Carbon fiber composite valve and method of designing the same

Abstract

The application relates to a carbon fiber composite material valve and a design method thereof, and belongs to the field of valve design. The actual valve body is internally provided with a metal material, and the outer layer is coated with CFRP material. The two materials are integrally formed through epoxy resin gluing. The thickness of the CFRP material coated at different positions of the valve body is different. The positions with relatively thick CFRP layers are the inner surfaces of the flanges at two ends, the outer walls of the positions connected with large bolts and the annular outer walls along the flow direction of the valve body. The remaining regions are only coated with relatively thin CFRP layers as the appearance, so that the complete carbon fiber composite material valve body is formed. Meanwhile, the application also comprises a design method of the carbon fiber composite material valve. The valve body of the valve designed by the application is provided with CFRP material instead of part of the metal material. The advantages of low density and strong vibration resistance of the CFRP material are utilized to realize the weight reduction and noise reduction of the carbon fiber composite material valve, and the disadvantages of the traditional metal valve, such as large weight and large noise, are improved. The application is beneficial to the forming process of the CFRP material.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of valve design, and relates to a carbon fiber composite material valve and a design method thereof. BACKGROUND

[0002] At present, the weight of the traditional metal valve of a ship or a boat is large, and the weight of a large-diameter valve can be more than one ton. The ship or the boat usually has a large number of valves and a long and complex pipeline, so that the valve system occupies a large weight ratio. In terms of transportation, the large-weight valve system affects the overall cargo capacity, passenger capacity and fuel efficiency of the ship, and affects the transportation cost. In terms of installation and maintenance, the over-heavy valve increases the difficulty of installation and maintenance, and wastes manpower and material resources. At the same time, the over-heavy valve itself also has greater safety hazards. Therefore, the lightweight design of the valve can improve the safety factor of the entire ship or boat, reduce the transportation cost and improve the overall performance.

[0003] Because the valve pipeline system of the ship or the boat covers a wide range and has a complex structure, the noise generated thereby is large. The excessive noise not only affects the hearing health of the operator, but also affects the stealth capability of the entire ship or boat. At the same time, the excessive amplitude of the traditional metal valve also affects the service life thereof. At present, the method of increasing a silencing device or wrapping a damping material is mostly used to reduce the noise of the valve, but these methods further increase the weight of the valve system. Therefore, the improvement of the structure or the material of the valve itself can reduce the noise of the valve without increasing the weight of the valve.

[0004] Carbon fiber reinforced plastic (CFRP) is a damping material with the advantages of light weight, high specific strength, good specific stiffness, strong designability and excellent vibration reduction performance, which is beneficial to reduce the vibration of the structure. At present, CFRP is widely used in the fields of automobiles and aerospace. Compared with the traditional metal material, CFRP can not only significantly reduce the weight of the structure, but also improve the strength of the structure to a certain extent, and can further improve the safety and stability of the structure due to the vibration reduction performance. Therefore, the application of CFRP to the valve structure and the replacement of part of the metal on the outside of the valve body with CFRP material can not only realize the lightweight of the valve system, but also reduce the vibration of the valve to achieve the purpose of noise reduction. SUMMARY

[0005] In view of the shortcomings of the traditional metal valve, such as large weight and large noise, the CFRP material is used to replace part of the outer wall material of the original metal regulating valve body, and the CFRP and the metal valve body liner are glued together by epoxy resin to form a complete valve body structure, so as to reduce the weight of the valve and reduce the noise generated during the operation of the valve by using the vibration reduction performance of the CFRP.

