CN210085927U - Steam box adopting circulating steam - Google Patents

Abstract

The utility model discloses a steam box adopting circulating steam, which comprises an outer box body, an inner box body, a steam main pipe, a steam circulating pipe, a steam inlet main pipe and a steam branch pipe, wherein a uniflow type box body preheating chamber communicated with one side is formed between the outer box body and the inner box body; the bottom of the inner box body is distributed with steam injection pipes. The paper moisture adjusting method is that steam from a steam main pipe enters a box body preheating chamber to preheat an inner box body and a steam jet pipe; and the steam discharged after preheating enters the inner box body again and is sprayed to the surface of the paper through the steam spraying pipe. The steam box has the advantages of simple structure and low energy consumption, and can effectively prevent the phenomenon that the surface quality of paper is influenced due to the dropping of condensed water.

Description

Steam box adopting circulating steam

Technical Field

The utility model relates to a pulping and papermaking technical field, in particular to a steam box adopting circulating steam.

Background

In the drying part of the paper machine and the equipment such as calender, steam is sprayed along the paper cross-web, the steam is condensed in the paper and releases latent heat, thereby improving the drying capacity of the drying cylinder part, adjusting the uniformity of the moisture content of the paper cross-web, improving the printing performance of the calendered paper and the coating performance of the coated paper, and the cross-web uniformity of the printing performance, therefore, the steam box is widely applied to the paper machine of various high-grade papers, especially to special paper machines, such as decorative base paper.

It is important that the steam sprayed from the steam box is kept away from the water droplets which otherwise would cause sheet defects on the paper, and on the other hand, steam boxes used in the dryer section and in the calender are used in order to adjust the moisture content of the paper, so that the moisture content of the steam is relatively high and saturated steam is usually used which condenses to form water droplets when it hits objects at a somewhat lower temperature.

In the production process of a factory, due to the influence of factors such as overhaul or accidents, the paper machine does not continuously run, when the paper machine is started up after shutdown, the temperature of the steam box is obviously lower than that of saturated steam, and therefore when the paper machine starts to run, condensed water formed after steam condensation can be sprayed out from the nozzles in first-wave steam. In addition, because steam does not contain water drops, even during continuous operation, water drops may enter the steam box, and therefore a good method for preventing the water drops from falling on paper and a matched structure are needed on the steam box.

The traditional solution is to install a series of condensed water discharge devices at the lower part of the nozzle.

As disclosed in the patent applications US3795578 and US3726757, the solution is to use a wavy bottom plate, the nozzle is located at the highest point of the wave shape, and the trough is used for drainage, but this method does not solve the problem of condensate water generated at the time of starting up, and even if the condensate water generated at other positions is drained through the trough, the condensate water is still generated in the nozzle, and the wavy bottom plate is troublesome to manufacture. US3574338 has a steam box with a steam inlet in the bottom plate, wherein the steam inlet is higher than the bottom plate, but the top end of the steam inlet is flat, and the condensate from the top surface flows into the nozzles, and this method does not solve the problem of condensate from the start-up, and the cooled steam inlet provides opportunity for condensate formation.

Another solution is provided in patent application publication US5211813, in which the steam box comprises a plurality of steam chambers, and in addition to the pre-heated steam chamber, the steam from the header pipe is passed through a plurality of steam chambers, where the condensed water is filtered layer by layer and sprayed onto the paper, so that the steam sprayed onto the paper does not contain condensed water, which, although effective, is very complicated and expensive to manufacture and maintain.

