[0001] The present invention relates to a pumping unit for a boiler of an installation for
heating and for generating domestic hot water, of the type defined in the preamble
of the appended Claim 1.
[0002] Figure 1 of the appended drawings schematically illustrates a boiler B of a known
type, which comprises a pumping unit indicated as a whole by A. This unit A is connected
between an inlet connector 20 and a primary heat exchanger 21 intended to heat a flow
of water for use in a heating circuit comprising (for example) piping 22 which extends
between an outlet connector 23 and the inlet connector 20, and along which one or
more radiators 24 are interposed. The boiler B further comprises a secondary heat
exchanger 25, of the liquid/liquid type, for example a plate heat exchanger, for transferring
heat from a water flow coming from the primary heat exchanger 21, and flowing in a
pipe 26, to a flow of domestic water in piping 27 which extends between two connectors
28, 29 of the boiler. The connector 28 is intended to be connected to a source of
supply for the plumbing system, for example the mains supply, and the connector 29
can be connected to a tap 30 for supplying heated domestic water.
[0003] The pumping unit A comprises, in a known way, a body 1, made of moulded plastic material
for example, having a first inlet 2 and an outlet 3, for connection to the connector
20 (and therefore to the return pipe of the heating circuit 22, 24) and to the inlet
of the primary heat exchanger 21, respectively. The body 1 also has two further inlets
4 and 5, connected, respectively, to the secondary heat exchanger 25 and to a by-pass
conduit 31 in which a one-way valve 32 can be interposed. This by-pass conduit extends
essentially in parallel with the primary heat exchanger 21, between the outlet of
the latter and the inlet 5 of the pumping unit A.
[0004] A circulation pump 7 and a three-way solenoid valve indicated as a whole by 8 are
provided, in series with each other, between the outlet 3 and the inlet 2 of the body
1 of the pumping unit A. This solenoid valve 8 has an inlet connected to the inlet
connectors 2 and 5 of the body 1, and a further inlet connected to the inlet connector
4 of this body, and thus to the secondary heat exchanger 25.
[0005] In the prior art solution shown in Figure 1, if the connectors 20 and 23 are both
closed while the three-way solenoid valve 8 is in the "heating position" (in which
it connects the inlet 2 to the pump 7, while it disconnects the inlet 4 from this
pump), the circulation of the heating water inside the primary heat exchanger 21 continues
to be provided through the by-pass conduit 31 and the one-way valve 32, if present,
associated therewith. This provides effective protection of the primary heat exchanger
21.
[0006] However, the prior art solution described above has a number of drawbacks. In the
first place, it requires the interconnection of a large number of components, using
a considerable number of plumbing connections. It therefore gives rise to risks of
leakage, and has excessive overall dimensions and cost.
[0007] One object of the present invention is to provide a pumping unit for a boiler of
an installation for heating and for generating domestic hot water, which can overcome
the aforementioned drawbacks of the prior art solutions.
[0008] This and other objects are achieved according to the invention with a pumping unit
whose principal characteristics are defined in the appended Claim 1.
[0009] According to the invention, there is further provided an arrangement for a boiler
of an installation for heating and generating hot sanitary water having the features
of the appended Claim 4.
[0010] Further features and advantages of the invention will become clear from the following
detailed description which is given, purely by way of non-limiting example, with reference
to the appended drawings, in which:
Figure 1, described above, is a partial schematic illustration of a boiler for an
installation for heating and for generating domestic hot water, including a pumping
unit according to the prior art;
Figure 2 is a perspective view of a pumping unit according to the present invention;
Figure 3 is a diagram similar to that of Figure 1, and represents in a schematic and
partial way a boiler for an installation for heating and for generating domestic hot
water, including a pumping unit according to the present invention; and
Figure 4 is a partial perspective view, partially in a section taken along the line
IV-IV of Figure 2.
[0011] In Figures 2 to 4, parts and elements described previously with respect to Figure
1 have been given the same alphabetic symbols and reference numerals as those used
previously.
[0012] With reference to Figure 3 in particular, a pumping unit A according to the invention
is primarily characterized in that the by-pass conduit 31 is also formed inside its
body 1, and in that a one-way valve 32 can also be provided (if required) on the by-pass
conduit and still inside the body 1. The by-pass conduit 31 is substantially in series
with the primary pipe 26 of the secondary heat exchanger 25.
[0013] Because of this feature, the body 1 of the pumping unit A can have a smaller number
of inlet connectors, since it is no longer necessary, in particular, to have the connector
indicated by 5 in Figure 1. A further advantage of the solution according to the invention
lies in the fact that the by-pass conduit 31 and the one-way valve 32, if present,
are incorporated and pre-assembled in the pumping unit A. Consequently there is an
appreciable reduction in the number of plumbing connections required for the assembly
of the boiler B, and therefore a reduction in the risk of leakage.
[0014] The overall dimensions and cost are also substantially reduced.
