Patent Description:
As illustrated in prior art <FIG> and <FIG> a conventional pressurised heating systems includes a boiler or furnace <NUM> in line with heating circuit pipe <NUM>. The boiler needs to be filled from a pressurised water source such as a mains water supply pipe <NUM>. To do this the mains water supply pipe <NUM> may be provided with an inlet valve <NUM> attached by a compression fitting. The inlet valve may be a stop or isolation valve. One inlet end of a plain hose <NUM> is connected by means of a BSP threaded coupling to the inlet valve <NUM>. The heating circuit pipe <NUM> is provided with a spur on to which an outlet valve <NUM> is mounted by a compression coupling. The outlet valve is preferably a stop or isolation valve. The outlet end of the hose <NUM> is then connected to the outlet valve <NUM> by a threaded coupling (step S1 in <FIG>).

To charge the heating circuit the valves <NUM> and <NUM> are then opened (step S1. <NUM>) and water is allowed to flow into the heating circuit until a pressure gauge <NUM> indicates a specified circuit pressure is reached (S1. A check valve may be provided, preferably in one or more of the isolation valves, to prevent leakage of water back out of the pressurised circuit.

When the circuit is charged according to the system specifications the valves <NUM> and <NUM> should be closed (S1. <NUM>) and the hose <NUM> removed (S1. <NUM>) to ensure that there is no connection between the heating circuit <NUM> and mains supply pipe <NUM>. The filling hose <NUM> should be left in close proximity to the boiler <NUM> to provide for subsequent system charging.

It is a frequent occurrence that boilers are damaged by an inexperienced or careless user leaving the filling device (filling loop) in place and the valves <NUM>, <NUM> open, so over pressurising the system or allowing mains water to circulate within the heating circuit. Water in the heating circuit in accordance with good practice should be treated with anti-oxidising and anti-scaling agents. If the filling device is left in place untreated water circulates in the heating system accelerating corrosion and causing rapid and severe scaling with consequent premature failure of the boiler. Experience shows that the boiler failures can be sufficiently severe to require total replacement of the boiler.

The applicant perceives a demand for a filling device which may be able to:.

reliably and safely be operated by an unqualified operative such as the end user.

The prior art devices to prevent this situation are complex devices which admit water into the heating circuit on a periodic basis to maintain the pressure.

<CIT> discloses an apparatus for controlling the pressure of a heating fluid within a central heating system or for controlling the flow of heating fluid into a central heating system. The apparatus comprises an inlet, for connection to a supply of heating fluid, and an outlet, for connection to a heating system. A pressure sensor is arranged to sense the heating fluid pressure within the central heating system. A flow sensor is arranged to sense the volume of heating fluid flowing between the inlet and the outlet. A flow control valve controls the flow of heating fluid from the inlet to the outlet. The flow control valve is operatively connected to the pressure sensor and is arranged to open when the sensed pressure falls below a first predetermined pressure and close when the sensed pressure rises above a second predetermined pressure. Alternatively, the flow control valve is operatively connected to the flow sensor and is arranged to close once a predetermined volume of heating fluid has flowed. A self-bleeding radiator valve comprising a filter arranged to inhibit particulate matter from interfering with the operation of the valve is disclosed. A filtration device for a central heating system, preferably comprising a magnetic particle filter, is also disclosed.

This prior art device of <CIT> provides a complex solution to the problem, comprising a pressure and/or flow sensor to control filling of the heating system by electronic means. As such it is over-complicated and costly for standard domestic use.

<CIT> discloses a water feed controller which can provide for the addition of a preset fixed amount of water to be added after a low water condition is removed. This system provides for a preset fixed amount of water to be added to a boiler above the amount which triggers the low water condition. This generally inhibits excess cycling from the boiler operating at its minimum safe water level as well as inhibiting overfilling of the boiler. Further, there is discussed a water feed controller which can measure the amount of water added over a prior predetermined period (such as <NUM> days) which serves as a floating window of time so that a leak or other condition resulting in overly frequent filling can be detected quickly.

<CIT> discloses: A water feed controller for a boiler, the controller comprising: electronics for monitoring the signal from a low water cut-off (LWCO); electronics for opening and closing a water path; and a processor; wherein when said electronics for monitoring detect a low water signal from said LWCO, said processor initiates opening of said water path to allow water to flow into said boiler; wherein said water path remains open until said LWCO ceases signalling a low water condition; and wherein said processor allows said water path to remain open after said LWCO ceases signalling said low water condition, so a preset fixed amount of water is added into said boiler after said LWCO ceases signalling said low water condition.

Again, these are complex electronic devices, over-specified for standard domestic use and not useful or easy to retrofit to existing boiler installations.

<CIT> discloses: A fluid source e.g. a mains water supply is connected to a fluid user system such as a combination boiler by means including a non-return valve unit, a flow regulator and pipework for connecting the valve unit and flow regulator. The non-return valve allows fluid flow to the fluid user system but prevents reverse fluid flow from the user system to the fluid source. The check valve unit may have an outlet portion permanently connected to the boiler and a conical inlet passage in which a flexible pipe may be held manually during top-up of the boiler. The unit may include two identical valve stems. This device is a standard filling loop device, without a fail-safe mechanism.

<CIT> discloses a filling loop device for a pressurized heating system comprising: means defining a fluid passage having an inlet port connectable to a fluid supply and an outlet port connectable to a heating system fluid circuit; and a dead man valve interposed in the passage between the inlet port and the outlet port, said dead man valve biased to a normally closed condition to shut off fluid flow through the channel in either direction when unattended, and manually operable to an open condition to permit fluid to flow from the inlet port to the outlet port.

