GB2407365A

GB2407365A - Boiler condensate collector

Info

Publication number: GB2407365A
Application number: GB0324569A
Authority: GB
Inventors: Martin Hodgson
Original assignee: Worcester Heat Systems Ltd
Current assignee: Bosch Thermotechnology Ltd
Priority date: 2003-10-22
Filing date: 2003-10-22
Publication date: 2005-04-27
Anticipated expiration: 2023-10-22
Also published as: GB0324569D0; GB2407365B

Abstract

The collector 10 has a housing 12 that is receivable in a condensing boiler assembly. An inlet 14, outlet 16, and drain valve 18 are positioned in the housing with the drain valve including an opening mechanism 32. The opening mechanism includes a float arm 32, a float 36, an over-centre toggle mechanism 38, and an actuating mechanism 40. When the collector is empty (with the float positioned near the base 22) the toggle mechanism is biassed by a spring 54 to prevent the escape of any condensate in the housing. The opening mechanism is activated when the float reaches a predetermined position within the housing. The opening and closing of the drain valve is achieved with a 'snap' action of the mechanism 32.

Description

BOILER CONDENSATE COLLECTOR

This invention relates to a condensate collector for a condensing boiler assembly.

It is common practice to use a U-bend trap collector to collect condensate formed during operation of a condensing boiler assembly. The U- bend trap is used either alone or in combination with a siphon. When used alone' there is a possibility that, due to an obstruction of the normal flue gas flow path, the water seal of the U bend trap can be breached and therefore flue gas can be discharged to the condensate drain. This can be hazardous.

When the U-bend trap is used in conjunction with a siphon, which is typically an inverted U-bend pipe connected at one end to a chamber into which the U-bend trap discharges and connected at its other end to a drain, problems occur when condensate drips from the siphon into the drain. During cold weather, the drips tend to freeze easily, resulting in blockage of the drain and or siphon.

The present invention seeks to provide a solution to these problems.

According to a first aspect of the present invention, there is provided a boiler condensate collector comprising a housing, which is receivable in a boiler body of a condensing boiler assembly and which has an inlet for condensate from a heat exchanger of the condensing boiler assembly and an outlet for connection to a drain, and a drain valve which is positioned in or at the outlet of the housing and which opens to drain when condensate in the housing reaches a predetermined level.

Preferable and/or optional features of the first aspect of the invention are set forth in claims 2 to 9, inclusive.

According to a second aspect of the present invention, there is provided a condensing boiler assembly comprising a boiler condensate collector in accordance with the f rst aspect of the invention.

The present invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which; Figure 1 is a schematic partial sectional view through a housing of one embodiment of a boiler condensate collector, in accordance with the first aspect of the present invention and shown in a first condition; and Figure 2 is a view similar to Figure 1, but showing the boiler condensate collector in a second condition.

Referring to the drawings, there is shown a boiler condensate collector 10 which comprises a housing 12 having an inlet 14 and an outlet 16, and a drain valve 18 which is positioned in or at the outlet 16 of the housing 12.

The housing 12 is typically formed from moulded plastics material, generally in the shape of a box. The inlet 14 is formed in the upper or top surface 20 of the housing 12 and the outlet 16 is formed in the lower surface or base 22. The upper surface 20 of the housing 12 is openable to provide access to the interior, for example, for maintenance and servicing. A float recess 24, access to which is from within the housing 12, is formed in the upper surface 20.

The drain valve 18 includes a valve body 26 having a valve seat 28, a valve head 30 which is slidable in the valve body 26 towards and away from the valve seat 28, and an opening mechanism 32 disposed within the housing 12 and by which the valve head 30 is moved relative to the valve seat 28.

The opening mechanism 32 comprises a float arm 34, one end of which is pivotably mounted to an interior surface of the housing 12 at a position which is adjacent to the inlet 14, a float 36 disposed at the other end of the float arm 34, an over-centre toggle mechanism 38, and a drain valve actuating mechanism 40. The said one end of the float arm 34 is formed with an upper limit pin 42 and a lower limit pin 44, both of which extend in parallel or substantially in parallel with the pivot axis P of the float arm 34.

