EP4675215A1

EP4675215A1 - A nozzle for an apparatus for cleaning boiler surfaces

Info

Publication number: EP4675215A1
Application number: EP24185976.8A
Authority: EP
Inventors: Kristian Hansen
Original assignee: Dublix Technology ApS
Current assignee: Dublix Technology ApS
Priority date: 2024-07-02
Filing date: 2024-07-02
Publication date: 2026-01-07

Abstract

The present invention concerns a nozzle for a rotating nozzle head in an apparatus for cleaning open draft boiler surfaces in a combustion or incineration plant by dispensing a liquid with low pressure, said nozzle having an axial liquid flow direction and comprises a nozzle body having a first body portion and a second body portion, wherein a plurality of guiding holes are provided in the first body portion which are adapted to guiding liquid towards a nozzle opening, wherein said guiding holes are provided with an inclination relative to the axial direction and converging into a central axial outlet tube through the second body portion to the nozzle opening where the liquid is dispensed.

Description

FIELD OF THE INVENTION

The present invention relates to a nozzle for an apparatus for cleaning open draft boiler surfaces in a combustion or incineration plant. The invention also relates to an apparatus with at least one such nozzle.

BACKGROUND OF THE INVENTION

Such apparatus comprises a cleaning head having a coupling for connecting a cleaning liquid hose to the cleaning head for feeding a cleaning liquid to a rotating nozzle head having a plurality of nozzles from which the cleaning liquid can be sprayed against boiler surfaces during rotation of the nozzle head.
An apparatus for cleaning open draft boiler surfaces in a combustion or incineration plant in service is known from WO2021/063465A1 and EP-A-1291598 . A cleaning head is provided on the end and connected to a flexible hose, i.e. the liquid cleaning hose, and can simply be lowered through an opening provided in the top of the open draft of the boiler to be cleaned. The cleaning head is moved downwards while cleaning liquid is supplied to the nozzles and thereby sprayed onto the surfaces to be cleaned inside the boiler. Since the apparatus is positioned inside the open draft only during cleaning operations, the apparatus can be relatively simple as the cleaning fluid will keep the apparatus cool during the cleaning operation and the apparatus will not have to suffer the high temperatures inside the open draft of the combustion or incineration plant in service. Furthermore, the flexible hose construction reduces the amount of space required for introducing the cleaning apparatus into the open draft, thereby enabling the use of the apparatus in connection with existing plants substantially without any modifications thereof.
In order to achieve a good cleaning of the inner surfaces, the cleaning heads are produced as with either clockwise (CW) rotation or counter-clockwise (CCW) rotation. for many years it is found useful that the cleaning operation comprises both a cleaning with a CW cleaning head and afterwards a CCW cleaning head or vice versa, so that the inside of the boiler may be exposed to changing angles of the cleaning spray.
The boiler may be up to 900-1000°C inside during operation and thus also when the cleaning operation is carried out. Therefore it is realised that in order to achieve an effective cleaning, the nozzles should ensure that the water is sprayed so that the water spray does not spread out too early and thereby simply evaporates inside the boiler before reaching the boiler surfaces to be cleaned.
Accordingly, it is an object of the present invention to provide a nozzle for the boiler cleaning apparatus of the aforementioned kind, which can ensure an effective cleaning. Additionally, it may also be an objective to provide a nozzle that can reduce the consumption of water during the cleaning operation.

