US20170261228A1

US20170261228A1 - Heating block for an electric continuous flow heater and electric continuous flow heater

Info

Publication number: US20170261228A1
Application number: US15/455,197
Authority: US
Inventors: Michael Grobe; Frank Uhr; Daniel Schäfer
Original assignee: Stiebel Eltron GmbH and Co KG
Current assignee: Stiebel Eltron GmbH and Co KG
Priority date: 2016-03-11
Filing date: 2017-03-10
Publication date: 2017-09-14
Also published as: DE102016002942A1

Abstract

The invention is directed to a heating block (100) for a continuous flow heater in which a water flow system with channels is arranged in the heating block (100). A heating path (300) of the water flow system forms a hottest channel (340) with a hottest heating element (341) during operation of the continuous flow heater. The hottest channel (340) is arranged downstream of at least one channel (310, 320, 330) of the heating path (300) in a flow direction (110). The hottest channel (340) of the heating path (300) is surrounded by at least four channels which are located between an outer surface (120) of the heating block (100) and the hottest channel (340). Accordingly, the hottest channel (340) of the continuous flow heater is surrounded by at least four channels and is shielded relative to an air space (160).

Description

RELATED APPLICATIONS

The present application claims priority to German Application No. 10 2016 002 942.0, filed on Mar. 11, 2016, the entirety of which is incorporated herein by reference.

BACKGROUND

Electric continuous flow heaters, in particular three-phase continuous flow heaters, having a heating block of plastic are known commercially. A water flow system comprising various channels which usually run parallel is arranged in the heating block. Advantageously, it is further known to use bare wire heating bodies which are arranged in a heating path in the water flow system. The final heating body arranged in a flow direction is the hottest as determined by function, since the water which has already been preheated by the other heating bodies is supplied to the final heating body viewed in flow direction and then heats the latter to the desired target temperature. This hottest heating body at the end of the heating path is the most prone to scaling.

SUMMARY

It is an object of the invention to prevent damage which can occur as a result of scaling of the hottest heating body and to provide a heating block which is better protected against damage due to scaling.
An object of the invention may be met through the features of claim 1 or through the features of claim 3.
The hottest heating body which is located at the end of the heating path viewed in flow direction is surrounded by other portions or channels of the water flow system, i.e., at least four other portions or channels of the water flow system are arranged around the hottest heating body. These at least four channels may be unheated sections of the water flow system or may also be heated sections of the water flow system.
In accordance with an embodiment of the invention, insulating trailing sections of the water flow system are arranged around the hottest heating body. These trailing sections are channels which are not heated and through which flows the water heated by the heating bodies. The unheated channels which serve as trailing sections and to electrically insulate the bare wire heating bodies located in the heating path are in the immediate vicinity of the hottest heating body and downstream of the latter viewed in flow direction.
Other heating channels are preferably arranged upstream of the hottest heating channel, and the hottest heating channel is connected downstream of these other heating channels viewed in flow direction of the water. Therefore, it is preferred that the hottest heating channel is surrounded by the rest of the heating channels or at least by a heating channel arranged upstream thereof and the channels of the trailing section.
The suggested heating block is preferably made of plastic, and the channels located therein as heating path, leading section or trailing section are arranged substantially in parallel in the heating body. The individual channels are connected to one another, respectively, in a foot piece and in a head piece so that the water flowing through the channels is diverted in the head and in the foot and is guided from one channel to the next channel.
The cold water flows through the heating body of the continuous flow heater initially through the channels which are arranged as leading sections in the heating body. Subsequently, the water from the channels of the leading section enter the channels of the heating path.
The channels, particularly the channels of the heating path, may preferably have a round cross section. According to an embodiment of the invention, the channels have at least partially an oval cross section diverging from the round cross section or have a cross section with two parallel sides joined by an arc. Accordingly, in a preferred embodiment, channels are suggested at least partially having a smaller width than height.
In the heating path, the water flows through the channels of the heating path either one after the other and/or preferably also at least partially in parallel. So-called parallel channels can be arranged thereafter or therebetween, and the parallel channels are preferably located between two channels of the heating path and accordingly connect two or three channels of the heating path.
The hottest heating channel in flow direction of the water to be heated preferably lies at the end of the heating path so that the water in the hottest heating channel is hottest and the bare wire coil of the hottest heating channel is accordingly also hottest. Scaling is most likely to occur at this hottest heating coil so that the water flow is reduced and the hottest heating channel could overheat. In case of damage, the hottest heating channel is surrounded by other channels according to the invention through which water preferably flows and/or no heating body is arranged so that the heating body remains tight overall even in case of damage in the hottest heating channel.
The hottest channel of the heating path is preferably surrounded by at least four channels which are located between an outer surface of the heating block and the hottest channel. Accordingly, the hottest channel during operation of the continuous flow heater is surrounded by at least four channels and is shielded from the air space.
According to an embodiment of the invention, the hottest channel is shielded from an outer surface by at least two unheated channels and at least two heated channels.
A preferred heating block for a continuous flow heater has at least two channels with one heating element in each instance. During operation of the continuous flow heater, the heating channel with the hottest heating element is hotter than the preceding heating element in flow direction. At least two unheated channels, as insulating leading section, are located upstream in flow direction of the channels with heating bodies. At least two channels are arranged as insulating trailing channels downstream of the heating channels in flow direction.
In a preferred embodiment, the hottest channel is surrounded by at least four channels so that the hottest channel is sealed relative to an air space by the surrounding channels and remains sealed off in case of a defect in the hottest channel.
According to a preferred embodiment, the heating path comprises three channels with a heating element in each instance and the hottest heating channel with a hottest heating element. The hottest heating channel is located downstream of the three heating channels in flow direction.
The hottest channel is preferably surrounded in the heating block by at least two channels and particularly by at least two, three or more than three unheated channels relative to an air space.
The channels are preferably arranged at least partially parallel to one another and parallel to the hottest channel.
The heating block is arranged in a housing of an electric continuous flow heater.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view a heating block with exposed cross-sections;