In present steam chest design, in order to prevent the formation of condensate water in the steam chest and drip on the paper, can set up the steam house steward on the steam chest usually to set up parallelly connected steam branch pipe and preheating branch pipe on the steam house steward, utilize preheating branch pipe to preheat the steam chest earlier, close after preheating and accomplish and reduce or close preheating steam pipe, reuse steam branch pipe to carry steam in the steam chest, spout to the paper through the steam injection pipe in the steam chest at last. Although the steam box with the structure has a certain effect, in practical application, firstly, because the steam for preheating and injection directly comes from the steam main pipe, the steam heat utilization rate is low, the energy consumption is high, the production cost is high, and the steam box is not environment-friendly; secondly, the flow of preheated steam is reduced in the spraying process, the temperature of a steam box cannot be guaranteed to be not lower than the temperature of the steam sprayed to the paper all the time, so that condensed water is easy to generate, and the condensed water cannot be completely prevented from dripping; thirdly, steam is sprayed to paper sheets through holes in the steam distribution plate, condensed water formed in the distribution plate is easily brought to paper surfaces by the steam, a plurality of improved designs adopt the injection pipes to inject the steam, the injection pipes are higher than the steam distribution plate, the condensed water formed in the distribution plate is difficult to enter the paper through the injection pipes, but the inner holes of the injection pipes are of a cylindrical structure, the speed of the steam before and after entering the steam injection pipes is the same, the speed difference cannot be formed, the condensed water brought into the injection pipes by the steam cannot be damaged, the condensed water is also easily formed on the inner walls of the injection pipes, and therefore the injection effect and the quality of the.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome prior art not enough, provide an adopt steam chest of circulating steam, this steam chest simple structure, energy consumption are lower, can effectively prevent to drip because of the comdenstion water simultaneously and influence the phenomenon of paper quality.

The technical scheme of the utility model is that: a steam box adopting circulating steam comprises an outer box body, an inner box body, a steam main pipe, a steam circulating pipe, a steam inlet main pipe and a steam branch pipe, wherein a one-way flow type box body preheating chamber communicated at one side is formed between the outer box body and the inner box body; the bottom of the inner box body is distributed with steam injection pipes. In the structure, an inner box body is surrounded by an outer box body, and a box body preheating chamber formed between the inner box body and the outer box body preheats and preserves heat of a space in the inner box body; the box body preheating chamber is designed to be a one-way flow type structure with only one side communicated, so that steam in the box body preheating chamber gradually flows along the flow channel, and uniform preheating is ensured. The steam from the steam main pipe is used for preheating and then used for spraying, on one hand, the heat of the steam can be fully utilized, energy loss is reduced, on the other hand, along with continuous input of the steam, the temperature outside the inner box body is always slightly higher than the temperature inside the inner box body, and the formation of condensed water drops can be effectively prevented.

In the box body preheating chamber, the cross section along the steam flowing direction is in a rectangular ring shape, and the middle parts of one side and the other side of two opposite sides of the rectangular ring are separated, and the middle parts of the other side are communicated; in one side of the middle partition, a preheating inlet and a preheating outlet are respectively arranged on two sides of the partition. In fact, in the three-dimensional structure of the preheating chamber of the box body, three sides of the middle partition are arranged through the following first bottom plate, and only one side of the middle partition is communicated with the other side of the middle partition.

In order to facilitate equipment installation, one side of the middle partition in the box body preheating chamber is a vertical side, the preheating inlet is positioned above the partition, and the preheating outlet is positioned below the partition.

The bottom of the inner box body is provided with a first bottom plate, the bottom of the outer box body is provided with a second bottom plate, and the second bottom plate is positioned below the first bottom plate;

on one side of the partition in the middle of the box preheating chamber, the first bottom plate extends outwards from the inner box to the outer box, and the extending part of the first bottom plate forms a partition structure (similarly, the other two sides also extend outwards from the first bottom plate to the outer box to form partition structures); and a preheating outlet is formed between the first bottom plate and the second bottom plate and is positioned below the partition structure. In the structure, the other side of the first bottom plate opposite to the partition structure can adopt one of the following structural forms, and the steam is ensured to pass through: (1) the first bottom plate does not extend outwards and is connected with the bottom of the inner box body; (2) the first bottom plate extends outwards to be connected with the outer box body, but a larger long hole is formed in the connection part for steam to pass through; (3) the first bottom plate extends outwards to be connected with the outer box body, but a plurality of small holes are formed in the connection position for steam to pass through. The steam main pipe and the steam circulating pipe are arranged on the same side of the outer box body, steam flows in a single direction along the channel after entering the box body preheating chamber and is finally discharged from the steam circulating pipe, so that the full utilization of the steam can be ensured, all parts of the inner box body are fully heated, and the temperature is uniform.

