve body, the piston 1 and the piston 2 are coaxially arranged, and the piston 1 and the piston 2 are elastically connected;

[0012] The valve body comprises a bottom cover, the bottom cover is detachably connected to the end of the valve body away from the upper cover, the bottom cover and the valve body enclose a lower cavity for accommodating gas, the end of the bottom cover is detachably connected to a dust cover plate, the dust cover plate has a bottom cavity formed therein, the dust cover plate has an exhaust hole, the exhaust hole is connected to the bottom cavity, and an inner hole is formed at the center of the bottom cover, the lower cavity is connected to the bottom cavity through the inner hole;

[0013] It includes a main valve core, which is arranged in a hollow shape, and is movably connected in the middle cavity of the valve body, and the bottom of the main valve core extends deeply into the inner hole of the bottom cover;

[0014] It includes a piston rod, the head and tail ends of which are respectively fixed on the upper cover and the bottom cover, the piston rod is located on the central axis of the valve body, and the piston rod passes through piston one, piston two and the main valve core in sequence.

[0015] Furthermore, a valve seat 1 is provided at the bottom of the regulating hole, and the valve seat 1 supports the bottom of the valve core 1.

[0016] Furthermore, the top of the valve core 1 extends out of the end surface of the upper cover, and the top of the valve core 1 is threadedly connected with a nut 1 for fixing the valve core 1.

[0017] Furthermore, a spring 1 in a compressed state is arranged between the piston 1 and the piston 2.

[0018] Furthermore, the cross section of the piston 2 is T-shaped, and a groove is provided on the bottom surface of the top plate of the piston 2.

[0019] Furthermore, a second spring in a compressed state is embedded in the outer side surface of the main valve core, one end of the second spring abuts against the main valve core, and the other end of the second spring abuts against the inner side of the bottom cover.

[0020] Furthermore, an oil-free bearing is installed on the inner wall of the inner hole of the bottom cover, and the oil-free bearing is in contact with the outer side of the main valve core.

[0021] Further, nuts are threadedly connected to both ends of the piston rod. The nut located above contacts the top surface of the first piston, and the nut located below contacts the bottom surface of the main valve core.

[0022] Further, the upper cover is provided with an air replenishing hole communicating with the top cavity. A first muffler is installed at the opening of the air replenishing hole, and a second muffler is installed at the opening of the exhaust hole.

[0023] Further, the upper cover and the valve body are detachably connected by screws, and the bottom cover and the valve body are detachably connected by screws.

[0024] In summary, the present invention has the following beneficial effects:

[0025] 1. Through the combined movement of the first piston, the second piston and the main valve core, the linkage of the three is more sensitive, so as to adjust the volume change of each cavity, accelerate the action speed of the control valve, realize the fast response of the pneumatic amplifier, and the volume of each cavity is large, so the stability is good and the debugging is convenient.

[0026] 2. The cross-sectional area of the flow channel formed by each cavity is large, and the CV value is higher, which can meet the use requirements of regulating and controlling the extreme working conditions of opening and closing in seconds.

[0027] 3. The diaphragm is not used inside, so the pressure resistance is higher and the service life is longer.

[0028] 4. Mufflers are installed at the air replenishing hole and the exhaust hole to reduce the noise generated during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic cross-sectional structure diagram of the initial state of the pneumatic amplifier.

[0030] Figure 2 is a schematic cross-sectional structure diagram of the pressure supply state of the pneumatic amplifier.

[0031] Figure 3 is a schematic cross-sectional structure diagram of the pressure relief state of the pneumatic amplifier.

[0032] In the figure: 1. Valve body; 11. Upper cavity; 12. Middle cavity; 13. Lower cavity; 14. Air inlet hole; 15. Air outlet hole; 2. Upper cover; 21. Signal hole; 22. Adjusting hole; 221. First valve core; 222. Nut; 223. First valve seat; 23. First piston; 231. First guide ring; 232. First spring; 24. Top cavity; 241. Air replenishing hole; 242. First muffler; 3. Second piston; 4. Main valve core; 41. Second spring; 42. Oil-free bearing; 5. Bottom cover; 51. Dust-proof cover plate; 52. Bottom cavity; 53. Exhaust hole; 531. Second muffler; 6. Piston rod. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the device proposed by the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are in a very simplified form and all use non-precise scales, only for the purpose of conveniently and clearly assisting in explaining the embodiments of the present invention. In order to make the objectives, features and advantages of the present invention more obvious and understandable, please refer to the accompanying drawings. It should be noted that the structures, scales, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they do not have technical substance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the objectives that can be achieved, should still fall within the scope covered by the technical content disclosed by the present invention.

