02_NDPM21_SymFlo D Headbox_operator

Metso Learning

SymFlo D HeadboxGeneric Training Material

Sea Dragon Paper Industries (Taicang) Co., Ltd NDPM21

Metso Learning1

SymFlo D HeadboxNDPM21

SymFlo D

© Metso Paper, Inc. 2008

Metso Learning

SymFlo D Headbox Description

SymFlo is a hydraulic headbox specially designed to produce a stableslice jet and good CD profiles required on hybrid formers. The basic functions of the SymFlo headbox are uniform stock distribution across the entire width of the machine, deflocculation at two steps of tube banks from a larger to a smaller scale, and elimination of the effect of disturbances caused by the headbox surroundings with the help of an attenuator integrated into the headbox structure.

SymFlo is also designed for optimization of the basis weight profile byadjusting the stock consistency for each zone in the cross-machine direction.2

© Metso Paper, Inc. 2008

Metso Learning

SymFlo D Headbox- LayoutNDPM2110 9 5 4 15 14

1 2 3 4 5 6 7 8 9 10 11

11

7 12 8 6 3 3© Metso Paper, Inc. 2008

12 14 15 16 1

Inlet header Tube bank Equalizing chamber Attenuator Turbulence generator Slice channel Top slice Apron plate Top slice vertical adjustment mechanism Top slice horizontal adjustment mechanism Slice lip adjustment mechanism Slice lip Dilution equipment Dilution header Inlet header opening mechanism

2

16

Metso Learning

Main Dimensions and Production DataSymFlo D Headbox Cleanout and inspection doors can be found at the inlet header's back section, at the equalizing chamber, at the attenuator, and at the slice channel. The top and bottom frames are equipped with heating water connections. The inlet header is equipped with onesided feed, inlet from the back side. The dilution header is equipped with one-sided feed, inlet from the back side.

Flow Rate - min. 130 l/s/m - max. 220 l/s/m Design Speed - 1400 m/min Slice Outlet Width - 7080 mm Slice Opening Adjustment Range in Operation Position - 5… 40 mm

4

© Metso Paper, Inc. 2008

Metso Learning

Main Dimensions and Production DataSymFlo D Headbox Slice Opening Adjustment Range in Maintenance Position - 5… 70 mm Top Slice Horizontal Adjustment Range - 38 mm Slice Lip Stickout - 5 mm Number of Slice Lip Adjustors - 59 total Slice Lip Adjustor Spacing - 121.2 mm Maximum Permitted Difference in the Readings of Adjacent Adjustors - 0.3 mm

Number of Dilution Valves - 118 total Dilution Valve Spacing - 60 mm Design Inlet Header Recirculation as Percentage of Slice Flow - 10% Design Dilution Header Recirculation as Percentage of Dilution Flow - 15% Design Headbox Overflow as Percentage of Slice Flow - 3%

5

© Metso Paper, Inc. 2008

Metso Learning

SymFlo D Headbox - Construction

Metso Learning7

SymFlo D Headbox

42024© Metso Paper, Inc. 2008

Metso Learning

Headbox, Operation Stock flows into the headbox through an inlet header, which is a tube made of acid-proof stee

l and reinforced with support ribs. The inside surface of the tube is ground and electropolished. The inlet header equalizes stock pressure across the web. The flow of stock is diverted in the machine direction inside the inlet header. Stock flows into the inlet header from the back side. The front side end of the inlet header has a recirculation line equipped with recirculation valves. The design recirculation is 10% of the slice flow. The inlet header's geometry is optimized for the design flow, which contributes to a uniform pressure distribution across the machine.

Dilution water inlet

Inlet header

8

© Metso Paper, Inc. 2008

Metso Learning

SymFlo Headbox Inlet HeaderSight glass pipe

(From workshop, example only) 9© Metso Paper, Inc. 2008

Metso Learning

Headbox Flow Channels (Typical)

From the inlet header's front section stock flows into the equalizing chamber where the individual tube flows unite into one homogeneous flow. 10© Metso Paper, Inc. 2008

The inlet header's front section equalizes the pressure and jet velocity profiles in the headbox cross direction by means of pressure loss.

Metso Learning11

Headbox Flow Channels (Typical)

The attenuator is an open space above the equalizing chamber that connects to the equalizing chamber across the entire width of the headbox. The stock level inside the attenuator is kept at the desired level and the overflow volume is controlled by adjusting the air pressure inside the attenuator. The air inside the attenuator acts as the actual damper that reduces MD basis weight profile variations caused by pressure pulses in the short circulation.© Metso Paper, Inc. 2008

Metso Learning12

Headbox Flow Channels (Typical)

The turbulence generator combines two perforated plates and a tube bank. The lead-in ends of the tubes attach to the perforated plate. The tubes are circular at the start and gradually change to rectangular in order to maximize the open area of the turbulence generator's lead-out end. Powerful microturbulence is created in the turbulence generator tubes. This microturbulence breaks up fiber flocks and improves the quality of paper. The flow surface is also simultaneously maximized as the stock proceeds toward the slice channel.© Metso Paper, Inc. 2008

Metso Learning

SymFlo HeadboxElectropolishingMechanically grinded

Electropolished

All inside surfaces of the headbox, which are in contact with the stock are ground and electropolished.

13

© Metso Paper, Inc. 2008

Metso Learning

SymFlo HeadboxTurbulence Generator

The pipes are circular at the

inlet, transforming to rectangular in order t …… 此处隐藏：4055字，全部文档内容请下载后查看。喜欢就下载吧 ……