CN115815052A - Striker for fluid ejection, nozzle, and fluid ejection device - Google Patents

Abstract

The invention relates to a firing pin for fluid injection. The firing pin is a hammer head firing pin. The head of the firing pin is composed of a section for pushing the fluid injection and a cylindrical surface for guiding the fluid to discharge in the opposite direction. The section for pushing the fluid injection is elliptical. Shaped or similar to an elliptical cross-section, the length of the semi-axis in the horizontal direction of the cross-section is greater than the length of the semi-axis in the vertical direction. Further, the striker shown in the present invention can also have a groove or rib structure; the present invention Also provided is a nozzle for fluid injection, characterized in that the nozzle has a structure in which the diameter gradually changes toward the outlet direction, the upstream part of the nozzle has a larger diameter, and the downstream part of the nozzle has a smaller diameter.

Description

Fluid jetting needle, nozzle and fluid jetting device

technical field

The invention relates to a striker for fluid injection, a nozzle and a fluid injection device, in particular to a hammerhead striker for high-viscosity fluid.

Background technique

The fluid micro-injection device is a device that precisely distributes fluid in a controlled manner. It is one of the key technologies in the microelectronics packaging industry. The fluid generates a pressure gradient under the action of the driving source. Under the action of the internal and external pressure difference Accelerated ejection from the nozzle, forming a fluid jet, and finally falling on the substrate to form a fluid spot.

With the continuous development of ultra-fine micromachining technology, the volume of precision components is getting smaller and smaller. At the same time, the requirements for micro-assembly and connection packaging technology of these precision components are also getting higher and higher. Micro-injection technology is currently one of the main methods of micro-assembly , so micro-injection technology plays a key role in the development of semiconductors, microelectronics packaging and other fields. The injection quality is mainly judged by the volume stability of the fluid point and whether it can be ejected from the nozzle smoothly. There are many factors that affect the injection quality, mainly including fluid viscosity, control temperature, feed pressure, flow channel shape, valve stem stroke, and power source. parameters etc. The disclosed prior art is as follows:

The authorized notification number is CN102615018B, which provides a micro-fluid quantitative distribution device, which uses a piezoelectric chip as the driving source to drive the striker to make a micro-reciprocating motion of 0.3-0.5mm. The key flow path of the injection valve is formed between the striker head and the nozzle. The dispensing cavity is filled with fluid between the firing pin and the cavity. When the firing pin hits the nozzle base, the flowing glue is cut off, and at the same time, a huge pressure is formed in the nozzle, and the glue is ejected to form glue droplets. Fig. 6 and Fig. 7 of the manual are schematic diagrams of fluid flow in the dispensing chamber when the striker moves downward and upward respectively. When the striker moves downward, part of the fluid flows downward and part of the fluid flows upward. The fluid in the nozzle absorbs the momentum of the striker. Rapid jetting forms droplets.

The authorized notification number is CN106480433B, which provides a fluid injection device, which has super-hydrophobic coating treatment on the flow channel, and can optionally design the valve stem as a stepped cylinder with reduced size from top to bottom, and the inlet conical surface The taper is designed to be 100-130°. By reducing the viscous resistance of the fluid along the flow direction, it makes it easier to spray medium and high viscosity fluids.

The authorized notification number is CN207357480U, which provides a split-type droplet distribution device. Figure 10 and Figure 12 show the two working states of the striker. The piezoelectric ceramic stack drives the striker to reciprocate up and down, between the striker and the nozzle. Instantaneous high pressure is generated to spray the fluid from the nozzle. In order to facilitate the injection of fluid with high viscosity, the equipment includes a preheating device.

The flow channel in the prior art only considers the flow of the fluid ejected from the nozzle, and does not consider the influence of the fluid flow inside the valve body on the valve performance. It is used to inject a small amount of high-viscosity fluid, especially when the viscosity is greater than 100,000mPa When the fluid is in a small amount of s, the outlet kinetic energy of the fluid beam is not enough, the fluid is not easy to be sheared, the injection is more difficult, and the single injection volume is not easy to control. In the prior art, methods such as heating the fluid and applying a super-hydrophobic coating to the flow channel make it easier for the fluid to be ejected from the nozzle, but the structure is complex and the durability is poor. Therefore, it is necessary to design an injection device with a simple structure and a long service life for injecting a small amount of high-viscosity fluid.