[0015] As is apparent in the schematic illustration of Figure 3, the by-pass conduit 31
is formed in the body 1 between the second inlet 4 of this body and the inlet (pumping
chamber) of the pump 7. The inlet 4 of the body 1 is coupled to the primary side of
the secondary heat exchanger 25, not in a direct manner, but through a length of pipe
26. This arrangement can also be clearly seen in the detail shown in Figure 4, where
the inlet (pumping chamber) of the pump 7 is indicated by 33.
[0016] It can be seen in Figures 2 and 4 that the solution according to the invention can
be used to produce an extremely compact pumping unit A, with dimensions no greater
than those of a similar pumping unit according to the prior art.
[0017] As an alternative to the embodiment described above, the by-pass conduit 31 can be
formed in the body 1 between the inlets 2 and 4 of the solenoid valve 8, once again
with or without the non-return valve 32.
[0018] As a further alternative, the by-pass conduit can be made in the form of a calibrated
passage which passes through the plug of the solenoid valve 8 to allow a controlled
trickle of liquid.
[0019] In a further variant, in place of a special by-pass conduit, the by-pass function
for the protection of the primary heat exchanger 21 can be provided by the (forced)
energization of the solenoid valve 8 by an associated control unit EU, such that the
inlet 4 is put into communication with the inlet of the pump 7, still inside the body
1.
[0020] Clearly, provided that the principle of the invention is retained, the forms of application
and the details of construction can be varied widely from what has been described
and illustrated purely by way of non-limiting example, without thereby departing from
the scope of protection of the invention as defined by the attached claims.
1. A hydraulic pumping assembly (A) for a boiler (B) of an installation for heating and
generating hot sanitary water, the boiler (B) including a primary heat exchanger (21)
for heating a flow of water for a hydraulic heating circuit (22, 24), a secondary
heat exchanger (25) for transferring heat from a flow of water coming from the primary
heat exchanger (21) to a flow of sanitary water, and a by-pass circuit (31) for the
protection of the primary heat exchanger (21);
the hydraulic pumping assembly (A) comprising
a body (1) with an outlet (3) and a first inlet (2) for connection to said primary
heat exchanger (21) and to a return pipe of said heating circuit (22, 24), respectively,
and with a second inlet (4) for receiving a flow of heating water from said secondary
heat exchanger (25);
between the outlet (3) and the first inlet (2) in said body (1) there being provided
a circulation pump (7) and a three-way electric valve (8), hydraulically in series
with one another, said three-way electrical valve (8) being further connected to said
second inlet (4);
the pumping assembly (A) being characterised in that said by-pass conduit (31) is provided inside said body (1), the by-pass conduit (31)
being provided between the second inlet (4) of said body (1) and an inlet (33) of
said circulation pump (7), or between the second inlet (4) and the first inlet (2)
of said body (1), wherein in said by-pass conduit (31) there is provided a one-direction
hydraulic valve (32), equally provided inside said body (1).
2. An installation for heating and for the generation of warm sanitary water, comprising
a boiler (B) including a hydraulic pumping assembly (A) according to claim 1.
3. An installation according to Claim 2, characterised in that said by-pass conduit (31) is provided as a seeping conduit in the obturator or shutter
of said electric valve (8).
4. An arrangement for a boiler (B) of an installation for heating and generating hot
sanitary water, the boiler (B) including a primary heat exchanger (21) for heating
a flow of water for a hydraulic heating circuit (22, 24) and a by-pass circuit (31)
for the protection of the primary heat exchanger (21);
the arrangement including a secondary heat exchanger (25) for transferring heat from
a flow of water coming from the primary heat exchanger (21) to a flow of sanitary
water, and a hydraulic pumping assembly (A) comprising
a body (1) with an outlet (3) and a first inlet (2) for connection to said primary
heat exchanger (21) and to a return pipe of said heating circuit (22, 24), respectively,
and with a second inlet (4) connected to said secondary heat exchanger (25) for receiving
a flow of heating water from said secondary heat exchanger (25);
between the outlet (3) and the first inlet (2) in said body (1) there being provided
a circulation pump (7) and a three-way electric valve (8), hydraulically in series
with one another, said three-way electrical valve (8) being further connected to said
second inlet (4);
the arrangement being characterised in that said by-pass conduit (31) is provided inside said body (1), the by-pass conduit (31)
being provided between the second inlet (4) of said body (1) and an inlet (33) of
said circulation pump (7), or between the second inlet (4) and the first inlet (2)
of said body (1) .
5. An installation for heating and for the generation of warm sanitary water, comprising
a boiler (B) including an arrangement according to claim 4.
6. An installation according to Claim 5, characterised in that said by-pass conduit (31) is provided as a seeping conduit in the obturator or shutter
of said electric valve (8).
7. An installation according to any of claims 5 to 6, characterised in that in said by-pass conduit (31) there is provided a one-direction hydraulic valve (32),
equally provided inside said body (1).