FIG. 2 shows a cross-sectional view of a heating block;

FIG. 3 shows a flow plan of the water flow system;

FIG. 4 shows electric connections of the heating body;

FIG. 5 shows a connection circuit board for the electric heating body;

FIG. 6 shows a star point bridge with connection of the heating body.

DETAILED DESCRIPTION

It will be appreciated by those ordinarily skilled in the art that the foregoing brief description and the following detailed description are exemplary (i.e., illustrative) and explanatory of the subject matter as set forth in the present disclosure, but are not intended to be restrictive thereof or limiting of the advantages that can be achieved by the present disclosure in various implementations.
It is noted that in this disclosure and particularly in the claims and/or paragraphs, terms such as “comprises”, “comprised”, “comprising” and the like can have the meaning attributed to it in U.S. Patent law; e.g., they can mean “includes”, “included”, “including”, and the like.
FIG. 1 shows a heating block 100 with an inlet 104 and an outlet 105 of an electric continuous flow heater. The heating block 100 is made of plastic and has a head 101. A water flow system is located in the heating block. Viewed in a flow direction 110, the water flow system comprises a leading section 200, followed by heating path 300 and a trailing section 500 following the heating path 300.
The leading section 200 and the trailing section 500 are provided for electric insulation relative to heating elements 311, 321, 331 and a hottest heating element 341 which are located in heating path 300. The leading section 200 is divided into a quantity of channels. Accordingly, the leading section 200 is divided into unheated and insulating channels 210, 220, 230, 240, 250.
Following the leading section 200 in flow direction 110 is the heating path 300, already mentioned, in which heating channels 310, 320, 330 and a hottest channel 340 are arranged in the embodiment example. A heating element 311, 321, 331 is arranged in a channel 310, 320, 330, respectively. The heating element 341 which is hottest during operation is arranged in the hottest channel 340. Therefore, during operation of the electric continuous flow heater 1, the hottest heating element 341 in the hottest channel 340 is the hottest because the hottest heating element further heats the water which has already been preheated by heating elements 311, 321, 331 so that the hottest heating element 341 is also the hottest in this case particularly at the end of the hottest channel 340 in flow direction 110.
Further, a flow unit 140 and an adjusting valve 130 are arranged at the heating block. The adjusting valve is preferably arranged in the leading section 200, where the flow unit 140 is also arranged.
The heating block 100 is shown in section in FIG. 2. The hottest heating body 341 which is arranged in the hottest channel 340 is surrounded by seven channels in the embodiment example. The seven channels seal off the hottest heating body 341 from an air space 160 and, accordingly, the hottest channel 340 is also shielded from, or at a distance from, an outer surface 120 of the heating block 100.
In the embodiment example, the hottest channel 340 is surrounded by three channels 310, 320, 330 which are heated. Further, the hottest channel 340 is surrounded by two parallel channels 410 and 420 in which the water coming from channel 320 and 330 is guided to the hottest channel 340 during operation of the continuous flow heater. The two parallel channels 410 and 420 serve to guide the already preheated water to the start of the hottest channel 340 during operation of the continuous flow heater 1. The deflection of the already preheated water takes place, seen in flow direction 110, downstream of the unheated parallel channels 410 and 420 in a foot 102 as is shown schematically in FIG. 3.
In the embodiment example shown in FIG. 4, the electrical connection of heating elements 311, 321 and 331 and of the hottest heating element 341 is carried out by a printed circuit board 600. In this embodiment, the printed circuit board 600 has a finger 601, 602, 603, 604 for connecting each heating element 311, 321 and 331 and the hottest element 341. These fingers 601, 602, 603, 604 are component parts of the printed circuit board 600, and conductor paths which are provided for the flow of electric current to heating elements 311, 321 and 331 and to the hottest element 341 are located on the fingers. In an embodiment, the printed circuit board 600 is arranged in head 101 in the area of the adjusting valve 130. The hottest channel 340 and the hottest heating element 341 are supplied with power via finger 604.