The over-centre toggle mechanism 38 comprises two arm members 46,48 pivotably interconnected with each other at their first ends 50. The second end 52 of the first arm member 46 is pivotably mounted coaxially with the float arm 34' and extends between the upper and lower limit pins 4244. The second end 52 of the second arm member 48 is pivotably mounted to an interior surface of the housing 12, adjacent the base 22. A spring 54 is incorporated at the second end 52 of the second arm member 48 to bias the over-centre toggle mechanism 38 in a direction in which the drain valve 18 is closed. s

In use, the over-centre toggle mechanism 38 remains in a substantially vertical orientation.

The drain valve actuating mechanism 40 comprises a dog-leg member 56 and a lO connecting member 58 pivotably connected at one end 60 to the dog- leg member 56 midway or substantially midway between the ends 62 of the dog-leg member 56.

The dog-leg member 56 itself is connected at one end 62 to the valve head 30 and is pivotably mounted at the other end 62 coaxially with the float arm 34 and second end 52 of the first arm member 46 of the over-centre toggle mechanism 38.

The second end 64 of the connecting member 58 is connected to the pivotably interconnected first ends 50 of the first and second arm members 46,48 of the over- centre toggle mechanism 38. The second end 64 of the connecting member 58 is formed with a slot 66, and connection to the over-centre toggle mechanism 38 is achieved via a spigot 68 which projects from the over- centre toggle mechanism 38 and which is received in the slot 66 of the connecting member 58. The spigot 68 is thus slidable in the slot 66.

As can be seen from the drawings, the first member 46 of the over-centre toggle mechanism 38, the connecting member 58 of the drain valve actuating mechanism 4O, and the upper part of the dog-leg member 56 of the drain valve actuating mechanism 40 form a parallelogram or substantially parallelogram linkage arrangement.

In use, the condensate collector 10 is located within a boiler body of a condensing boiler assembly (not shown), and is intended to replace a traditional condensate collector having a U-bend trap and/or siphon, or to replace only the U bend trap of a traditional condensate collector. The inlet 14 of the condensate collector is connected to the condensate outlet of a heat exchanger of the boiler assembly, and the outlet 16 is connected to an external drain, typically via a pipe (not shown) which passes through one side of the boiler assembly.

With the condensate collector 10 empty or substantially empty (i.e. with the float 36 positioned on or near the base 22), the over-centre toggle mechanism 38 is biased by the spring 54 to a first position. At this first position, the first arm member 46 of the toggle mechanism 38 is spaced from both the upper and lower limit pins 42,44 of the float arm 34, and the spigot 68 of the toggle mechanism 38 abuts the first end 72 of the slot 66 of the connecting member 58 which is furthest from the point of connection between the connecting member 58 and the dog-leg member 56. This has the effect of resiliently and fluid- tightly biasing the valve head 30 of the drain valve 18 against the valve seat 28, thus preventing the escape of any condensate held in the housing 12.

As condensate collects in the housing 12, the float 36 rises. The upper limit pin 42 is positioned on the float arm 34 so that, as the float 36 rises, the upper limit pin 42 does not immediately contact the first arm member 46 of the toggle mechanism 38. As the float 36 nears the upper surface 20 of the housing 12, the upper limit pin 42 contacts the first arm member 46 of the toggle mechanism 38. As the float 36 continues to rise and enters the float recess 247 the upper limit pin 42 urges the first arm member 46 against the urging force of the spring 54 towards a second position.

As the toggle mechanism 38 moves over centre, i.e. past the position when the longitudinal axes of the first and second arm members 46,48 align, the spigot 68 slides into contact with the other end 74 of the slot 66 of the connecting member 58 The connecting member 58 is therefore urged by the toggle mechanism 38, which causes the dog-leg member 56 to pivot, resulting in the valve head 30 being quickly or rapidly withdrawn from the valve seat 28. The drain valve 18 thus opens with a 'snap' action, allowing the condensate in the housing 12 to drain in a single continuous flow.

Due to the overentre configuration of the toggle mechanism 38 and the fact that the lower limit pin 44 of the float arm 34 is spaced from the first arm member 46 of the toggle mechanism 38, the second position is maintained even as the level of condensate in the housing 12, and consequently the float 36, falls.