[0034] Embodiment:

[0035] A pneumatic amplifier, as Figure 1 shown, includes a valve body 1, an upper cover 2 and a bottom cover 5. The upper cover 2 and the bottom cover 5 are respectively detachably connected to the ends of the valve body 1, thereby closing both ends of the valve body 1.

[0036] Specifically, as Figure 1 shown, a middle cavity 12 is formed in the valve body 1. An air inlet hole 14 is formed on one side surface of the valve body 1. The air inlet hole 14 is a stepped hole, and internal threads are engraved on the inner wall of the air inlet hole 14 for intercepting with an external pipeline joint. The air inlet hole 14 communicates with the middle cavity 12. An air outlet hole 15 is formed on the other side surface of the valve body 1. The air outlet hole 15 is also a stepped hole, and internal threads are provided on the inner wall of the air outlet hole 15. The air outlet hole 15 communicates with the middle cavity 12.

[0037] Specifically, as Figure 1 shown, the upper cover 2 and the end of the valve body 1 are installed together by screws. A spring washer is provided at the position where the screw head contacts the upper cover 2 to prevent the screw from wearing the surface of the upper cover 2 during the installation process. An upper cavity 11 for accommodating gas is formed between the upper cover 2 and the valve body 1. A first piston 23 is movably connected inside the upper cover 2. The first piston 23 is located at the central axis of the upper cover 2. During operation, the first piston 23 reciprocates along the axial direction of the valve body 1. A first guide ring 231 is embedded on the outer peripheral surface of the first piston 23. The first guide ring 231 contacts the inner wall of the through hole of the upper cover 2. The first guide ring 231 plays a guiding role when the first piston 23 moves, ensuring that the first piston 23 can only perform axial reciprocating motion.

[0038] Specifically, as Figure 1As shown, the top of piston 1-23 and the inner wall of the upper cover 2 enclose a top cavity 24. The upper cover 2 is provided with an air compensation hole 241 communicating with the top cavity 24. During operation, air is introduced into the top cavity 24 through the air compensation hole 241 to increase the pressure, and then the top cavity 24 is driven to move. A muffler 1-242 is installed at the port of the air compensation hole 241 to reduce noise.

[0039] Specifically, as Figure 1 shown, the upper cover 2 is provided with a signal hole 21. The signal hole 21 is arranged along the thickness direction of the upper cover 2 and communicates with the upper cavity 11. When the device starts to operate, air enters through the signal hole 21 to increase the pressure in the upper cavity 11.

[0040] Specifically, as Figure 1 shown, the upper cover 2 is provided with an adjustment hole 22. The adjustment hole 22 is arranged along the thickness direction of the upper cover 2 and communicates with the upper cavity 11. A valve core 1-221 is arranged in the adjustment hole 22. The top of the valve core 1-221 extends out of the end face of the upper cover 2. A nut 1-222 is threadedly connected to the head of the valve core 1-221. After the position of the valve core 1-221 is adjusted, the staff tightens the nut 1-222 to fix the valve core 1-221. A plurality of annular grooves are formed on the outer side surface of the valve core 1-221, and an O-ring is installed in the annular groove. The O-ring is located between the valve core 1-221 and the inner wall of the adjustment hole 22 to fill the gap and improve the sealing performance. A valve seat 1-223 is installed at the bottom of the adjustment hole 22. The bottom end of the valve core 1-221 passes through the valve seat 1-223, and the valve seat 1-223 is used to support the bottom of the valve core 1-221.

[0041] Specifically, as Figure 1 shown, it includes a piston 2-3. The piston 2-3 is movably arranged in the middle cavity 12 of the valve body 1. The piston 1-23 and the piston 2-3 are coaxially arranged, and the piston 1-23 and the piston 2-3 are elastically connected. A spring 1-232 in a compressed state is arranged between the piston 1-23 and the piston 2-3. In the initial state, the spring 1-232 drives the piston 2-3 to move downward to close the middle cavity 12. In the working state, when the pressure in the middle cavity 12 increases after air is introduced, the piston 2-3 is driven to move upward against the elastic force of the spring 1-232 to open the middle cavity 12.

[0042] Specifically, as Figure 1 shown, the cross-section of the piston 2-3 is T-shaped, that is, the piston 2-3 is umbrella-shaped. A groove is arranged on the bottom surface of the top plate of the piston 2-3. Because the bottom surface of the top plate of the piston 2-3 is the force-bearing surface, such an outer shape design obtains the largest wind-receiving area in the available space.