Heating elements 311, 321, 331 and the hottest heating element 341 are guided or stretch from head 101 to foot 102, and a star point bridge 103 by which the heating coils are electrically connected and accordingly arranged in a so-called electric star point as is shown in FIG. 6 is arranged in the area of the foot 102.
The trailing section 500 is divided into a plurality of channels 510, 520, 530 which are arranged in series one after the other.
Fingers 601, 602, 603, 604 of the heating body connection printed circuit board 600 are preferably configured to be resilient so that a tolerance compensation is achieved with respect to heating body connection pins of the heating bodies, preferably in head 101. The heating body connection pins can be located at different heights in the head 101 as a result of assembly tolerances and/or compressive stresses in the water. The printed circuit board 600 other serves to protect against wiring errors because only one assembling direction is possible and correct.
The printed circuit board 600, as “break-off circuit,” is preferably a component part of a main printed circuit board. The printed circuit board 600 is attached to the main printed circuit board, preferably at a predetermined breaking line.
The main circuit board is preferably manufactured together with the printed circuit board 600. This is preferably carried out in THT mounting and/or SMD mounting, and electronic components are connected by a solder wave to conductor paths of the printed circuit board 600 and main circuit board. During the production of the continuous flow heater, the printed circuit board 600 is broken off from the main circuit board and arranged at head 101.
While this invention has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications, and variations will be apparent to those ordinarily skilled in the art. Accordingly, the preferred embodiments of the invention as set forth above are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the inventions as defined in the following claims.

Claims

1. Heating block for a continuous flow heater comprising:

a water flow system,

wherein the water flow system is arranged in the heating block, and has a heating path, a channel of the heating path being the hottest during operation,

wherein a hottest heating element is arranged in the hottest channel, and the hottest channel is arranged downstream of at least one channel of the heating path in a flow direction,

wherein the hottest channel of the heating path is surrounded by at least four channels which are located between an outer surface of the heating block and the hottest channel so that the channel which is hottest during operation of the continuous flow heater is surrounded by at least four channels and is shielded relative to an air space.

2. Heating block according to claim 1, wherein the hottest channel is surrounded by at least two channels which are unheated, and the hottest channel is surrounded by at least two further channels of the heating path so that the hottest channel is shielded relative to an outer surface by at least two unheated channels and by at least two heated channels.

3. Heating block for a continuous flow heater comprising:

at least two channels having a heating element in each instance,

wherein the heating channel with the heating element is hotter than heating elements during operation of the continuous flow heater,

wherein at least two unheated channels as insulating leading section are located upstream of channels with heating bodies in a flow direction, and at least two channels as insulating trailing channels are arranged downstream of heating channels in the flow direction,

wherein the hottest channel is surrounded by at least four channels so that the hottest channel is sealed relative to, and sealed off from, an air space by the surrounding channels in case of a defect in the hottest channel.

4. Heating block according to claim 3,

wherein the heating path is formed of three channels with a heating element and the hottest heating channel, and

wherein the hottest channel is located downstream of the three channels viewed in flow direction.

5. Heating block according to claim 4.

wherein the hottest channel is surrounded in the heating block by at least two channels and particularly at least two, three or more than three unheated channels relative to an air space.

6. Heating block according to claim 5, wherein the channels are arranged at least partially parallel to one another and parallel to the hottest channel.

7. Electric continuous flow heater with a heating block according to claim 3.