As the float 36 approaches the base 22 again, the lower limit pin 44 contacts the first arm member 46 of the toggle mechanism 38, urging it back towards the first position. This urging, in combination with the spring 54 acting on the second arm member 48, results in the toggle mechanism 38 moving or 'snapping' back to the first position with relatively little initial angular displacement of the first arm member 46 by the lower limit pin 44. As a consequence, the dog-leg member 56 is pivoted via the connecting member 58, due to the spigot 68 of the toggle mechanism 38 sliding into contact again with the first end 72 of the slot 66, causing the valve head 30 to quickly or rapidly move back into fluidtight contact with the valve seat 28. This rapid closure of the drain valve 18 results in the flow of condensate from the housing 12 being decisively terminated. As such, little, if any, dripping occurs after closure.

By configuring the opening mechanism 32 to quickly or rapidly open and close the drain valve 18, i.e. having a 'snap' action, the instances of low flow rate, which can also lead to freezing in the drain pipe in particularly severe ambient conditions, are significantly reduced or even eliminated.

The movement of the valve head 30 to open and close the drain valve 18 is in a direction transverse to the flow of condensate through the collector outlet 16. The movement is also transverse to the direction of flow of condensate into the housing 12 through the inlet 14.

The float recess 24 is not essential, but allows a larger float 36 and/or a smaller housing 12 to be used.

The above-described condensate collector 1O is configured purely as an automatic mechanical arrangement. Since the collector has no electronic components, greater reliability in the relatively harsh environment of a boiler assembly can be achieved.

The provision of a solely mechanical drain valve to seal the outlet of the collector is advantageous over the traditional utilisation of a U- bend trap, since it cannot be breached simply by a build up of flue gas pressure in the event of a blockage along the normal flue gas flow path. Even if flue gas does accumulate in the housing, the drain valve is typically closed by the float before the condensate reaches a level at which the outlet becomes open to ambient air. Consequently, flue gas cannot escape.

It is thus possible to provide a boiler condensate collector which, in the event of a flue gas flow path blockage, does not provide a substitute flow path for the flue gas. It is also possible to provide a condensate collector which reduces or eliminates the possibility of drain pipe blockage due to freezing of dripping, or low flow rate, condensate.

The above-described automatic opening and closing condensate collector can be used with any type of condensing boiler assembly. For example, it can be used in either a gas- or oil- fired boiler assembly, and it can be used in a boiler assembly having a single heat exchanger or multiple heat exchangers.

The embodiments described above are given by way of examples only, and modifications will be apparent to persons skilled in the art without departing from the scope of the invention as defined by the appended claims. For example, the housing 12 could be formed from metal, instead of plastics.

Claims

1. A boiler condensate collector comprising a housing, which is receivable in a boiler body of a condensing boiler assembly and which has an inlet for condensate from a heat exchanger of the condensing boiler assembly and an outlet for connection to a drain, and a drain valve which is positioned in or at the outlet of the housing and which opens to drain when condensate in the housing reaches a predetermined level.

2. A boiler condensate collector as claimed in claim 1, wherein the drain valve has an opening mechanism which closes the drain valve using a snap action to reduce or eliminate dripping of condensate from the condensate outlet.

3. A boiler condensate collector as claimed in claim 1 or claim 2, wherein the drain valve has an opening mechanism which opens the drain valve using a snap action to reduce or eliminate low flow rate of condensate from the condensate outlet.

4. A boiler condensate collector as claimed in any one of claims I to 3, wherein the opening mechanism includes a float, the opening mechanism being operated when the float reaches a predetermined position within the housing.

5. A boiler condensate collector as claimed 4 when dependent on claim 2 or claim 3, wherein the opening mechanism further includes a spring-biased over- centre toggle mechanism by which the snap action is achieved.

6. A boiler condensate collector as claimed in claim 5, wherein the overcentre toggle mechanism is operated by a float arm to which the float is attached.

7. A boiler condensate collector as claimed in any one of the preceding claims, wherein the opening mechanism further includes a drain valve actuating mechanism which opens and closes the drain valve.

8. A boiler condensate collector as claimed in claim 7 when dependent on claim S or claim 6, wherein the actuating mechanism is operated by the over-centre toggle mechanism.

9. A boiler condensate collector as claimed in claim 8, wherein the float arm, over-centre toggle mechanism and drain valve actuating mechanism are all pivotable about a common axis.

10. A boiler condensate collector substantially as hereinbefore described with reference to the accompanying drawings.

11. A condensing boiler assembly comprising a boiler condensate collector as claimed in any one of the preceding claims.