Contents of the invention

Aiming at problems such as insufficient injection kinetic energy (especially for high-viscosity fluid) and difficulty in controlling the single injection volume in the fluid injection device in the prior art, the present invention optimizes the design of the striker head and the nozzle structure of the fluid injection device. Conducive to micro-spraying of high-viscosity fluids.

The first aspect of the present invention provides a striker structure, the striker is a hammer striker, the radius of revolution of the hammer striker changes along the axis of rotation, the radius of revolution is larger at the head side of the striker, and The radius of gyration is small, the side with the larger radius is called the striker head, and the side with the smaller radius is called the striker shank. Preferably the radius of the head is 1.5-2.0 times the radius of the shank.

The second aspect of the present invention provides a striker head, the striker head is composed of a cross-section that pushes the fluid jet and a cylindrical surface that guides the fluid to discharge in the opposite direction, the cross-section of the push fluid jet is elliptical or similar to An elliptical cross-section, the length of the half-axis in the horizontal direction of the cross-section is greater than the length of the half-axis in the vertical direction.

A third aspect of the present invention provides a striker structure with a "groove/rib structure".

The grooves or ridges are one or a combination of rectangular, triangular, arc-shaped cross-sections. The groove or rib structure is a rotary groove or a rotary rib. The "groove/rib structure" is preferably designed as a revolving groove or a revolving rib with a rectangular, triangular, arc-shaped or other cross-section, that is, the grooves or ribs are distributed axisymmetrically along the axis of rotation. It can also be designed in the form of pits/bumps, through holes, blind holes, or a combination of several forms according to the working principle of the "groove/ridge structure".

Preferably, the depth of the "groove/rib structure" is 3% to 10% of the maximum diameter of the head of the hammer striker, particularly preferably 3% to 5%. The width of the groove/rib is 1 to 4 times, preferably 2 to 3 times, the depth of the groove/rib. Within the preferred range, the comprehensive effect is the best. If the width is too wide and the depth is too shallow, the secondary flow effect will not be obvious. Otherwise, the strength will be affected, and the gaps are not easy to clean.

Preferably, the total number of grooves/ribs is greater than or equal to 2, and the total number of grooves/ribs is particularly preferred to be greater than or equal to 3.

In order to avoid deposition of high-viscosity fluid, affect jetting performance after hardening and facilitate cleaning and maintenance of the striker, it is preferable to add Teflon or other non-stick material coating to the groove/ridge structure.

The fourth aspect of the present invention provides a hammerhead striker structure with a "groove/ridge structure".

The "groove/rib structure" can be arranged on the striker head, striker shank or both of the hammer head striker, preferably, on the striker head, especially preferably, a rectangular concave is arranged on the striker head. Grooves/ridges, dimples/bulbs arranged on the shank of the firing pin.

The fifth aspect of the present invention provides a nozzle structure, that is, the nozzle part of the flow channel is optimized from the straight circular tube nozzle structure in the prior art so that the diameter of the nozzle becomes smaller toward the outlet. The nozzle of the present invention has a structure in which the diameter gradually changes toward the outlet direction, the upstream part of the nozzle has a larger diameter, and the downstream part of the nozzle has a smaller diameter. The nozzle of the present invention can also be a circular tube with a gradually changing diameter or a tapered tube with a gradually changing diameter.

Further, the diameter gradient structure of the nozzle can be two steps. Preferably, a chamfer is used to transition between the first step and the secondary step to reduce local fluid resistance. Especially preferably, a chamfer is used between the first step and the secondary step. Round corner transition, the local fluid resistance of the round corner transition is the smallest.

Preferably, the fillet radius should be between 0.2 mm and 0.5 mm, and particularly preferably the fillet radius should be between 0.2 mm and 0.3 mm. In the preferred range, the fluid resistance is the least, the jetting is smoother, and it is not easy to be blocked.

Further, the gradual change structure of the nozzle part can also be more than 3 steps.

