CN103437235B - Hydraulic visualized isobaric step diffuser headbox for experimental headbox - Google Patents

Abstract

The invention discloses a visual isobaric square cone tube slurry distributor for a hydraulic experimental headbox, which is mainly composed of two plexiglass PMMA plates, and the seal between the two plexiglass PMMA plates adopts a concave-convex surface Or tongue and groove sealing form, one of the plexiglass PMMA plates is provided with a dilution water injection port; after the two plexiglass PMMA plates are combined, a connected hollow cavity and a main flow channel are formed inside, and the static pressure of each point in the main flow channel Equal; the hollow cavity is composed of two plexiglass PMMA plates extending along the respective lengths of the cavity, the two ends of which are respectively provided with a slurry inlet and a slurry return port, and the hollow cavity is from the slurry inlet to the slurry return port. The direction gradually narrows; the main flow channel is composed of grooves extending along the respective width directions on two plexiglass PMMA plates. The entrance is connected. The invention can conveniently carry out the measurement and visualization research of the flow field, and has good sealing performance and convenient disassembly.

Description

A visual isobaric square cone tube slurry distributor for hydraulic experimental headbox

technical field

The invention relates to the technical field of a hydraulic experimental headbox, in particular to a visual isobaric square cone tube slurry distributor for a hydraulic experimental headbox.

Background technique

It is known in the industry that the square cone tube pulp distributor is one of the key components of the hydraulic headbox. In order to realize the equal pressure distribution of pulp, domestic and foreign researchers have carried out relevant research on this and obtained many important scientific researches. results.

At home, a kind of multi-tube pulp distributing device for rotary screen paper machine of Anhui Provincial Papermaking Company is composed of a hole tube body, a pulp distribution cover, a square cone tube, a lip plate and a support. The paper machine square cone tube pulp distributor of Fujian Xiyuan Paper Co., Ltd. has a hollow cavity, a pulp inlet and a pulp return port, and the pulp outlets are evenly distributed along the length direction on the outside, and the cross section is self-inlet. The pulp mouth gradually narrows towards the pulp mouth. The square cone tube pulp distributor of Tianjin Tianqing Paper Machinery Co., Ltd. is a square cone shape formed by connecting two right-angled trapezoidal plates through a connecting plate connecting the oblique waists of the two right-angled trapezoidal plates. The two right-angled trapezoidal plates are respectively equipped with Connecting flanges, each right-angled trapezoidal connecting plate is connected to the pipe box through the connecting flange, and a plurality of grouting pipe holes are arranged inside the pipe box. The complementary dispenser invented by Liu Wei of South China University of Technology and others: it is composed of two square cone tube pulp distributors stacked up and down in a complementary manner. It is symmetrical from left to right and not connected to each other. The non-uniform distribution of slurry realizes the complementarity of the slurry mass flow rate of the two square cone headers and their corresponding branch tube bundles. In addition, the isobaric pulp distributor of Liu Jian'an of South China University of Technology is mainly composed of inlet flange, damping element, cylinder body, outlet joint, cylinder cover and overflow port, and is mainly suitable for fourdrinier paper machines.

In the world, there are several influential companies in the development of dilution water concentration headbox technology, such as Beloit (metso) company, Voith company, Valmet (metso) company, and EsherWyss, Vaahto, Brandes&Heneze Gmbh, G&Lv company, PMPOLAND company in Poland, etc., its typical square-conical pulp distributor products mainly include conical and square-conical pulp distributors, the structures are similar, and they are all designed and processed according to the principle of equal pressure, which significantly improves the quality of the paper. product quality. These conical isobaric distributors have a return flow system and its viewing transparent tube. In the backflow system, the backflow valve is used to control the backflow of pulp to ensure a consistent pulp flow velocity, and the opening of the backflow valve is determined by observing the pulp flow in the transparent tube.