The steam box is characterized in that at least one partition plate is arranged in the inner box body, the inner box body is divided into at least two steam chambers which are distributed in parallel, steam inlets are respectively arranged on the side wall of each steam chamber, and each steam inlet is connected with one steam branch pipe. According to the process requirement and the actual size of each steam chamber, each steam chamber can be provided with one steam inlet or a plurality of steam inlets, each steam inlet is correspondingly connected with one steam branch pipe, and the total injection amount of the steam can be controlled by adjusting the flow and the number of the steam branch pipes. Generally, in order to improve the uniformity of steam entering the steam chamber, steam inlets are symmetrically arranged on two opposite side walls of each steam chamber, that is, the steam branch pipes are symmetrically arranged on two opposite side walls of the steam chamber in pairs, but the steam branch pipes on two sides can adopt pipes with the same diameter or different diameters.

The spraying direction of the steam spraying pipe is vertical to the steam input direction of the steam branch pipe entering the inner box body. I.e. the steam chamber, the direction of the incoming steam is perpendicular to the direction of the steam jet, thus on the one hand avoiding the negative effects of steam impinging on the sheets and on the other hand preventing condensed water possibly carried by the steam from being sprayed onto the sheets.

Or the steam input direction of the steam branch pipe entering the inner box body is parallel to the paper running direction, an included angle of 75-85 degrees is formed between the spraying direction of the steam spraying pipe and the paper running direction, and the spraying direction of the steam spraying pipe is opposite to the paper running direction. This structure makes and advances along the opposite direction of the traffic direction with the paper from steam injection pipe spun steam, can bring the cold air in the surrounding environment into when the paper operation gets into the steam chest, the speed of a motor vehicle of paper machine is faster, the more the cold air that the paper was brought into, the cold air enters into and can reduce the temperature of steam between steam chest and the paper, thereby probably form the comdenstion water in the bottom of steam chest, the steam that the reverse blowing comes is favorable to preventing the entering of cold air, effectively prevent the formation of steam chest bottom comdenstion water.

The inner hole of the steam injection pipe is a conical hole, and the diameter of the inner hole at the inlet end of the steam injection pipe is larger than that of the inner hole at the outlet end of the steam injection pipe. In the steam injection process, because the diameter of the inner hole of the steam injection pipe is gradually reduced, the steam speed is continuously improved after the steam enters the steam injection pipe, so that the steam is more favorably prevented from condensing and forming condensed water on the inner hole wall of the steam injection pipe, and the condensed water which is possibly formed can be broken. The steam jet pipe is a round pipe, and the outer wall of the steam jet pipe is gradually thinned to zero from bottom to top at the position close to the inlet end, so that water which is possibly condensed on the jet pipe can flow downwards along the inclined wall and cannot flow into the steam channel of the jet pipe. Each steam injection pipe is vertical or the slope is installed between first bottom plate and second bottom plate, and the steam injection pipe passes first bottom plate after-fixing on the second bottom plate, and its entry end top surface exceeds first bottom plate by 10 ~ 20mm, can effectively avoid in the comdenstion water that forms gets into the steam injection pipe in the steam chamber.

Preferably, the taper angle of the tapered hole is 0.5 to 2 °.

A steam return pipe is externally connected to the joint of the steam circulation pipe and the steam inlet pipe; the steam reflux pipe is provided with a reflux valve, the steam main pipe is provided with a main pipe control valve, the steam inlet main pipe is provided with an air inlet valve, and the steam branch pipe is provided with a branch pipe control valve. The steam circulating pipe is a three-way pipe, one end of the steam circulating pipe is connected with the preheating outlet, the other end of the steam circulating pipe is connected with the steam inlet main pipe, the other end of the steam circulating pipe is connected with the steam return pipe, and the end part connected with the steam return pipe and the steam inlet main pipe is provided with a return valve and a steam inlet valve for controlling the steam flow of each pipe. According to actual needs, the bottom of the steam circulating pipe can be further provided with a condensate pipe and a drain valve for discharging condensate which enters the steam circulating pipe from the preheating chamber and the bottom of the box body in a preheating mode. In addition, a condensate pipe and a drain valve can be arranged at the tail end of the steam inlet main pipe and used for discharging condensate water in the steam inlet main pipe. The steam discharged from the steam return pipe can be sent into an external heater and heated for recycling.