The sixth aspect of the present invention provides a conical spray chamber for fluid injection, a method for designing the cone angle of the conical section, the cone angle is represented by α, and when 60°<α<95° the jet valve sprays high-viscosity fluid, each Item performance is relatively balanced, preferably, 60°<α<90°, more preferably, 80°<α<90°

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

(1) The radius of gyration of the hammer head part of the hammer head striker is relatively increased, and the lower part has a larger gyration diameter, which can arrange a larger-sized striker head arc, which increases the interaction area with the fluid and increases the "effective fluid" The pressure gradient increases the kinetic energy of fluid injection, which is beneficial to the injection of high-viscosity fluid. The "hammer head" structure increases the kinetic energy of fluid injection, making it easier for the ejected fluid to be cut off, so the diameter of the nozzle can be made smaller without worrying about the difficulty of injection caused by the increase in resistance caused by too small a diameter of the nozzle. The individual fluid dots that can be sprayed are smaller in diameter than conventional technology.

(2) The beneficial effect of the elliptical cross-section of the striker head is to increase the pressure gradient in the jet channel and increase the kinetic energy of the jet fluid.

(3) The "groove/rib structure" increases the kinetic energy of the "effective fluid" through the "secondary flow" effect, and the structure is compact, and the effect of improving the kinetic energy of the jet is remarkable. When working, the change rate of fluid shear velocity increases, which is equivalent to reducing the local viscosity of high-viscosity fluid for shear-thinning fluid, which is beneficial to the injection of high-viscosity fluid.

(4) The surface area of the "hammer head" striker with "groove/rib structure" is larger than that of a simple cylinder-head striker, which is convenient for arranging more "groove/rib structures" for the same injection valve , On the premise of not changing the structure of the tail of the striker, only the "hammer head" part needs to be changed to change the injection performance, which improves the versatility of the parts of the injection valve. When working, the groove/ridge structure on the hammer head will agitate the fluid, reduce the viscosity of non-Newtonian fluid, and improve the jetting performance of high-viscosity fluid.

(5) The diameter of the upstream part of the nozzle is larger, which can reduce the flow resistance of the fluid. The diameter of the downstream part of the nozzle is smaller, which is used to form a smaller fluid beam, which is beneficial to control the single-point diameter of the fluid. The beneficial effect is that it can spray smaller The precise fluid beam can be sprayed accurately without excessive flow resistance, which will cause difficulty in spraying.

(6) The nozzle and the device of the present invention are mutually independent structures in the fluid injection device, and the optimization of the striker head structure and the nozzle structure can be implemented at the same time to achieve a better high-viscosity fluid injection effect.

Description of drawings

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Fig. 1 is a schematic diagram of the calculation principle of the pressurized fluid volume when the striker is lifted in Example 1 of the present invention

Figure 1a is a schematic diagram of the calculation principle of the pressurized fluid volume when the striker is lifted in Example 2 of the present invention

Figure 1b is a schematic diagram of the calculation principle of the pressurized fluid volume when the striker is lifted in Example 2 of the present invention

Fig. 2 is a schematic diagram of the calculation principle of the pressurized fluid volume when the striker falls in Example 1 of the present invention

Figure 2a is a schematic diagram of the calculation principle of the volume of the pressurized fluid when the striker falls in Example 2 of the present invention

Figure 2b is a schematic diagram of the calculation principle of the pressurized fluid volume when the striker falls in Example 2 of the present invention

Fig. 3 is a diagram of the relationship between the effective fluid volume change and the radius of the firing pin in Example 1 of the present invention

Fig. 4 is a diagram of the relationship between the effective fluid volume change and the stroke of the striker in Example 1 of the present invention

Fig. 5a is the comparison of the flow channel profile pressure contours of Example 1 and Example 2 of the present invention

Fig. 5b is the comparison of flow channel profile streamline diagrams of Example 1 and Example 2 of the present invention

Figure 6a is a schematic view of the cross-sectional structure of the flow path of the striker head (ordinary striker) of the example of the present invention

Fig. 6b is a schematic diagram of the cross-sectional structure of the flow path of the striker head (hammer striker) of the example of the present invention

Fig. 7a is a schematic diagram of partial details of the groove structure of Example 3 of the present invention

Figure 7b is a schematic diagram of local details of the rib structure of Example 3 of the present invention

Fig. 8 a is the local velocity vector diagram of groove structure fluid of the present invention example three

Fig. 8b is a nephogram of the change rate of local shear velocity of the fluted structure fluid in Example 3 of the present invention

Fig. 9 is a schematic diagram of the cross-sectional structure of the nozzle flow channel of Example 4 of the present invention

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings and design principles of flow path geometric parameters. However, the present invention should be understood as not limited to such embodiments described below, and the technical idea of the present invention can be implemented in combination with other known technologies or other technologies having the same functions as those known technologies.