Although there are many square cone tube slurry distributors researched at home and abroad, and these square cone tube slurry distributors can play a great role in engineering practice, none of these square cone tube slurry distributors can meet the flow field measurement requirements of the slurry distributor. requirements, the flow field cannot be visualized. At present, at home and abroad, there is no square cone tube slurry distributor that meets the requirements of PIV (Particle Image Velocimetry) and other measurement systems for measurement and visualization research. Based on this, the square cone tube slurry distributor of the present invention is suitable for engineering On the basis of practice, the flow field at various vehicle speeds can be measured and visualized, so that a theoretical breakthrough can be made in the flow field structure of the square cone tube slurry distributor, which can have a good guiding role in engineering practice.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art, to provide a visual isobaric square-cone tube slurry distributor for a hydraulic experimental headbox that can be used for flow field measurement and visualization research, so that the square-cone tube slurry distributor The theoretical breakthrough of the flow field structure can have a good guiding effect on engineering practice.

In order to achieve the above object, the technical solution provided by the present invention is: a visual isobaric square cone tube slurry distributor for a hydraulic experimental headbox, which is mainly composed of two paired organic glass PMMA plates. The seal between the two plexiglass PMMA plates is in the form of a concave-convex surface or a tenon-groove seal. One of the plexiglass PMMA plates is provided with a dilution water injection port; The hollow cavity on the end face and the main flow channel running through one side of it, the main flow channel is connected with the hollow cavity, and the static pressure at each point in it is equal; the hollow cavity is composed of two plexiglass PMMA plates along the The cavities extending in the respective length directions are combined, and its two ends are respectively provided with a slurry inlet and a slurry return port, and the hollow cavity gradually shrinks from the slurry inlet to the slurry return port, forming a square cone-shaped structure; The main flow channel is composed of grooves extending along the respective width directions on two plexiglass PMMA plates. The injection port is connected.

After the two plexiglass PMMA plates are combined, they are pressed together by a clamping block to be fixed as a whole.

After the two plexiglass PMMA plates are combined, the two end surfaces penetrated by the hollow cavity are correspondingly connected to the slurry inlet connection plate with the slurry inlet tube and the return flow end connection plate with the return tube through respective clamping blocks, and The slurry inlet pipe communicates with the slurry inlet port, and the return pipe communicates with the slurry return port.

After the two plexiglass PMMA plates are combined, a concave surface for sealing and a threaded hole for connection are provided on the side that is penetrated by the main flow channel.

The main flow channel is a cylindrical flow channel, and the groove on each plexiglass PMMA plate is a semi-cylindrical groove.

A gasket is sandwiched between the two plexiglass PMMA plates.

Gaskets are sandwiched between the connecting plate at the slurry inlet end, the connecting plate at the return end and the two combined organic glass PMMA plates.

The gasket is an asbestos rubber gasket.

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

1. It is applicable to flow field measurement systems such as PIV (particle image velocimetry) particle image velocity meter for measurement and visualization research, which can clearly reflect the flow channel and flow field of the square cone tube slurry distributor, and the characteristics of the square cone tube slurry distributor Velocity-related parameters including velocity, vorticity, turbulent kinetic energy, and dissipation rate can be easily measured and studied.

2. This visualized isobaric square cone slurry distributor has small body, simple structure, good sealing performance, convenient disassembly and low cost, and can be used for fluid experiments before engineering practice.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Fig. 2 is a view along the direction A of Fig. 1 .

Fig. 3 is a view taken along direction B of Fig. 1 .

Fig. 4 is a view from the direction C of Fig. 1 .

Fig. 5 is a side view of one of the plexiglass PMMA plates of the present invention.

Fig. 6 is a side view of another plexiglass PMMA plate of the present invention.

Fig. 7 is a schematic diagram of the flow field measurement and visualization research of the visualized isobaric square cone slurry distributor using the PIV measurement system.

Fig. 8 is the original image in the turbulent flow process of PIV measurement and visualization of isobaric square cone slurry distributor.

Fig. 9 is the original image in the vortex process of PIV measurement visualization isobaric square cone slurry distributor.

Fig. 10 is the visualized turbulent streamline of the isobaric square cone slurry distributor after image analysis and processing.

Fig. 11 is the visualized vortex streamline of the isobaric square cone slurry distributor after image analysis and processing.

Detailed ways

The present invention will be further described below in conjunction with specific examples.