The method for adjusting the moisture of the paper by the steam box adopting the circulating steam comprises the following steps: steam from the steam main pipe firstly enters the box body preheating chamber from the preheating inlet, and preheats the inner box body and the steam injection pipe along the channel trend of the box body preheating chamber; after preheating is completed, steam discharged from the preheating outlet is sent into the steam inlet main pipe through the steam circulating pipe, then is distributed to the steam branch pipes through the steam inlet main pipe, enters the inner box body through the steam branch pipes, and finally is sprayed to the surface of paper through the steam spraying pipes. In the process, steam in the steam main pipe is continuously input, and the steam is sprayed after passing through the box preheating chamber, so that the temperature outside the inner box can be kept slightly higher than the temperature inside the inner box, and the formation of condensed water drops can be effectively prevented. Meanwhile, the steam in the preheating chamber of the box body keeps flowing in a single direction, and the preheating uniformity of the inner box body and the steam injection pipe is ensured. In addition, in the process, when the inner box and the steam injection pipe in the steam box are preheated for the first time (namely, the first preheating when the equipment is just started), the steam which comes out from the preheating chamber of the box body after preheating can not meet the injection requirement due to the temperature, so that the steam can not be recycled and needs to be discharged, and the steam can be discharged from a steam return pipe generally.

The steam branch pipes are uniformly distributed along the transverse direction of the paper machine and correspond to the steam chambers of the steam box, each steam chamber is communicated with one or more steam branch pipes, and the steam branch pipes are provided with control valves, so that the steam flow of the corresponding steam chambers can be controlled by controlling the opening degree of the steam branch pipes, and the purpose of adjusting the moisture content of paper sheets is achieved.

Compared with the prior art, the utility model, following beneficial effect has:

firstly, steam is advanced to preheat inner box body and steam emission pipe in the box body preheating chamber, sprays in the box body in reentrant, on the one hand make full use of the steam heat, reduces energy loss, and on the other hand can make the temperature of inner box body be not less than the steam temperature who spouts the paper surface all the time, effectively reduces the production of comdenstion water.

In second, this steam chest, the hole of steam injection pipe is the bell mouth, and its entry end is big, and the exit end is little, and steam velocity can constantly improve behind the steam admission steam injection pipe, more is favorable to preventing like this that steam from condensing and forming the comdenstion water on the inner hole wall of steam injection pipe, still can break the comdenstion water that probably has formed simultaneously.

And thirdly, the inlet end of the steam injection pipe is conical, so that the condensed water formed on the outer wall of the steam injection pipe can be effectively prevented from flowing into the steam injection pipe, can directly enter the bottom plate of the steam box along the outer wall, and is discharged through an external drain pipe.

Fourth, in this steam chest, heat the steam injection pipe through the steam that comes from the steam house steward, send into the steam injection pipe with the steam circulation that has already preheated again and spray, can guarantee that the temperature outside the steam injection pipe is higher than the intraductal temperature of steam injection all the time slightly, avoided steam to take place the condensation phenomenon in the steam injection pipe to avoid producing the phenomenon that the condensate water drips to the paper surface.

Fifthly, in the steam box, the spraying direction of the steam spraying pipe is obliquely arranged and is opposite to the running direction of the paper, so that the cold air in the surrounding environment can be effectively prevented from being brought into the space between the steam box and the paper by the paper.

Drawings

Fig. 1 is a schematic structural view of the steam box.

Fig. 2 is a sectional view a-a of fig. 1 when the steam injection pipes are vertically arranged in embodiment 1.

Fig. 3 is a schematic structural view of a steam injection pipe.

Fig. 4 is a view in the direction B of fig. 3.

Fig. 5 is a schematic structural diagram of the first base plate.

Fig. 6 is a schematic structural diagram of the second base plate.

Fig. 7 is a partial cross-sectional view C-C of fig. 6.

FIG. 8 is a sectional view taken along line A-A of FIG. 1 in the case where the steam injection pipes are arranged obliquely in example 5.

FIG. 9 is a cross-sectional view of the large and small holes of the second base plate in example 5.