[0006] To achieve the above object, the technical scheme adopted by the present application is:

[0007] A carbon fiber composite material valve, the carbon fiber composite material valve comprises a valve body 2, a spring gland 3, a valve seat 4, a ball 5, a spring 6, a diffuser 7, a hole plate 8, a flow guide sleeve 9, a large bolt 10, a guide sleeve 11, a valve rod 12, an upper cover 13 and a sealing element. Compared with the traditional metal valve, the design improvement point (improvement of the original metal valve body) of the present application is that the valve body 2 is a valve body structure composed of two basic materials of metal material and CFRP material, which is formed by bonding the metal material as the inner liner 201 and the CFRP material as the outer layer 202 to form the CFRP layer, and the two materials are bonded to form a whole by epoxy resin, wherein the thickness of the CFRP material coated at different positions of the valve body 2 is different. Specifically:

[0008] Further, the position of the thicker CFRP layer is the inner side of the flange 205 at both ends, the outer wall of the position 206 connected to the large bolt and the annular outer wall 203 along the flow direction of the valve body 2, and the remaining outer surface area is only coated with a thinner CFRP layer as an appearance, forming a complete carbon fiber composite material valve body.

[0009] Further, the carbon fiber composite material valve structure specifically comprises:

[0010] The valve body 2 is provided with a thread 207 at the inlet for connecting the spring gland 3, the spring gland 3 is matched with the outer wall surface of the valve seat 4 through a gap, the valve seat 4 is contacted with the ball 5 through a dynamic sealing ring, and the valve seat 4 is fixed and constrained through the pressing force generated by the spring 6 between the spring gland 3 and the valve seat 4 and the contact of the ball 5.

[0011] The valve body 2 is provided with a thread 208 at the outlet for connecting the diffuser 7, the diffuser 7 is contacted with the hole plate 8, the hole plate 8 is contacted with the flow guide sleeve 9, and the hole plate 8 and the flow guide sleeve 9 are fixed and constrained through the contact of the inner wall structure of the valve body 2 and the diffuser 7.

[0012] The valve body 2 is provided with a through hole 209 in the flange 204 at the upper end for placing the valve rod 12 and the upper cover 13, and the valve rod 12 is embedded into the ball 5 at the end to control the rotation of the ball 5 and limit the degree of freedom.

[0013] The valve body 2 is provided with a thread 211 at the lower end for connecting the large bolt 10, and the large bolt 10 is connected with the ball 5 through the guide sleeve 11 at the end to limit the degree of freedom of the ball 5.

[0014] The valve body 2 is provided with a plurality of through holes 212 in the flanges 205 at both sides for bolt connection of the valve body 2 and the pipeline accessories.

[0015] A design method of carbon fiber composite material valve, comprising the following steps:

[0016] Firstly, the original metal valve body 1 is structurally improved. As shown in Figure 1 and 2 , the inclined curved surface annular outer wall 101 of the original metal valve body 1 is changed to the equal-diameter curved surface outer wall 203 of the valve body 2; the flange of the middle flange 102 of the original titanium alloy valve body 1 is removed, and the structure of the middle flange 204 of the valve body 2 is changed, which is used for the winding forming of the CFRP prepreg.

[0017] Secondly, the main stress position of the valve body 2, i.e. the annular outer wall 203 along the flow direction of the valve body 2, is selected, the CFRP material is used to replace part of the metal material of the outer wall at the position, and the thickness range of the replaced CFRP material is determined by using the equal stiffness replacement formula. The formula is:

[0018]

[0019] In the formula, t M and t C are the thicknesses of the metal material before replacement and the CFRP material after replacement respectively; E M and E C are the metal stiffness and the annular stiffness of the CFRP coated valve body respectively; and α is a thickness index coefficient, which is usually taken as 1-3.

[0020] According to the value range of α, the value range [t a , t b ] of t T is determined.

[0021] According to the value range [t a , t b ] of t T , the valve bodies with different thicknesses of CFRP in the range are selected to perform static simulation. The single-layer thickness t0 of the CFRP prepreg is a fixed value, so the value of t T in [t a , t b ] is a discrete value, and a thickness value t i (i=1, 2, 3, …, m) is selected for each additional n layers of CFRP material, and t i+1 =t i +nt0 is satisfied. That is, the valve bodies with CFRP of t1, t2, t3…t m thicknesses in the range of [t a , t b ] are selected to perform static simulation.