Referring to Fig. 1 to Fig. 6, the visual isobaric square cone tube slurry distributor for the hydraulic experimental headbox described in this embodiment is mainly composed of two paired organic glass PMMA plates 1, 2. , the rear wall is composed of a quadratic curve, the seal between the two plexiglass PMMA plates 1 and 2 adopts a concave-convex surface or a tongue-and-groove seal, and one of the plexiglass PMMA plates is provided with a dilution water injection port 5 ( The dilution water injection port 5 is usually set on the machine glass PMMA plate located above), and the dilution water is injected into the dilution water injection port 5 to adjust the banner quantitative of the pulp fluid in the square cone tube pulper to ensure that the pulp fluid Evenly distributed in the lateral direction; after the two plexiglass PMMA plates 1 and 2 are combined, they are compressed by the clamping block 6 to form a whole, and a hollow cavity 3 penetrating through its two ends and a hollow cavity 3 penetrating one of them are formed inside. The main flow channel 4 on the side, the main flow channel 4 communicates with the hollow cavity 3, and the static pressure of each point in it is equal (designed according to the principle of equal static pressure at each point of the flow field); the hollow cavity 3 is composed of Two plexiglass PMMA plates 1 and 2 are formed by the cavity extending along the respective length directions, and the two ends are respectively provided with a slurry inlet 301 and a slurry return port 302, and the hollow cavity 3 is formed from the slurry inlet 301 Gradually shrink towards the direction of the return port 302, forming a square cone-shaped structure; the main flow channel 4 is a cylindrical flow channel, which is composed of two plexiglass PMMA plates 1,2 extending along the respective width direction of the semi-cylindrical In the present embodiment, seven cylindrical runners are arranged at equal intervals along the length direction of the plexiglass PMMA plate, and communicate with corresponding dilution water injection ports 5 respectively, and the dilution water injection ports The number of 5 is consistent with the number of cylindrical runners.

In addition, in order to facilitate the connection with external components, after the two plexiglass PMMA plates 1 and 2 described in this embodiment are combined, the two end faces penetrated by the hollow cavity 3 are connected through the respective clamping blocks 12 to carry out the corresponding connection. The slurry inlet end connection plate 7 of the slurry pipe 701 and the return end connection plate 8 with a return pipe 801, and the slurry inlet pipe 701 communicates with the slurry inlet 301, the return pipe 801 communicates with the slurry return port 302, and the slurry inlet The pipe 701 and the return pipe 801 can be easily connected with external components, and in practical application, considering the problem of anti-corrosion, the connecting plate 7 of the feeding end described in this embodiment, the feeding pipe 701 and the returning end are connected Plate 8 and return pipe 801 are all made of stainless steel; meanwhile, in order to facilitate the connection of this visualized isobaric square cone slurry distributor and the next part of the hydraulic experimental headbox, the two pieces of plexiglass described in this embodiment After the PMMA plates 1 and 2 are combined, the side surface through which the main flow channel 4 penetrates is provided with a concave surface 9 for sealing and a plurality of threaded holes 10 for connection, so as to facilitate the use of bolts to connect the concave-convex sealing surface with the parts behind. In order to save costs and strengthen sealing, asbestos rubber gasket 11 is sandwiched between the two plexiglass PMMA plates 1 and 2 described in the present embodiment. Asbestos rubber gaskets 13 are also sandwiched between the combined two plexiglass PMMA plates 1 and 2 .

In addition, in this embodiment, the PIV measurement system is used to conduct flow field measurement and visualization research on the visualized isobaric square cone slurry distributor, and its measurement installation is shown in Figure 7. The generated sheet light and CCD are perpendicular to each other, and the sheet light and CCD generated by the laser need to be constantly moved to adjust and measure for different parts. The circulating water tank is filled with less than 0.01% pulp, and the pulp is fed from the pulp through the pulp input pump. The pipe 701 enters the pulp inlet 301 of the visualized isobaric square cone tube pulp distributor, and then enters the mainstream flow channel 4 of the visualized isobaric square cone tube pulp distributor, and then the main flow of pulp enters the hydraulic experimental headbox through the main flow channel 4 The next part, and a small part of the return flow flows out from the return port 302 of the visible isobaric square cone pulp distributor, and enters the pulp circulation pipeline through the return pipe 801, thereby forming a circulation of the pulp flow. When working, the flow field of the visualized isobaric tube slurry distributor is photographed and measured, and then the image is analyzed and processed to obtain the original image of the visualized isobaric tube slurry distributor in the process of turbulence and eddy flow. Specifically, as shown in Figure 8 and Figure 9, the turbulent streamline and vortex streamline of the visualized isobaric square cone slurry distributor after image analysis and processing can be obtained, as shown in Figure 10 and Figure 11 in detail. Of course, with this system, we can also conduct other flow field measurement and visualization studies of the square cone slurry distributor.