In the above figures, the reference numerals are as follows: 1 is a steam main pipe, 2 is a main pipe control valve, 3 is a steam circulation pipe, 4 is a return valve, 5 is a steam return pipe, 6 is an air inlet valve, 7 is a steam inlet main pipe, 8 is a first steam branch pipe, 9 is a second steam branch pipe, 10 is a branch pipe control valve, 11 is a first condensate pipe, 12 is an upper preheating chamber, 13 is a bottom preheating chamber, 14 is a steam injection pipe, 14-1 is an inner hole, 15 is a first bottom plate, 15-1 is a long hole, 15-2 is a round hole, 16 is a second bottom plate, 16-1 is a large hole, 16-2 is a small hole, 17 is a partition plate, 18 is a second condensate pipe, 19 is a third condensate pipe, 20 is an inner box body, 21 is an outer box body, and 22 is paper.

Detailed Description

The present invention will be described in further detail with reference to examples, but the present invention is not limited thereto.

Example 1

In this embodiment, a steam box using circulating steam, as shown in fig. 1 or fig. 2, mainly includes a steam main pipe 1, a steam circulating pipe 3, a steam return pipe 5, a steam inlet main pipe 7, steam branch pipes (including a first steam branch pipe 8 and a second steam branch pipe 9) and a steam box body (mainly composed of an inner box body 20, an outer box body 21, a first soleplate 15 and a second soleplate 16), a uniflow-type box body preheating chamber (composed of an upper preheating chamber 12 and a bottom preheating chamber 13) with one side communicated is formed between the outer box body and the inner box body, a preheating inlet of the box body preheating chamber is connected with the steam main pipe, a preheating outlet of the box body preheating chamber is connected with the steam circulating pipe, the steam circulating pipe is communicated with the steam inlet main pipe, and the steam inlet main pipe is connected with the inside of the inner box; the bottom of the inner box body is distributed with steam injection pipes. The inner box body is surrounded by the outer box body, and the space in the inner box body is preheated and insulated through a box body preheating chamber formed between the inner box body and the outer box body; the box body preheating chamber is designed to be a one-way flow type structure with only one side communicated, so that steam in the box body preheating chamber gradually flows along the flow channel, and uniform preheating is ensured. The steam from the steam main pipe is used for preheating and then used for spraying, on one hand, the heat of the steam can be fully utilized, energy loss is reduced, on the other hand, the temperature outside the inner box body is slightly higher than the temperature in the inner box body along with the continuous input of the steam, and the formation of condensed water drops can be effectively prevented.

The steam box comprises the following structures:

in the steam box body, the inner cavity of the inner box body is transversely and uniformly divided into a plurality of steam chambers by partition boards 17, so that the transverse moisture content of paper can be adjusted, the left, right, front, back and upper parts of the inner box body are provided with upper preheating chambers 12, and the lower part of the inner box body is provided with a bottom preheating chamber 13 consisting of a first bottom plate 15 and a second bottom plate 16. The upper preheating chamber and the bottom preheating chamber are communicated with each other only at one side to form a box body preheating chamber with unidirectional flow. In the steam chamber, a third condensate pipe 19 and a drain valve are arranged above the first bottom plate for discharging condensate possibly formed in the steam chamber in time.

The steam main pipe 1 is connected with a preheating inlet on the side wall of the upper preheating chamber, and a main pipe control valve 2 is arranged at the preheating inlet and used for adjusting and controlling the steam flow in the steam main pipe.

The steam main pipe and the steam circulating pipe are arranged on the same side of the outer box body, and the channel for steam to enter the bottom preheating chamber from the upper preheating chamber is arranged on the other side, so that the full utilization of the steam is ensured, all parts of the box body of the steam box are fully heated, and the steam box has uniform temperature.