SUMMARY OF THE INVENTION

This object is achieved in a first aspect of the invention by providing a nozzle for a nozzle head in an apparatus for cleaning open draft boiler surfaces in a combustion or incineration plant by dispensing a liquid with low pressure, said nozzle having an axial liquid flow direction and comprises a nozzle body having a first body portion and a second body portion, wherein
a plurality of guiding holes are provided in the first body portion which are adapted to guiding liquid towards a nozzle opening, wherein said guiding holes are provided with an inclination relative to the axial direction and converging into a central axial outlet tube through the second body portion to the nozzle opening where the liquid is dispensed.
The nozzle according to the invention comprises multiple guiding tubes which are utilized to guide the liquid to the nozzle opening where the liquid is dispensed. The way of the multiple tubes is led to the nozzle outlet that results in stabilizing the jet of the liquid. As a result, the jet of the liquid is focused to reach farther, such as approx. 50 cm or longer.
Accordingly, the invention discloses a nozzle which is mounted on a nozzle head for the application of boiler cleaning. For this purpose, the nozzle dispenses a liquid, such as water, with low pressure in a focused jet in a laminar flow. Due to the low pressure of 1-3 bar and the focused jet of liquid the nozzle enables a long reaching jet of liquid whilst keeping the liquid consumption low.
By the nozzle a more homogeneous water beam is achieved when the water is leaving the nozzle and transported towards the boiler surface. The guiding tubes reduce the tendence of the water to be converted into smaller droplets and thereby reduce the evaporation of the water during the transport as it is experienced with previous nozzle designs. Besides a superior nozzle function, the nozzle according to the invention is also less expensive to produce due to the relatively simple design.
The nozzles in the nozzle head are suitable for an apparatus for cleaning open draft boiler surfaces in a combustion or incineration plant while the plant is in full operation e.g. incineration the fuel with hot boiler surfaces, e.g. as much as 900°-1000°C.
Preferably, said plurality of guiding holes are annularly equally spaced apart around the central axial axis of the nozzle. This ensures a homogeneous liquid flow through the nozzle.
In some preferred embodiments, the inclined guiding holes are inclined with an angle of 5-25°, preferably 8°-20°, more preferably approx. 11°. Hereby, the liquid enters the nozzle through the entry openings of each of the guiding holes on the first side of the nozzle and all of these liquid flows are then joined in the central outlet hole and dispensed through the outlet opening. In a currently preferred embodiment, a total of five guiding holes are provided.
In order to mount the nozzle to the nozzle head, the nozzle is provided with an external threading on the outside of the first body portion for threaded mounting of the nozzle in the nozzle head.
In a preferred embodiment, the nozzle is made monolithic. The nozzle according to the invention may accordingly be produced in one piece, such as machined from a block of steel, in particular the nozzle may be made of stainless steel.
In a second aspect of the invention, there is provided an apparatus comprising a cleaning head having a coupling for connecting a cleaning liquid hose to the cleaning head for feeding a cleaning liquid to a rotating nozzle head having a plurality of nozzles from which the cleaning liquid can be sprayed against boiler surfaces during rotation of the nozzle head, wherein at least one of said nozzles is a nozzle according to the above described first aspect. Thus it is realised that the nozzle according to the first aspect of the invention may be retrofitted to existing cleaning heads for boiler cleaning as well as provided on new cleaning apparatuses.

DETAILED DESCRIPTION

In the following, the invention is described in more detail with reference to the embodiments shown in the accompanying drawings, in which:

Fig. 1 is a schematic side view of a cleaning head according to the invention;
Fig. 2 is a side view of a nozzle according to an embodiment of the invention;
Fig. 3 is a cross-sectional view of cut A-A of fig. 2; and
Fig. 4 is an end view of said nozzle.