[0043] Specifically, as Figure 1As shown in the figure, it includes a main spool valve 4. The main spool valve 4 is set to be hollow, and the cross-sectional outer shape of the main spool valve 4 is pear-shaped, increasing the cross-sectional area for ventilation. The main spool valve 4 is movably connected in the middle cavity 12 of the valve body 1. A second compressed spring 41 is embedded on the outer side of the main spool valve 4. One end of the second spring 41 abuts against the main spool valve 4, and the other end of the second spring 41 abuts against the inner side of the bottom cover 5. The second spring 41 provides an elastic restoring force to the main spool valve 4. In the initial state, under the action of the second spring 41, the main spool valve 4 is driven to move upward, so that the main spool valve 4 abuts against the second piston 3.

[0044] Specifically, as Figure 1 shown in the figure, the bottom cover 5 is also detachably connected to the end of the valve body 1 away from the upper cover 2 by screws. The cover and the valve body 1 enclose a lower cavity 13 for accommodating gas. An inner hole is opened at the center of the bottom cover 5, and the bottom of the main spool valve 4 deeply extends into the inner hole of the bottom cover 5. An oil-free bearing 42 is installed on the inner wall of the inner hole, and the inner side of the oil-free bearing 42 contacts the outer side of the main spool valve 4, reducing the frictional resistance received by the main spool valve 4 through the oil-free bearing 42.

[0045] Specifically, as Figure 1 shown in the figure, a dust-proof cover plate 51 is detachably connected to the end of the bottom cover 5. A bottom cavity 52 is opened inside the dust-proof cover plate 51, and the main spool valve 4 communicates with the bottom cavity 52. An exhaust hole 53 is opened on the dust-proof cover plate 51, and the exhaust hole 53 communicates with the bottom cavity 52. An inner hole is opened at the center of the bottom cover 5, and the lower cavity 13 and the bottom cavity 52 are communicated through the inner hole. A second muffler 531 is installed at the opening of the exhaust hole 53 to reduce the noise generated by exhaust.

[0046] Specifically, as Figure 1 shown in the figure, it includes a piston rod 6. The piston rod 6 is arranged on the central axis of the valve body 1. The piston rod 6 passes through the first piston 23, the second piston 3 and the main spool valve 4. Nuts 222 are threadedly connected to the upper end and the lower end of the piston rod 6. The main function of the upper nut 222 is to limit the extreme position of the movement of the first piston 23; the lower nut 222 is mainly used to limit the extreme position of the movement of the main spool valve 4. During the working process, the first piston 23, the second piston 3 and the main spool valve 4 make corresponding reciprocating movements on the piston rod 6.

[0047] Specific working process:

[0048] The amplifier performs the first action and provides to the actuator:

[0049] (1), Starting state; as Figure 1As shown in the figure, after the installation of the equipment components is completed, the equipment is not ventilated. Due to the action of spring 1 - 232, the first piston 23 is driven to move upward to the limit position, and the second piston 3 is driven to move downward to the limit position. Due to the action of spring 2 - 41, the main spool 4 moves upward to the limit position. At this time, the main spool 4 abuts against the second piston 3, and the top chamber 24, the upper chamber 11, the middle chamber 12, the lower chamber 13, and the bottom chamber 52 are all not connected.

[0050] (2) Pneumatic amplifier action 1: As Figure 2 shown in the figure, the air inlet hole 14 (denoted as the P port) is filled with gas with a pressure of 0.1 - 1.0 MPa, and the gas is sealed in the lower chamber 13. The signal hole 21 is filled with gas with a pressure of 0.02 - 0.7 MPa, and the gas is sealed in the upper chamber 11. The pressure in the upper chamber 11 is greater than that in the middle chamber 12. The second piston 3 pushes the main spool 4 to move downward against the thrust of spring 2 - 41. The first piston 23 moves downward with the main spool 4 through the piston rod 6 and the nut 222. The lower chamber 13 and the middle chamber 12 are connected, and the gas in the air inlet hole 14 can flow into the air outlet (denoted as the A port), and then is transported to the external actuator from the air outlet. The top chamber 24 is filled with supplementary air, and the bottom chamber 52 is closed until the actuator moves to the preset position. In this process, the stroke of the main spool 4 is related to the air pressure received by the signal hole 21 overcoming the thrust of spring 2 - 41.