The steam circulating pipe 3 is a three-way pipe, one end of the steam circulating pipe is connected with a preheating outlet of the preheating chamber at the bottom, the other end of the steam circulating pipe is connected with the steam backflow pipe 5, the other end of the steam circulating pipe is connected with the steam inlet main pipe 7, and the end parts connected with the steam backflow pipe and the steam inlet main pipe are respectively provided with a backflow valve 4 and a steam inlet valve 6 for controlling the steam flow of the corresponding pipeline. The bottom of the steam circulation pipe is provided with a second condensate pipe 18 and a drain valve for discharging condensed water which may be generated in the steam circulation pipe preheated from the upper preheating chamber and the bottom, and the end of the steam inlet main pipe is provided with a first condensate pipe 11 and a drain valve for discharging condensed water which may be generated in the steam inlet main pipe. The steam discharged from the steam return pipe can be sent into the external heater again, and can be recycled after being heated.

First steam branch pipe 8 and second steam branch pipe 9 install respectively on steam main both sides between admission valve 6 and the first condensate pipe, along the horizontal evenly distributed of paper machine, as shown in fig. 2, the bilateral symmetry that every steam chamber is relative sets up a first steam branch pipe and a second steam branch pipe, the pipe diameter of first steam branch pipe is greater than the pipe diameter of second steam branch pipe, install branch pipe control valve 10 on the first steam branch pipe, the steam flow of control corresponding branch pipe, and there is not the valve on the second steam branch pipe, be in normally open state, do not control steam flow. The purpose of adjusting the injection amount can be achieved by adjusting the steam flow in the first steam branch pipe, so that the structural design can effectively reduce the number and size of the valves and reduce the equipment cost.

The steam injection pipes 14 are fixed to the second soleplate 16 after passing through the first soleplate 15 and the bottom preheating chamber. The steam inlet of the steam jet pipe is higher than the first bottom plate by about 10mm, so that condensed water formed in the steam box can be prevented from entering the steam jet pipe.

As shown in fig. 3 or 4, the steam injection pipe is shaped like a circular pipe, and the side wall of the steam injection pipe is gradually thinned to zero at a position close to the steam inlet, so that condensed water possibly generated on the steam injection pipe can flow downwards along the inclined wall and cannot flow into the steam channel (i.e. the inner hole) of the steam injection pipe. Meanwhile, the inner hole 14-1 of the steam injection pipe is a tapered hole, the inlet end of the inner hole is large, the outlet end of the inner hole is small, and the taper angle is about 1 degree. After the steam enters the steam injection pipe, the flow area is gradually reduced, so that the steam speed is continuously improved, the steam is more favorably prevented from condensing on the inner hole wall of the steam injection pipe and forming condensed water, and the condensed water which is possibly formed can be broken.

As shown in FIG. 5, the first base plate 15 is formed with a plurality of circular holes 15-2 each having a diameter corresponding to the outer diameter of the steam injection pipe for fixing the steam injection pipe, and has a long hole 15-1 formed at one side thereof for communicating the upper preheating chamber with the lower preheating chamber, and in the case preheating chamber, the long hole is formed at the opposite side of the preheating inlet of the case, through which steam is introduced from the upper preheating chamber into the lower preheating chamber, and through which condensed water in the upper preheating chamber is introduced into the lower preheating chamber and is finally discharged through a second condensed water pipe or a steam return pipe connected to a steam circulation pipe.

As shown in fig. 6 or 7, the second bottom plate 16 is provided with a pair of large holes 16-1 and small holes 16-2 (as shown in fig. 7, the large holes and the small holes form a stepped hole) at positions corresponding to the first bottom plate, the diameter of the large holes is matched with the outer diameter of the steam injection pipe, the diameter of the small holes is matched with the inner diameter of the outlet end of the steam injection pipe, the large holes and the small holes have the same central line, and the steam entering the steam injection pipe is injected onto the surface of the paper 22 through the small holes.

The method for adjusting the moisture of the paper by the steam box adopting the circulating steam comprises the following steps:

firstly, the steam inlet valve 6 is closed, the main pipe control valve 2 and the return valve 4 are opened, the whole steam box body is preheated, and the steam is prevented from generating condensed water when entering the steam box. When the temperature of the steam box body reaches the temperature of steam, preheating is completed, and the steam box starts to work normally; at the moment, the reflux valve 4 is closed, the steam inlet valve 6 is opened at the same time, steam from the steam main pipe enters the steam inlet main pipe after sequentially passing through the upper preheating chamber and the bottom preheating chamber, then the steam enters each steam chamber of the inner box body through the first steam branch pipe and the second steam branch pipe, and finally the steam is sprayed onto the surface of the paper through the steam spraying pipe.

