JP2010030739A - Incinerated ash carrying screw - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an incinerated ash carrying screw having improved heat resistance for achieving a longer life. <P>SOLUTION: The incinerated ash carrying screw comprises a cylindrical shaft member 13 including a cooling means, and a screw blade 14 spirally mounted on the outer periphery of the shaft member 13. The screw blade 14 is formed of a Ni base alloy and welded to the outer periphery of the shaft member 13 with a Ni base alloy. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a screw for incineration ash conveyance, and more particularly to a screw for conveying incineration ash such as paper sludge.

  Conventionally, papermaking sludge and the like generated in a paper mill are incinerated and discarded, and incinerator ash in a semi-molten state at a high temperature of 850 ° C. or higher is conveyed by a screw. This type of screw was installed in a stainless steel transport cylinder, and a stainless steel screw member was welded to the outer periphery of a stainless steel shaft member.

  However, in a corrosive environment at a high temperature of 850 ° C. or higher, it is necessary to consider heat resistance, and the shaft member can be temporarily solved by incorporating a water-cooling type cooling means. However, the water cooling effect does not work, the blade itself undergoes thermal deformation and cracks at an early stage, and cracks and wear also occur with the shaft member, which must be replaced after half a year of use. It is.

  Then, the objective of this invention is providing the screw for incineration ash conveyance which is excellent in heat resistance and can achieve long life.

In order to achieve the above object, an incineration ash conveyance screw according to one aspect of the present invention is
In a screw for incineration ash conveyance consisting of a cylindrical shaft member including a cooling means inside, and screw blades spirally attached to the outer periphery of the shaft member,
The screw blades are formed of a Ni-based alloy, and are welded to the outer periphery of the shaft member with a Ni-based alloy;
It is characterized by.

  Ni-based alloys are superior to stainless steel in terms of thermal conductivity, linear expansion coefficient, heat resistance, molten salt resistance, and the like. In the incineration ash conveying screw, the screw blades are made of Ni-based alloy and welded to the outer periphery of the shaft member with Ni-based alloy. No cracks occur and a longer life can be achieved than the conventional one.

  In the incineration ash conveying screw, an Ni-based alloy may be welded to the end of the shaft member. The heat resistance of the shaft member can be further improved.

  Hereinafter, the Example of the screw for incineration ash conveyance concerning this invention is described with reference to an accompanying drawing.

  FIG. 1 shows a main part of an incinerator for papermaking sludge, where 1 is a cyclone, 2 is a dust holder, and 3 is a cyclone ash cooler. The incinerated ash in a semi-molten state is charged into the cyclone 1 and transferred from the dust holder 2 to the cyclone ash cooler 3 and is conveyed in the cyclone ash cooler 3 in the direction of arrow A.

  The cyclone ash cooler 3 is composed of a conveying cylinder 11 and an incinerated ash conveying screw 12 (see FIG. 2) coaxially attached in the conveying cylinder 11. The incineration ash conveying screw 12 includes a cylindrical shaft member 13 including a water-cooling cooling means inside, and a screw blade 14 spirally attached to the outer peripheral portion of the shaft member 13. The length of the main body portion of the shaft member 13 is about 4800 mm and the diameter is about 400 mm. The outer diameter of the screw blade 14 is about 700 mm.

  The shaft member 13 is made of stainless steel (SUS316), is rotatably supported by the transport cylinder 11 by bearing portions 13a and 13b at both ends, and a driving force is transmitted from the bearing portion 13b side. Further, the cooling water supplied from the bearing portion 13a flows in the direction of the arrow A inside the shaft member 13, and is discharged from the bearing portion 13b.

  The screw blade 14 is formed of a Ni-based alloy (for example, Inconel 600 or Inconel 625, Inconel is a registered trademark of Inco Corporation), and is welded to the outer peripheral portion of the shaft member 13 with a Ni-based alloy. ing. The welding here is performed over the entire length of the joint between the screw blade 14 and the shaft member 13 by the PTA method (plasma powder welding).

  Further, the shaft member 13 is subjected to build-up welding with the same Ni-based alloy in the regions Y1 and Y2 shown in FIG. The build-up is one layer and the thickness is about 1.8 mm.

  Here, in Table 1 below, various types of conventionally used stainless steel (shown as material 1 in Table 1) and Ni-based alloys used in the present invention (shown as material 2 and material 3 in Table 1) are shown. Show performance.

  When the screw blades 14 are manufactured and installed in a facility (see FIG. 1) for continuously cooling the incinerated ash in a high temperature state in an incinerator for papermaking sludge and operated experimentally, even after half a year, the screw blades 14 There was no thermal deformation or cracking in itself. In addition, cracks and wear were not observed in the welded portion of the screw blade 14 to the shaft member 13. Furthermore, the wear in the build-up areas Y1 and Y2 of the shaft member 13 was not observed. It is estimated that the life of the incinerated ash conveying screw 12 is four times or longer.

(Other examples)
In addition, the screw for incineration ash conveyance concerning this invention is not limited to the said Example, It can change variously within the range of the summary.

  In particular, the build-up welding of the Ni-based alloy to the shaft member is not limited to the regions Y1 and Y2, and numerical values such as dimensions given in the examples are merely examples.

It is an elevational view showing the main part of an incinerator equipped with an embodiment of the screw for incineration ash conveyance according to the present invention. It is a front view which shows one Example of the screw for incineration ash conveyance which concerns on this invention.

Explanation of symbols

12 ... Screw for incineration ash conveyance 13 ... Shaft member 14 ... Screw blade

Claims (2)

In a screw for incineration ash conveyance consisting of a cylindrical shaft member including a cooling means inside, and screw blades spirally attached to the outer periphery of the shaft member,
The screw blades are formed of a Ni-based alloy, and are welded to the outer periphery of the shaft member with a Ni-based alloy;
A screw for incineration ash conveyance.   The incinerated ash conveying screw according to claim 1, wherein an Ni-based alloy is welded on the end of the shaft member.

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