[0051] (3) Pneumatic amplifier action 2: As Figure 3 shown in the figure, the actuator exhausts and relieves pressure through the pneumatic amplifier. As the air pressure received by the signal hole 21 from the positioner approaches 0, the pressure in the upper chamber 11 is less than the pressure in the middle chamber 12. When the pressure in the middle chamber 12 exceeds the thrust of spring 1 - 232, the second piston 3 moves upward, and the main spool 4 also returns to its original position under the thrust of spring 2 - 41, closing the channel between the middle chamber 12 and the lower chamber 13. The air inlet hole 14 and the air outlet hole 15 are not connected. At this time, the residual pressure in the air outlet hole 15 is still greater than the pressure in the upper chamber 11. When the thrust of the residual pressure in the air outlet hole 15 exceeds the thrust of spring 1 - 232, the second piston 3 moves further upward, and the sealing surface between the main spool 4 and the second piston 3 disengages. The middle chamber 12 is connected to the bottom chamber 52, and the residual pressure is emptied. The first piston 23 is pushed to the uppermost end by spring 1 - 232, driving the piston rod 6 and the sealing surface of the main spool 4 to further press on the valve body 1, ensuring that the gas in the lower chamber 13 is sealed in the lower chamber 13. After the residual pressure is emptied, spring 1 - 232 resets, and the sealing surface of the second piston 3 coincides with the sealing surface of the main spool 4, and each chamber is sealed and not connected, returning to the initial state.

[0052] (4) After the installation of the device is completed, debugging is carried out. Adjust the position of the first spool 221 above the adjustment hole 22 to make there be a slight pressure feedback between the air outlet hole 15 and the upper chamber 11. After adjustment, tighten it with the nut 222. To ensure accurate positioning and without overshoot or air replenishment, ensure the stability of the pneumatic system.

[0053] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0054] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A pneumatic amplifier, characterized in that: It includes a valve body with a middle cavity formed therein. An air inlet hole is formed on one side surface of the valve body, and the air inlet hole communicates with the middle cavity. An air outlet hole is formed on the other side surface of the valve body, and the air outlet hole communicates with the middle cavity; It includes an upper cover detachably connected to the end of the valve body. An upper cavity for containing gas is formed between the upper cover and the valve body. A first piston is movably connected inside the upper cover. A top cavity is formed between the top of the first piston and the inner wall of the upper cover. A signal hole and an adjustment hole are formed on the upper cover. The signal hole communicates with the upper cavity of the adjustment hole, and a first valve core is arranged in the adjustment hole; It includes a second piston movably arranged in the middle cavity of the valve body. The first piston and the second piston are coaxially arranged and elastically connected between them; It includes a bottom cover detachably connected to the end of the valve body away from the upper cover. A lower cavity for containing gas is formed between the bottom cover and the valve body. A dust-proof cover plate is detachably connected to the end of the bottom cover. A bottom cavity is formed inside the dust-proof cover plate. An exhaust hole is formed on the dust-proof cover plate, and the exhaust hole communicates with the bottom cavity. An inner hole is formed at the center of the bottom cover, and the lower cavity and the bottom cavity are communicated through the inner hole; It includes a main valve core which is hollow. The main valve core is movably connected in the middle cavity of the valve body, and the bottom of the main valve core deeply extends into the inner hole of the bottom cover; It includes a piston rod with its head and tail ends respectively fixed to the upper cover and the bottom cover. The piston rod is located on the central axis of the valve body and sequentially passes through the first piston, the second piston and the main valve core; A first spring in a compressed state is arranged between the first piston and the second piston; The cross section of the second piston is T-shaped, and a groove is arranged on the bottom surface of the top plate of the second piston; A second spring in a compressed state is embedded on the outer side surface of the main valve core. One end of the second spring abuts against the main valve core, and the other end of the second spring abuts against the inner side of the bottom cover; The upper cover is provided with a supplementary air hole communicating with the top cavity, and a first muffler is installed at the opening of the supplementary air hole. A second muffler is installed at the opening of the exhaust hole.

2. The pneumatic amplifier according to claim 1, wherein: A first valve seat is arranged at the bottom of the adjustment hole, and the first valve seat supports the bottom of the first valve core.

3. The pneumatic amplifier according to claim 2, characterized in that: The top of the first valve core extends out of the end face of the upper cover, and a first nut for fixing the first valve core is threadedly connected to the top of the first valve core.

4. The pneumatic amplifier according to claim 1, characterized in that: An oil-free bearing is installed on the inner wall of the inner hole of the bottom cover, and the oil-free bearing contacts the outer side of the main valve core.

5. The pneumatic amplifier according to claim 4, characterized in that: Nuts are threadedly connected to both ends of the piston rod. When in the initial state, the upper nut contacts the top surface of the first piston, and the lower nut contacts the bottom surface of the main valve core.

6. The pneumatic amplifier according to claim 1, wherein: The upper cover and the valve body are detachably connected by screws, and the bottom cover and the valve body are detachably connected by screws.

Images