In the process, firstly, the steam in the first steam branch pipe and the second steam branch pipe enters the steam chamber from the side, namely the direction of the steam is perpendicular to the direction of the steam sprayed to the paper, so that the adverse effect caused by the fact that the steam directly impacts the paper is avoided on one hand, and on the other hand, the condensate water possibly carried in the steam is prevented from being directly sprayed to the paper.

Secondly, steam passes through the steam jet stack and spouts the paper surface after getting into the steam chamber again, because steam that the steam house steward came passes through the box preheating chamber earlier before getting into the steam chamber, internal box and steam jet stack have all been preheated, the temperature of whole steam box can not be less than the steam temperature who gets into in the steam chamber promptly, therefore, steam can not produce the comdenstion water when getting into the steam jet stack, and simultaneously, the steam inlet of steam jet stack outer wall is the toper, even so produce the comdenstion water on the outer wall of steam jet stack, these comdenstion waters also can not flow in the steam jet stack, and can follow on its outer wall directly gets into first bottom plate, then discharge through its external third condensate pipe. In addition, the steam inlet of the steam jet pipe is higher than the first bottom plate by about 10mm, so that condensed water formed in the steam chamber can be effectively prevented from entering the steam jet pipe.

Thirdly, the inner hole of the steam injection pipe is a tapered hole, the inlet end of the steam injection pipe is large, the outlet end of the steam injection pipe is small, and the taper angle is about 1 degree. Therefore, after the steam enters the steam injection pipe, the steam speed is continuously improved, so that the steam is more favorably prevented from condensing on the inner hole wall of the steam injection pipe and forming condensed water, and the condensed water which is possibly formed can be broken.

In practical application, because before entering the steam chamber, steam has passed through the box preheating chamber, can produce certain heat loss, consequently for the temperature that guarantees to get into in the steam chamber satisfies the technology demand, the temperature that gets into the steam house steward is generally 1 ~ 2 ℃ higher than the injection temperature that the steam chamber required.

First steam branch pipe and second steam branch pipe are along the horizontal evenly distributed of paper machine, and every steam chamber communicates with each other with a first steam branch pipe and a second steam branch pipe, installs the branch pipe control valve on the first steam branch pipe, does not have the valve on the second steam branch pipe, because the pipe diameter of first steam branch pipe is greater than the pipe diameter of second steam branch pipe to can come the steam flow of control corresponding steam chamber through the steam flow in the first steam branch pipe of independent control, reach the purpose of adjusting paper banner moisture content.

Example 2

Compared with the steam box in the embodiment 1, the steam box adopting the circulating steam has the difference that three sides of the first bottom plate extend outwards to be connected with the outer box body to form a partition structure, and the fourth side does not extend outwards and is cut at the joint of the fourth side and the bottom of the inner box body, so that the upper preheating chamber is directly communicated with the bottom preheating chamber.

Example 3

Compared with the steam box in embodiment 1, the steam box using circulating steam in this embodiment is different in that four sides of the first bottom plate extend outward to be connected with the outer box body, but three sides of the first bottom plate are sealed to form a partition structure, and a plurality of through holes are formed in the fourth side of the first bottom plate, so that the upper preheating chamber and the bottom preheating chamber are communicated through the through holes.

Example 4

Compared with the steam box in the embodiment 1, the steam box in the embodiment adopting the circulating steam has the difference that only one side of each steam box is provided with a steam branch pipe, and each steam branch pipe is correspondingly provided with a branch pipe control valve.

Example 5

Compared with the steam box in the embodiment 1, the steam box in the embodiment adopts the circulating steam, and as shown in fig. 8, the steam input direction of the steam branch pipe entering the inner box body is parallel to the paper running direction, an included angle a of 75-85 degrees is formed between the spraying direction of the steam spraying pipe and the paper running direction (in the embodiment, the included angle a is 85 degrees), and the spraying direction of the steam spraying pipe is opposite to the paper running direction. This structure makes and advances along the opposite direction of the traffic direction with the paper from steam injection pipe spun steam, can bring the cold air in the surrounding environment into when the paper operation gets into the steam chest, the speed of a motor vehicle of paper machine is faster, the more the cold air that the paper was brought into, the cold air enters into and can reduce the temperature of steam between steam chest and the paper, thereby probably form the comdenstion water in the bottom of steam chest, the steam that the reverse blowing comes is favorable to preventing the entering of cold air, effectively prevent the formation of steam chest bottom comdenstion water.