In a word, after adopting the above scheme, the present invention can measure and visualize the flow field at various vehicle speeds on the basis of conforming to engineering practice, so that the flow field structure of the square cone tube slurry distributor can obtain a theoretical breakthrough , can have a good guiding role in engineering practice. Compared with the prior art, the present invention has the advantages of small body, simple structure, good sealing performance, convenient disassembly, low cost, etc. It is an ideal square tapered tube slurry distributor and is worth popularizing.

The implementation examples described above are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Therefore, all changes made according to the shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims (8)

1. the visual isobaric step diffuser headbox of a hydraulic experiment head box, it is characterized in that: described visual isobaric step diffuser headbox is combined into primarily of two pieces of lucite PMMA plates (1,2) of pairing, sealing between these two pieces of lucite PMMA plates (1,2) adopts male and fomale(M&F) or tongue-and-groove seal form, and wherein one block of lucite PMMA plate is provided with dilution water inlet (5); After described two pieces of lucite PMMA plates (1,2) combine, inside is formed with the hollow cavity (3) running through its both ends of the surface and the main flow runner (4) running through one side, this main flow runner (4) is communicated with hollow cavity (3), and the static pressure of this main flow runner (4) interior each point is equal; Described hollow cavity (3) is combined by the die cavity extended along respective length direction on two pieces of lucite PMMA plates (1,2), its two ends are respectively equipped with stock inlet (301) and overfall mouth (302), and this hollow cavity (3) reduces to the direction of overfall mouth (302) gradually from stock inlet (301), the side's of being formed cone structure; Described main flow runner (4) is formed by the groove combination extended along respective width on two pieces of lucite PMMA plates (1,2), and this main flow runner (4) has many length directions along lucite PMMA plate to be spaced, and be communicated with corresponding dilution water inlet (5) respectively.

2. the visual isobaric step diffuser headbox of a kind of hydraulic experiment head box according to claim 1, be is characterized in that: after described two pieces of lucite PMMA plates (1,2) combine, compressed by clamp, admittedly be an entirety.

3. the visual isobaric step diffuser headbox of a kind of hydraulic experiment head box according to claim 1, it is characterized in that: after described two pieces of lucite PMMA plates (1,2) combine, the slurry that enters that its both ends of the surface run through by hollow cavity (3) connect with pulp-inlet pipe (701) through respective clamp correspondence holds connecting plate (7) and the backflow end connecting plate (8) with return duct (801), and this pulp-inlet pipe (701) is communicated with stock inlet (301), this return duct (801) is communicated with overfall mouth (302).

4. the visual isobaric step diffuser headbox of a kind of hydraulic experiment head box according to claim 1, it is characterized in that: after described two pieces of lucite PMMA plates (1,2) combine, its side run through by main flow runner (4) be provided with sealing with concave surface (9) and the screwed hole (10) that connects.

5. the visual isobaric step diffuser headbox of a kind of hydraulic experiment head box according to claim 1, it is characterized in that: described main flow runner (4) is cylindrical flow, and the groove on every block lucite PMMA plate is semi-cylindrical recesses.

6. the visual isobaric step diffuser headbox of a kind of hydraulic experiment head box according to claim 1, is characterized in that: between described two pieces of lucite PMMA plates (1,2), pad has packing ring.

7. the visual isobaric step diffuser headbox of a kind of hydraulic experiment head box according to claim 3, is characterized in that: described in enter slurry end connecting plate (7) and backflow end connecting plate (8) and combination after two pieces of lucite PMMA plates (1,2) between respectively pad have packing ring.

8. the visual isobaric step diffuser headbox of a kind of hydraulic experiment head box according to claim 6 or 7, is characterized in that: described packing ring is asbestos rubber packing ring.