[0022] Thirdly, according to the static simulation results of the second step, the maximum stresses σ i(i = 1, 2, 3, …, m) and the maximum stress of the original metal valve body T The thickness value t closest to the selection result is selected i (i = 1, 2, 3, …, m) as the final thickness t of the CFRP layer F That is, the finally determined CFRP thickness should satisfy the following relationship:

[0023]

[0024] Fourthly, the inner sides of the two side end flanges 103 of the valve body 1 and the outer walls of the connecting large bolt positions 104 are replaced with equal thickness, that is, the original part of the metal material is removed, and the thicknesses are t Mf and t Mb , and the CFRP material with equal thickness is coated on the surface, and the thicknesses are t Cf and t Cb , wherein t Mf =t Cf , t Mb =t Cb . The remaining outer surface area, that is, the edges and outer sides of the end flanges, the surface of the middle flange, and the lower edges of the large bolt positions are only coated with 1-2 layers of CFRP layer as appearance, so as to form a complete carbon fiber composite valve body.

[0025] Fifthly, all the contact surfaces between the CFRP material and the metal material are glued by epoxy resin glue to form a CFRP valve body.

[0026] The beneficial effects of the present application are:

[0027] (1) The valve body of the valve designed in the present application is replaced with CFRP material instead of part of the metal material, so that the advantages of low density and strong vibration resistance of CFRP can be utilized to realize the weight reduction and noise reduction of the carbon fiber composite valve, and the disadvantages of the traditional metal valve, such as large weight and large noise, can be improved.

[0028] (2) The valve body designed in the present application uses a metal valve body with improved shape as the inner liner, and the CFRP material is coated on the outside, and other parts still use metal materials, which is not only beneficial to the forming process of the CFRP material, but also avoids the hygrothermal aging caused by the direct contact of the CFRP material with water or seawater and other media.

[0029] (3) The metal outer surface of the present application is fully coated with CFRP material, which not only avoids the delamination at the edge of the CFRP and metal glue joint, but also makes the shape more beautiful.

[0030] (4) The design of the present application replaces part of the metal material with CFRP material in the main stress position of the valve body of the valve, which can ensure the mechanical properties of the valve body to a certain extent while reducing the weight of the valve body. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a schematic diagram of a valve body structure of a valve made of a base metal.

[0032] Figure 2 is a schematic diagram of a valve body structure of a valve made of a carbon fiber composite material according to the present application.

[0033] Figure 3 is Figure 1 is a schematic diagram of a valve body structure of a valve made of a carbon fiber composite material.

[0034] Figure 4 is a schematic diagram of a valve body structure of a valve made of a carbon fiber composite material.

[0035] Figure 5 is a flow chart of a design method of a valve made of a carbon fiber composite material.

[0036] Figure: 1 base titanium alloy valve body; 2 valve body; 3 spring cover; 4 valve seat; 5 ball; 6 spring; 7 diffuser; 8 orifice plate; 9 flow guide sleeve; 10 large bolt; 11 guide sleeve; 12 valve stem; 13 upper cover; 14 bolt;

[0037] 101 annular outer wall; 102 middle flange; 103 end flange; 104 large bolt position; 201 inner liner; 202 outer layer; 203 annular outer wall; 204 middle flange; 205 end flange; 206 large bolt position; 207 thread; 208 thread; 209 through hole; 210 threaded hole; 211 thread; 212 through hole. DETAILED DESCRIPTION

[0038] The present application will be described in detail below with reference to the accompanying drawings and embodiments.

[0039] As shown in Figure 2 and Figure 3 , a valve body of a valve made of a carbon fiber composite material. The valve body 2 is a valve body composed of two basic materials, metal and CFRP. The valve body is made of a metal material 201 as an inner liner, an outer layer coated with a CFRP material 202, and the two materials are integrally formed by epoxy resin bonding.