Correspondingly, a plurality of elliptical holes are formed in the first bottom plate, so that the elliptical holes are matched with the outer diameter of the steam jet pipe and used for fixing the steam jet pipe. As shown in fig. 9, the second bottom plate is provided with a large hole and a small hole in pairs at positions corresponding to the first bottom plate, the large hole and the small hole are elliptical holes, the large hole and the small hole form an inclined stepped hole, the inclination angle b of the inclined stepped hole is 85 degrees, the size of the large hole is matched with the outer diameter of the steam injection pipe, the size of the small hole is matched with the inner diameter of the outlet end of the steam injection pipe, and steam entering the steam injection pipe is injected onto the surface of paper through the small hole.

As described above, the present invention can be realized well, and the above embodiments are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention; all equivalent changes and modifications made according to the present invention are intended to be covered by the scope of the claims of the present invention.

Claims (9)

1. A steam box adopting circulating steam is characterized by comprising an outer box body, an inner box body, a steam main pipe, a steam circulating pipe, a steam inlet main pipe and a steam branch pipe, wherein a one-way flow type box body preheating chamber communicated with one side is formed between the outer box body and the inner box body; the bottom of the inner box body is distributed with steam injection pipes.

2. The steam box using the circulating steam as claimed in claim 1, wherein the cross section of the box preheating chamber in the steam flowing direction is in a rectangular ring shape, and of two opposite sides of the rectangular ring, one side of the rectangular ring is separated from the middle part of the rectangular ring, and the other side of the rectangular ring is communicated with the middle part of the rectangular ring; in one side of the middle partition, a preheating inlet and a preheating outlet are respectively arranged on two sides of the partition.

3. The steam box of claim 2, wherein the box preheating chamber is vertically disposed on one side of the middle partition, the preheating inlet is disposed above the partition, and the preheating outlet is disposed below the partition.

4. The steam box of claim 3, wherein the inner box has a first bottom plate at the bottom thereof, and the outer box has a second bottom plate at the bottom thereof, the second bottom plate being located below the first bottom plate;

on one side of the partition in the middle of the box preheating chamber, a first bottom plate extends outwards from the inner box to the outer box, and a partition structure is formed at the extending part of the first bottom plate; and a preheating outlet is formed between the first bottom plate and the second bottom plate and is positioned below the partition structure.

5. The steam box of claim 1, wherein the inner box is provided with at least one partition plate to divide the inner box into at least two steam chambers arranged in parallel, each steam chamber is provided with steam inlets on a side wall thereof, and each steam inlet is connected to one steam branch pipe.

6. The steam box using the circulating steam as claimed in claim 1, wherein the injection direction of the steam injection pipe is perpendicular to the steam input direction of the steam branch pipe entering the inner box body;

or the steam input direction of the steam branch pipe entering the inner box body is parallel to the paper running direction, an included angle of 75-85 degrees is formed between the spraying direction of the steam spraying pipe and the paper running direction, and the spraying direction of the steam spraying pipe is opposite to the paper running direction.

7. The steam box of claim 1, wherein the steam injection pipe has a tapered inner bore, and the diameter of the inner bore at the inlet end of the steam injection pipe is larger than the diameter of the inner bore at the outlet end of the steam injection pipe.

8. A steam box using circulating steam as claimed in claim 7, wherein the taper angle of the tapered hole is 0.5 ° to 2 °.

9. The steam box of claim 1, wherein the junction of the steam circulation pipe and the steam inlet pipe is further externally connected with a steam return pipe;

the steam reflux pipe is provided with a reflux valve, the steam main pipe is provided with a main pipe control valve, the steam inlet main pipe is provided with an air inlet valve, and the steam branch pipe is provided with a branch pipe control valve.

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