Example 1: "Hammerhead" firing pin

As shown in Figure 6b, this embodiment provides a "hammer head" striker structure, the radius of revolution of the "hammer head" striker changes along the axis of rotation, like the head of a hammer, on the side of the impact fluid (that is, the side of the impact fluid in Figure 6b The firing pin head part) has a larger radius of gyration, while on the other side (that is, the firing pin rod part of Figure 6b), the gyration radius is smaller, and the radius of the head is between 1.5-2.0 times the radius of the rod. The side with the larger size is called the "hammer head" part. The structure of the "hammer head" striker in the present invention is shown in Figure 6b in comparison with the common striker head as shown in Figure 6a. The design principle is as follows:

Figure 1 and Figure 2 are the calculation principle diagrams of the "effective fluid" flow path of the injection valve with the head of the firing pin as a ball. When injecting, the firing pin moves vertically downward. The state of the firing pin of the injection device before impact is shown in Figure 1. In the figure, the space between the firing pin and the conical surface (hereinafter referred to as "cone") is filled with fluid, and the state after the impact of the firing pin is shown in Figure 2. During the impact, The state of fluid flow is shown in Figure 5b. When the striker hits the fluid, the fluid flows relative to the striker under the action of the pressure gradient. A part of the fluid is ejected from the nozzle along the direction of the striker, which is called "effective fluid", and the other part After the fluid is squeezed out by the firing pin, it flows back along the opposite direction of the firing pin movement, which is called "ineffective fluid". The volume change process of the "effective fluid" will be described below in conjunction with Fig. 1 .

Figure 1 shows the cross-sectional view of the flow channel of the injection valve with the head of the striker as a sphere passing through the axis of rotation. The cross-section of the striker head is an arc with a radius of R, and the cone angle of the two tapered walls is α (0°<α<180° , Figure 1 is the special case of α=90°), point o is the arc center of the firing pin head, point a is the intersection point of the conical wall (the nozzle is located at point a), point b is the intersection point of the rotary axis and the section line of the firing pin head , make a vertical line on the wall through point o, the vertical foot is p, the intersection point of the vertical line op and the intercept line of the striker head is q, the vertical line passing through point q is drawn to meet the wall surface at c, and the horizontal line passing through point q is drawn to meet the rotation axis at d, Then the length of the straight line qc is the striker stroke s, and the length of the straight line bd is the height H of the ball crown of the needle head. Taking the cross-section of the circular striker head shown in Figure 1 as an example, the relational formula is derived as follows:

The "effective fluid" volume is the volume of revolution of the quadrilateral bqpa around the axis of rotation oa, the volume of rotation of the triangle bdq around the axis of rotation oa is called "needle spherical cap", and the figure surrounded by three points of pqc is called "small triangle". . When the striker moves downwards, the volume of the "needle ball crown" remains unchanged, the area of the "small triangle" decreases, and the stroke s of the striker gradually decreases. When it reaches the limit position (Figure 2), the three points p, q, and c coincide, and the area of the small triangle is equal to 0.

The volume of "effective fluid" before impact (recorded as V _{effective fluid} ), can be calculated by subtracting the volume of the needle spherical cap (recorded as V _{needle spherical cap) from the volume of the polygon adqp revolving around the rotation axis (recorded as V adqp )} , where V _adqp is easy to calculate , the derivation process is omitted.

For a spherical striker head, a Cartesian coordinate system is established at point o in the center of the spherical cap, the horizontal axis is the x-axis, and the vertical axis is the y-axis, and the volume formula of the spherical cap of the needle head is calculated.