[0040] As shown in Figure 3 , in this embodiment, the thickness of the CFRP material coated at different positions of the valve body 2 is different, wherein the positions with thicker CFRP layer are the inner sides of the two end flanges 205, the outer wall connecting the large bolt position 206, and the annular outer wall 203 along the flow direction of the valve body, and the remaining areas are only coated with a thin CFRP layer as an appearance, thereby forming a complete carbon fiber composite material valve body.

[0041] As shown in Figure 3 and Figure 4In this embodiment, a thread 207 is machined at the inlet of the valve body 2 for connecting to the spring gland 3. The spring gland 3 is clearance-matched with the outer wall of the valve seat 4. The valve seat 4 contacts the ball 5 via a dynamic sealing ring. At the same time, the valve seat 4 is fixed and constrained by the compression force generated by the spring 6 between the spring gland 3 and the valve seat 4, as well as the contact with the ball 5.

[0042] like Figure 3 and Figure 4 In this embodiment, a thread 208 is machined at the outlet of the valve body 2 for connecting to the diffuser 7. The diffuser 7 contacts the orifice plate 8, which in turn contacts the guide sleeve 9. The orifice plate 8 and the guide sleeve 9 are fixedly constrained by the contact between the inner wall structure of the valve body 2 and the diffuser 7.

[0043] like Figure 3 and Figure 4 In this embodiment, the middle flange 204 of the valve body 2 is processed with a through hole 209 for receiving the valve stem 12 and the upper cover 13. The end of the valve stem 12 is embedded in the ball 5 to control the rotation of the ball 5 and limit its freedom.

[0044] like Figure 3 Shown and Figure 4 In this embodiment, six threaded holes 210 are machined around the through hole 209 of the valve body 2 for connecting the valve body 2 with the bolts 14 of the upper cover 13, which is used to connect the valve actuator.

[0045] like Figure 3 and Figure 4 In this embodiment, a thread 211 is processed on the lower end of the valve body 2 for connecting a large bolt 10. The end of the large bolt 10 is connected to the ball 5 through a guide sleeve 11 to limit the freedom of the ball.

[0046] like Figure 3 and Figure 4 In this embodiment, six through holes 212 are processed on each of the flanges 205 on both sides of the valve body 2 for bolt connection between the valve body 2 and pipeline accessories.

[0047] like Figure 5 As shown. The design method of carbon fiber composite valve is:

[0048] The first step is to improve the structure of the original metal valve body 1. Figure 1 and 2 As shown, the oblique curved annular outer wall 101 of the original metal valve body 1 is replaced with the equal-diameter curved outer wall 203 of the valve body 2; the flange of the middle flange 102 of the original titanium alloy valve body 1 is removed and replaced with the middle flange 204 structure of the valve body 2 for winding molding of CFRP prepreg.

[0049] Second step, select the main stress position of valve body 2, that is, the annular outer wall 203 along the flow direction of valve body 2, replace part of the metal material of the outer wall at this position with CFRP material, and determine the thickness range of the replaced CFRP material by using the equal stiffness replacement formula. The formula is:

[0050]

[0051] In the formula, t M , t C are the thicknesses of the metal material before replacement and the CFRP material after replacement respectively; E M , E C are the stiffness of the metal and the annular stiffness of the CFRP covering the valve body respectively, wherein E M =110MPa and E C =66MPa; and α is the thickness index coefficient, usually taking a value of 1-3.

[0052] According to the value range of α and taking t M =3mm, the value range of t T is determined to be [3.6mm, 5.0mm].

[0053] According to the value range [3.6mm, 5.0mm] of t T , the valve body with different thickness of CFRP in the range is selected for statics simulation, the single-layer thickness of the CFRP prepreg is 0.2mm, so the value of t T is a discrete value, and a thickness value is selected every 3 layers of CFRP material and t i+1 =t i +0.6mm. That is, the valve body with CFRP of thickness t1=3.6mm, t2=4.2mm and t3=4.8mm in the range [t a , t b ] is selected for statics simulation. The simulation results are shown in Table 1.