With reference to figure 1, a cleaning head 1 for cleaning open draft boiler surfaces in a combustion or incineration plant is shown. The cleaning head 1 comprises a main body 2 with a coupling in the form of a threated portion for connecting a cleaning liquid hose 8 to the cleaning head 1 for feeding a cleaning liquid 9 to a rotating nozzle head 4. The rotating nozzle head 4 comprises a plurality of nozzles 5. The nozzles 5 are provided such that when liquid is dispensed from the nozzles 5, is liquid spray causes the nozzle head 4 to rotate. The cleaning liquid 9 is sprayed through said nozzles 5 against boiler surfaces (not shown) during rotation of the nozzle head 4, when the cleaning head 1 is lowered down into the boiler 10. During the cleaning operation, the cleaning head may be lifted or lowered the cleaning head 1 as indicated by the arrow 14 (see fig. 1).
The nozzle 5 according to an embodiment of the invention is shown in figures 2-4. The nozzle 5 has an axial liquid flow direction and comprises a nozzle body 5' having a first body portion 51 and a second body portion 52. A plurality of guiding holes 54 are provided in the first body portion 51 which are adapted to guiding liquid towards a nozzle opening 56 at the end of the central outlet tube 55 in the second portion 52. The guiding holes 54 are provided with an inclination α relative to the axial direction CA and converging into the central axial outlet tube 55 through the second body portion 52 so that the liquid is forwarded to the nozzle opening 56 where the liquid is dispensed.
The guiding holes 54 are annularly equally spaced apart around the central axial axis CA of the nozzle 5. As shown in fig. 4, five guiding holes are provided in the shown embodiment, where the guiding holes 54 are inclined by 11°. However, by the invention it is realised that any other number of guiding holes and inclination angles may be provided. However, to ensure a laminar flow in the nozzle, the inclination angle should be an acute angle, preferably with an inclination of 25° or less.
As indicated in the figures, the nozzle 5 is made monolithic, i.e. in one piece, where the guiding holes 54 are drilled into a solid piece of metal from one side. The solid metal piece may be any suitable alloy, such as stainless steel. The central outlet tube hole 55 is also drilled into the nozzle body from the other side. All sharp edges are preferably without burrs so that the liquid flow is not disturbed.
In order to mount the nozzle 5 in the nozzle head 4 (see fig. 1) the first portion 51 of the nozzle body 5' is provided with an external threading 53 on the outside of the first body portion 51.
When the nozzle 5 is mounted on the nozzle head 4, pressurised liquid, for instance water at a pressure of 1-3 bars enters the five openings of the guiding holes 54 on the "inner" side of the nozzle 5. The liquid is then forwarded through the guiding holes and lead to the outlet tube 55 whereby the jet of the liquid dispensed through the outlet opening 56 is stabilised.
In general, when directional terms like "upper" and "lower" or similar directional references are used in the present disclosure, these terms are meant to be understood as relative terms e.g. where the term "upper" refers to a direction essentially opposite to the "lower", but it is realised that the planar assembly when in use can be positioned with any orientation.
Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms "comprising" or "comprises" do not exclude other possible elements or steps. Also, the mentioning of references such as "a" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.
Above, the invention is described with reference to some currently preferred embodiments. However, by the invention it is realised that other embodiments and variants may be provided without departing from the scope of the invention as defined in the accompanying claims.

Claims

A nozzle for a rotating nozzle head in an apparatus for cleaning open draft boiler surfaces in a combustion or incineration plant by dispensing a liquid with low pressure, said nozzle having an axial liquid flow direction and comprises a nozzle body having a first body portion and a second body portion, wherein
a plurality of guiding holes are provided in the first body portion which are adapted to guiding liquid towards a nozzle opening, wherein said guiding holes are provided with an inclination relative to the axial direction and converging into a central axial outlet tube through the second body portion to the nozzle opening where the liquid is dispensed.
A nozzle according to claim 1, wherein said plurality of guiding holes are annularly equally spaced apart around the central axial axis of the nozzle.
A nozzle according to claim 1 or 2, wherein the inclined guiding holes are inclined with an angle of 5°-25°, preferably 8°-20°, more preferably approx. 11°.
A nozzle according to any of the preceding claims, wherein a total of five guiding holes are provided.
A nozzle according to any of the preceding claims, wherein the nozzle is provided with an external threading on the outside of the first body portion for threaded mounting of the nozzle in the nozzle head.
A nozzle according to any of the preceding claims, wherein the nozzle is made monolithic.
A nozzle according to any of the preceding claims, wherein the nozzle is made of stainless steel.
An apparatus comprising a cleaning head having a coupling for connecting a cleaning liquid hose to the cleaning head for feeding a cleaning liquid to a rotating nozzle head having a plurality of nozzles from which the cleaning liquid can be sprayed against boiler surfaces during rotation of the nozzle head, wherein at least one of said nozzles is a nozzle according to any one of the preceding claims.