Formula 1:

In particular, when the wall cone angle α=90° in Figure 1, it can be deduced that:

Formula 2:

Calculate the volume of the remaining parts in the same way, and get the algebraic relationship between the "effective fluid" volume V effective fluid and the striker stroke s (or the arc radius R of the striker head) before impact:

Formula 3: V _{effective fluid} = a ₁ s ³ +b ₁ s ² +c ₁ s+d ₁

Formula 3': V _{effective fluid} = a ₂ R ³ +b ₂ R ² +c ₂ R+d ₂

Specially, when the wall cone angle α=90°

The calculation formula of the "effective fluid" volumetric amount ΔV effective fluid before and after the impact is:

Formula 4: ΔV _{effective fluid} = a ₃ R ³ +b ₃ R ² +c ₃ R+d ₃

Formula 4': ΔV _{effective fluid} = a ₄ s ³ +b ₄ s ² +c ₄ s+d ₄

a ₃ =0,

Specially, when the wall cone angle α=90°

a ₃ =0,

d₄＝0

d ₄ =0

Deriving both sides of formula 4 with respect to α gives:

Formula 5:

Wherein Formula 2 is a special form of Formula 1, Formula 3 and Formula 3' are different expressions of the same formula, and Formula 4 and Formula 4' are different expressions of the same formula.

According to Formula 4, the function curve shown in Figure 3 is obtained with the radius R of the striker as an independent variable. The curve of the dotted line + hollow circle in the figure is the stroke of the striker s = 0.1mm, and the curve of the solid line + solid circle is the stroke of the striker s = 0.2mm .

According to formula 4', the function curve shown in Figure 4 is obtained with the striker stroke s as an independent variable. The curve of the dotted line + hollow circle in the figure is the radius of the striker R = 2mm, and the curve of the solid line + solid circle is the radius of the striker R = 3mm. From the change trend of the two curves in Figure 4, it can be seen that the change in effective fluid volume is positively correlated with the stroke of the striker, that is, the greater the stroke of the striker (or the lift height of the striker), the greater the change in effective fluid volume, and the easier it is to spray. Comparing the difference between the coordinate points of the two curves, it can be seen that the change in effective fluid volume is positively correlated with the radius R of the firing pin, that is, the larger the radius of the firing pin, the greater the change in effective fluid volume, and the easier it is to spray.

Figure 3 and Figure 4 show only two curves with different parameters, and similarly, a family of curves with different parameters can be made according to the above formula.

According to formula 4, compared with the curve shown in Figure 3, the "effective fluid" volume change ΔV effective fluid increases monotonously with the radius R of the striker, that is, increasing the radius of the striker in the same space can improve the ejection capacity of the valve body, according to For the conventional striker structure shown in Figure 6a, this principle increases the radius of the striker head to obtain the "hammer head" striker structure shown in Figure 6b.

It is easy to get from formula 5, when α=0°, the ΔV effective fluid takes the maximum value, and the ΔV effective fluid increases monotonously with α, and when α=90°, the change rate of ΔV effective fluid is the largest, in order to make the jet valve spray high When viscous fluids are used, the properties are relatively balanced, and α is designed to be a smaller value near 90°, preferably 60°<α<90°, and particularly preferably 80°<α<90°.

The "hammer head" striker structure improves the pressure gradient of the fluid in the nozzle, increases the outlet velocity of the fluid, and is more effective when used to spray high-viscosity fluid.

Embodiment 2: Oval hammer head striker

Fig. 1a, Fig. 2a, Fig. 1b, Fig. 2b are schematic diagrams for calculating the "effective fluid" of the flow channel of the injection valve with the head of the striker as an ellipsoid. As shown in Figure 1a and Figure 2a, the length of the transverse semi-axis of the elliptical section is greater than the length of the longitudinal semi-axis; as shown in Figure 1b and Figure 2b, the length of the transverse semi-axis of the elliptical section is smaller than the length of the longitudinal semi-axis. Since Figure 1 (the head of the striker is a sphere) can be considered as a special form of Figure 1a (the head of the striker is an ellipsoid), the design principle is the same as that of the above-mentioned spherical section, the difference is that the semi-axis parameter is added, and the specific design process is as follows:

Figure 1a shows the cross-sectional view of the flow channel of the injection valve with the head of the striker as an ellipsoid passing through the axis of rotation. The cross-section of the striker head is an ellipse. The cone angle is α, the slope of the conical wall line on the right is k, and the right conical wall line is moved parallel to the ellipse, the tangent point is point q, and the coordinate of point q is q(x0, y0), passing through q Point to make the vertical segment qp of the conical wall, and the vertical foot is p.

