GB2059025A - Water heating boiler unit - Google Patents

Abstract

A water heating boiler unit has a conduit 16 located within a water chamber 13 and connected at one end to a burner 26 and at its other end to a flue 27, said conduit 16 extending through an end plate 11 and being connected to the end plate 1 by a resilient mounting 24, 25 so that in use of the boiler the combustion gases flowing along the conduit 16 cause the conduit 16 to oscillate, thereby reducing or preventing a build-up of scale on the conduit 16. <IMAGE>

Description

SPECIFICATION Water heating boiler unit This invention relates to a water heating boiler unit and particularly, but not exclusively to a gas-fired boiler unit.

Water heating boiler units usually suffer from the build-up of scale on the surface of the tubes which are heated by products of combustion and transfer heat to the water.

The build-up of scale reduces the thermal efficiency of the boiler unit and can result in long shut-down periods whilst the boiler is serviced and scale removed.

According to the present invention there is provided a water heating boiler unit having at least one conduit located within a water chamber and connected at one end to a source of combustion and at its other end to a flue, said conduit extending through an end plate of the structure defining the water chamber and being connected to the end plate by a resilient mounting so that in use of the boiler unit the combustion gases flowing along the conduit cause the conduit to oscillate, thereby reducing or preventing a build-up of scale on the conduit.

Preferably the or each conduit is substantially U-shaped in side elevation, the free end of each limb portion of the conduit being connected to said end plate by a said resilient mounting.

Preferably the resilient mounting comprises a ring surrounding and fixed to the conduit, said ring having an annular array of holes extending axially therethrough, each hole being aligned axially with a hole of an annular array of holes provided in the end plate, a fastening bolt extending through each pair of aligned holes, a resilient member provided on each bolt and located between the end plate and a nut provided on the bolt, and a resilient member provided between the end plate and the ring.

An embodiment of the invention will now be described, by way of an example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic perspective view of a boiler unit according to the present invention, Figure 2 is an end view of the boiler unit, Figure 3 is a longitudinal section through the boiler unit, Figure 4 is a side elevation of a conduit through which the combustion gases flow, Figure 5 is an end view of the conduit shown in Fig. 4, and Figure 6 is a section on a larger scale of part of the mounting of the conduit.

The boiler has a cylindrical casing 10 closed at one end by a front end plate 11 and closed at its other end by a rear end plate 1 2.

The casing 10 and end plates 11, 12 define a chamber 1 3 which contains water. Cold water enters the chamber 1 3 through an inlet conduit 14 and hot water is discharged through an outlet conduit 1 5. The casing 10 and plates plates 11, 1 2 are preferably covered with a heat insulation material.

Located within the chamber 1 3 are two conduits 1 6 which extend from and are carried by the front end plate 1 2. Each conduit 16 has two parallel portions 16a and 16b which are interconnected by a transverse portion 16c.

Each parallel portion 1 6a and 1 6b is mounted in the same manner and therefore only one the description of the portion 16a will be described in detail. Secured to the portion 1 6a is a ring 1 7 having a plurality of holes 1 8 extending therethrough, the holes 1 8 all being located on the same pitch diameter. The end plate 11 is provided with a hole 1 9 through which the end portion of the tube portion 16a extends. Surrounding the hole 19 is a circular array of holes 20 which are axially aligned with the holes 18. Extending through each of the aligned holes 1 8 and 20 is a fastening bolt 21 provided with a nut 22 which acts on a washer 23.Provided between the washer 23 and the end plate 11 is a resilient member 24. The ring 1 7 is provided with a groove in which is received a sealing ring 25.

Each tube portion 1 6a is arranged to receive hot combustion gases from a burner 26 mounted on the front plate 11. The burner 26 may be oil or gas fired and fed with air from a fan (not shown).

Each tube portion 1 6 b is arranged to discharge hot combustion gases to a flue 27 mounted on the front plate 11.

A plurality of baffles 28 are provided in the portion 1 6b of each conduit 16. The baffles 28 create turbulence in the gas flow. Such baffles 28 may be as shown and claimed in our United Kingdom Patent No. 1503899.

The mounting of the conduits 1 6 to the front plate 11 in the manner described above enables the conduits 1 6 to expand and contract and each conduit 1 6 in use of the boiler is able to oscillate when the burner 26 is firing.

The vibrations caused by pulsation of the burner 26 within the conduit creates a sound wave which is related to the distance of combustion down the conduit 1 6. This vibration causes the conduit 1 6 to oscillate at a predetermined rate. The oscillation of the conduit 1 6 within the water contained in the chamber 1 3 prevents a build-up of scale on the external surface of the conduit 1 6.

The conduits 1 6 can be coated with a material sold under the trade name XYLAN 1700 which reduces the adherence of scale on the conduits 16. This, coupled with the oscillation and expansion and contraction of the the conduits 1 6 prevents permanent adher- ence and build-up of scale.

The boiler incorporates a scale removal trap which enables the small particles of scale that have been liberated from the heat exchanger tube 1 6 to be moved out of the drain plug of the boiler by flushing through the system.

This incorporates a guillotine type of device (not shown) which is operated by a spanner and tommy bar.

Claims (7)

1. A water heating boiler unit having at least one conduit located within a water chamber and connected at one end to a source of combustion and at its other end to a flue, said conduit extending through an end plate of the structure defining the water chamber and being connected to the end plate by a resilient mounting se that in use of the boiler unit the combustion gases flowing along the conduit cause the conduit to oscillate, thereby reducing or preventing a build-up of scale on the conduit.

2. A boiler unit as claimed in claim 1, in which the or each conduit is substantially Ushaped in side elevation, the free end of each limb portion of the conduit being connected to said end plate by a said resilient mounting.

3. A boiler unit as claimed in claim 2, in which baffles are provided within one limb portion of the conduit to create turbulence in the gases flowing through said portion.

4. A boiler unit as claimed in any preceding claim, in which the resilient mounting comprises a ring surrounding and fixed to the conduit, said ring having an annular array of holes extending axially therethrough, each hole being aligned axially with a hole of an annular array of holes provided in the end plate, a fastening bolt extending through each pair of aligned holes, a resilient member provided on each bolt and located between the end plate and a nut provided on the bolt, and a resilient member provided between the end plate and the ring.

5. A boiler unit as claimed in any preceding claim, in which one end of the or each conduit is connected to a fuel burner and the other end connected to a discharge flue.

6. A boiler unit as claimed in any preceding claim, in which the structure defining the water chamber is provided with a scale removal trap.

7. A water heating boiler unit substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.