[0054] Table 1 Valve simulation results

[0055]

[0056] Third step, according to the statics simulation results of the second step, compare the maximum stresses σ i (i=1, 2, 3) of the valve body with different thickness of CFRP layer with the maximum stress σ T of the original metal valve body. Select the thickness value t i (i=1, 2, 3) closest to the result as the final thickness t F of the CFRP layer. That is, the finally determined thickness of the CFRP should satisfy the following relationship:

[0057]

[0058] The final determined CFRP thickness t3=4.8mm can be obtained by the simulation result values of Table 1 and formula (2).

[0059] In the fourth step, the inner side of the two end flanges 103 of the valve body 1 and the outer wall of the position 104 where the large bolt is connected are replaced by CFRP with equal thickness, i.e. the original part of metal material is removed, and the thicknesses are t Mf =5mm and t Mb =3mm, respectively, and the CFRP material with equal thickness is coated on the surface, and the thicknesses are t Cf =5mm and t Cb =3mm. The remaining outer surface area, i.e. the edge and outer side of the end flange, the surface of the middle flange and the lower edge of the position of the large bolt, is only coated with 2 layers of CFRP layer as appearance, so as to form a complete carbon fiber composite valve body. All the contact surfaces between the CFRP material and the metal material are glued by epoxy resin glue to form the CFRP valve body.

[0060] The above-described embodiments only express the implementation manners of the present application, and cannot be understood as the limitation of the scope of the present application patent. It should be pointed out that, for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application.

Claims

1. A method for designing a carbon fiber composite valve, wherein the valve comprises a valve body, wherein the valve body is a composite valve structure composed of a metal material and a CFRP material, wherein the metal material serves as an inner liner and the outer layer is coated with a CFRP material to form a CFRP layer, wherein the thickness of the CFRP material coated at different positions on the valve body varies, and wherein: The following steps are involved: The first step is to change the beveled curved annular outer wall of the original metal valve body into a constant diameter curved outer wall; remove the center flange of the original titanium alloy valve body and replace it with a center flange structure of the valve body for winding molding of CFRP prepreg; In the second step, the main stress-bearing position of the valve body is selected. The outer wall along the flow direction of the valve body is made of CFRP material, and the thickness range of the CFRP material is determined using the equal stiffness replacement formula; the formula is: （1）； Where: 、 are the thickness of the metal material before replacement and the thickness of the CFRP material after replacement respectively; 、 are the metal stiffness and the CFRP hoop stiffness of the valve body; is the thickness index coefficient; according to The value range of The value range of ; according to The value range of , select valve bodies with different thicknesses of CFRP within the range for static simulation, the thickness of the single layer of CFRP prepreg is a fixed value, exist The value in is a discrete value. Layer CFRP material takes a thickness value , , and satisfies ; That is, Take within the range 、 、 … Static simulation of the valve body made of CFRP with a thickness of 100 mm; The third step is to compare the maximum stress of the valve body with different thicknesses of CFRP layers based on the static simulation results of the second step. Maximum stress with original metal valve body ; Select the thickness value that is closest to the result As the final thickness of the CFRP layer ; The CFRP thickness determined should satisfy the following relationship: （2）； Step 4: The inner side of the flanges on both sides of the valve body and the outer wall of the connecting bolt position are designed with equal thickness. The thickness of the CFRP layer is and The edges and outer sides of the end flanges, the surface of the middle flange, and the lower edge of the large bolt position are only covered with 1 to 2 layers of CFRP as the exterior, forming a complete carbon fiber composite valve body. In the fifth step, all contact surfaces between the CFRP material and the metal material are bonded with epoxy resin glue to form the CFRP valve body.

2. The method for designing a carbon fiber composite material valve according to claim 1, characterized in that: In the second step The value range is 1~3.

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