Define the length of the semi-axis in the horizontal direction of the ellipse as a, and the length of the semi-axis in the vertical direction as b, then the functional relationship of the ellipse can be expressed in the Cartesian coordinate system as:

Formula 6:

Applying the derivation rule of implicit function, deriving and simplifying both sides of the elliptic equation, the slope formula of the conical wall can be expressed as:

Formula 7:

Simultaneous formula 6 and formula 7 can be solved, and the coordinate q(x0, y0) of point q can be expressed as:

In particular, when the cone angle α=90°, the slope k=1, and the coordinate q(x0,y0) of point q can be expressed as:

The volume of revolution of the needle ellipsoidal crown is:

Formula 8:

Put the coordinate q(x0,y0) of point q into formula 8 to get:

Formula 9:

In particular, when a=b, formula 9 and formula 2 are equivalent, that is

Regarding the "effective fluid" volume change ΔV, the effective fluid can be organized into the format shown in Formula 4 according to the calculation principle of the embodiment of the present invention, where the variables are s, a, and b, which will not be repeated here. According to the calculation method of the "effective fluid" volume change ΔV in Example 1, it is easy to obtain that when the ratio of a and b is larger, the ΔV is larger, that is, when the elliptical section striker with a longer semi-axis in the horizontal direction is used, the ΔV is more Larger, the pressure gradient in the injection channel is also greater, and the kinetic energy of the injected fluid is greater.

Figure 5a is a comparison of the pressure cloud diagrams of the jet flow channel section of the striker jet obtained by using the flow field simulation calculation software. Except for the different cross-sections of the striker head, the rest of the geometric parameters are the same. Longer oval cross-section striker, oval cross-section striker with longer vertical semi-axis. From the comparison of the pressure contours, it can be seen that when other parameters are the same, the pressure gradient in the injection channel is the largest when the elliptical cross-section striker with a longer semi-axis in the horizontal direction is used, so the kinetic energy of the injected fluid is the largest.

Figure 5b is a comparison of streamline diagrams of the striker jet flow path profile obtained by using the flow field simulation calculation software. The "effective fluid" flows downward along the nozzle, and the "ineffective fluid" flows upward.

This embodiment is a specific description of a typical embodiment of the method for calculating the "effective fluid" volume. In actual use, any striker head with a defined function curve can be calculated according to the calculation principle of the embodiment. That is, the striker head of the present invention can also be not elliptical but any curve, as long as according to the principle of the present invention, the interface shape is designed to be similar to an elliptical structure, wherein the semi-axis length of the ellipse along the horizontal direction is longer than that of the ellipse along the vertical direction. The semi-axis length of the direction is longer.

Example 3: Hammerhead striker with "groove/ridge structure"

Figure 7a and Figure 7b are partial schematic diagrams of the striker head of this embodiment, showing several typical striker head structures, and the striker head is designed with grooves/ridges, pits/bumps, round holes or one of the above structures. one or several combinations.

The working principle of the "groove/rib structure" in the present invention is that when the striker moves downward, most of the "ineffective fluid" flows in the opposite direction of the striker movement and becomes the "main flow". The fluid near the "structure" is driven to flow by the firing pin and becomes the "secondary flow". Since the direction of the "secondary flow" is opposite to that of the "main flow", the flow channel of the "main flow" is squeezed out, and the flow area of the main flow is reduced, thereby indirectly The increased kinetic energy of the "effective fluid". High-viscosity fluids are generally high-molecular fluids with shear thinning effects. When such fluids are sprayed, the "groove/ridge structure" increases the local shear rate of the fluid, thereby reducing the apparent viscosity of the fluid and increasing the viscosity of the fluid. The fluidity increases the exit kinetic energy of the fluid beam at the nozzle, which is beneficial to the fluid injection, and the effect is better.

Figure 8a shows the flow trend of "ineffective fluid" at a certain moment when the striker falls, and the velocity vector line in the figure is the "groove/ridge structure" of the local fluid near the striker head "groove/ridge structure" calculated by the flow field simulation calculation software. "Secondary flow", from the partial enlarged view, it can be seen that there are obvious "secondary flows" on both sides of the "groove/ridge structure", which reduces the width of the flow channel of the "main flow".

Figure 8b shows the contrast relationship between the changes in the local shear velocity cloud map of the fluid near the groove before and after adding the "groove/ridge structure". The left picture is before the groove is added, and the right picture is after the groove is added. Yes, after adding the "groove/ridge structure", the rate of change of fluid shear velocity increases. For shear-thinning fluids, it is equivalent to reducing the local viscosity of high-viscosity fluids, which is beneficial to fluid injection.

Embodiment 4: Round tube nozzle with gradual diameter change

As shown in FIG. 9 , this embodiment provides a nozzle optimization structure, that is, the nozzle part of the flow channel is optimized from a straight circular tube nozzle structure in the prior art to a circular tube nozzle with a gradually changing diameter. The upstream part of the nozzle has a larger diameter and the downstream part of the nozzle has a smaller diameter. The nozzle part is designed according to the principle of minimum local fluid loss, so that the change of flow path can be evenly transitioned.

Preferably, the diameter gradient structure of the nozzle is two steps, and the transition between the first step and the secondary step is preferably chamfered to reduce local fluid resistance, and it is especially preferred to use rounded corners between the first step and the secondary step transition.

Preferably, the fillet radius should be equal to between 0.2 and 0.5, and a particularly preferred fillet radius should be equal to between 0.2 and 0.3.

Claims (18)

1. The striker for fluid ejection is characterized in that the striker is a hammer head striker, the gyration radius of the hammer head striker is changed along a gyration shaft, and the gyration radius of a striker head part is larger than that of a striker rod part.

2. The firing pin for fluid ejection according to claim 1, wherein the radius of gyration of the firing pin head portion is 1.5 to 2.0 times the radius of gyration of the firing pin shaft portion.

3. The firing pin for fluid injection according to claim 1, wherein the firing pin head portion is formed of a cross section of the pushing fluid injection which is an elliptical cross section or a cross section similar to an elliptical cross section and a cylindrical surface which guides the fluid to be discharged in the opposite direction, and a length of a half axis in a horizontal direction of the cross section is larger than a length of a half axis in a vertical direction.

4. The firing pin for fluid ejection according to claim 1, wherein the firing pin is provided with a groove or rib structure.

5. The firing pin for fluid ejection according to claim 4, wherein the depth of the groove or the ridge structure is 3% to 10% of the maximum diameter of the head striking head portion.

6. A plunger for fluid ejection, wherein said plunger is provided with a groove or rib structure.

7. The firing pin for fluid ejection according to claim 4 or 6, wherein the groove or rib structure is a rotary groove or rotary rib.

8. The striker for fluid ejection according to claim 4 or 6, wherein the total number of the grooves or the ridges is 3 or more.

9. The striker for fluid ejection according to claim 4 or 6, characterized in that the width of the groove or rib is 1 to 4 times the depth of the groove or rib.

10. The striker for fluid ejection according to claim 4 or 6, characterized in that the width of the groove or rib is 2 to 3 times the depth of the groove or rib.

11. A nozzle for fluid ejection, characterized in that the nozzle has a structure in which the diameter gradually changes toward the outlet, the diameter of the upstream portion of the nozzle is larger, and the diameter of the downstream portion of the nozzle is smaller.

12. The nozzle according to claim 11, wherein the diameter-gradually-changing structure of the nozzle is a two-step structure.

13. The nozzle of claim 12, wherein the two steps are rounded or chamfered.

14. The nozzle of claim 13, wherein the fillet radius is equal to any value between 0.2mm and 0.5 mm.

15. A conical spray chamber for spraying a fluid, characterized in that the conical section of the conical spray chamber has a cone angle of any value between 60 DEG and 95 deg.

16. A fluid ejection device comprising a striker, an ejection chamber, and a nozzle, wherein the striker is the striker for fluid ejection or the striker head for fluid ejection according to any one of claims 1 to 10.

17. A fluid ejection device as in claim 16, wherein the nozzle is the fluid ejection nozzle as in any one of claims 11 to 14.

18. The fluid ejection device of claim 16, wherein the ejection chamber is the conical ejection chamber for fluid ejection of claim 15.

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