According to the present invention there is provided a filling device for a pressurised heating system as defined in claim <NUM>.

The fluid passage may be provided by a length of pipe, flexible hose or via a channel in a mono-block. The inlet and outlet ports may be provided by any conventional coupling including at least: threaded BSP and compression couplings.

The dead-man valve is a valve which is biased to the closed condition and manually operable by an actuator to switch to the open condition. Consequently, on releasing the actuator the valve closes. Therefore, the valve cannot be left unattended in an open condition. A preferred version of the dead-man valve has a pushbutton actuator biased by a spring to the closed condition. The button must be held in the depressed condition to enable fluid to flow through the push button valve.

A push button valve may be vulnerable to jamming open by abusive users, for example by wrapping with tape, consequently actuators such as a spring biased twist grip or other less easily jammed configurations may be preferred.

To ensure there is no backflow from the boiler circuit to the mains water, a one way or check valve is connected such that flow from the inlet to the outlet connector is allowed while the reverse flow is prevented. Single check valves may be vulnerable to reverse flow leakage to prevent which a double check valve may be provided.

A second isolation valve may be connected to the check valve.

A check valve and an isolation valve may be provided in the same housing.

In some embodiments the device comprises, connected in order along the flow pathway: a <NUM> inlet compression to <NUM> ball valve, an <NUM> push button water valve, a <NUM> to <NUM> adapter, a <NUM> flexible filling link comprising a metal braided hose and a <NUM> double check ball valve.

In this way the device provides a means to fill a pressurised heating circuit from a pressurised water source such as a mains water supply, the device being connectable in place of a standard filling loop as known in the art. The use of the push button valve in the fluid pathway means that it is impossible to leave the filling loop in place and open, so avoiding accidental damage to the heating boiler.

It will be understood that the flexible tubing portion may have a range of lengths to suit the configuration of the boiler installation, and that the connector types are not limited to any specific size and the device may be produced with chosen connector sizes to suit the installation.

The device can also include a pressure regulator pre-set to deliver fluid to the outlet at a pressure compatible with the operation of the boiler. This facilitates use by non-technical untrained or sight disabled users who may misread the pressure gauge and charge the heating system to excessive or inadequate pressure.

Embodiments of a filling loop device for charging a pressurised heating circuit according to the present invention, will now be described, by way of example only, with reference to the accompanying illustrative drawings, in which:.

Features common to the prior art of <FIG> are referenced with the same numerals. Thus, <FIG> shows a boiler or furnace <NUM> plumbed into a heating circuit to circulate hot water through a pressurised heating circuit pipe <NUM>.

An inlet valve <NUM> is coupled to a terminus of the mains water pipe <NUM> by means of an inlet connector <NUM>. In this case the inlet connector <NUM> is a conventional compression coupling; however other known forms of coupling including press fit, cement or solder may be employed. The coupling <NUM> couples an isolation valve <NUM> to the end of the mains water pipe <NUM>.

A dead man valve is provided by a push button valve <NUM> configured to open the fluid flow pathway when the push button <NUM> is pushed and thereby displaces a spool against a bias to open a passage through the valve. When the button is released the bias displaces the spool and button to close the fluid passage. In the embodiment shown the push button valve <NUM> has an upstream port adapted to be coupled to a downstream port of the isolation valve <NUM> by means of a BSP threaded coupling.

A downstream port 14d of the push button valve <NUM> is coupled to a flexible tubing portion (hose) <NUM> to provide fluid communication with the outlet valve <NUM>. The outlet valve <NUM> has a housing <NUM> and includes an isolation valve <NUM> which includes a check valve <NUM>, connected such that flow from the inlet <NUM> to the outlet valve is allowed while reverse flow is prevented. The outlet valve <NUM> is coupled to a spur off the heating circuit pipe by means of a compression coupling outlet connector <NUM>. In some embodiments the check valve in the outlet valve <NUM> is a double check valve to add reliability.

<FIG> shows a sectional detail of the push button valve <NUM> with the button depressed. The push button valve <NUM> has a casing 14a with a fluid passage 14b communicating a female threaded inlet port 14c and outlet port 14d. The passage 14b is intersected by a spool chamber 14e containing a spool 14f. The spool 14f is in this case cylindrical. Anti-rotating means (not shown) may be provided to prevent the spool from rotating around its axis. Such means may include a tongued washer, located in nut 15a and engaging a groove in the stem 15b of the push button.

The anti-rotating means ensures that a through passage <NUM> extending diametrically through the spool 14f is aligned with the passage 14b to facilitate the passage of water through the valve when the pushbutton is depressed. A compression spring <NUM> is arranged to urge the spool 14f up into a condition where a lower part <NUM> of the spool obstructs the passage 14b as can be seen in <FIG>.

An "O" ring <NUM>' encircles the spool above the upper part, a middle "O" ring <NUM>" encircles the spool between the upper and lower part and a lower "O" ring encircles the spool at the bottom of the lower part. The "O" rings provide a fluid sealing bearing surface for the spool in the cylindrical spool chamber. <FIG> is a flow chart showing the method of using the device of the first embodiment. The inlet valve <NUM> and outlet valve <NUM> will be installed with the heating system and will remain in place on the mains supply <NUM> and heating circuit spur 2a as in the conventional prior art arrangement.

In step <NUM> the fill loop device is coupled between the inlet and outlet valves <NUM> and <NUM> to provide a channel for the passage of mains water. At step <NUM> the isolation valves <NUM> and <NUM> are opened. At step <NUM> the press button of the dead-man valve is depressed thereby opening a passage for the flow of mains water from the mains pipe <NUM> to the heating circuit spur 2a. This pressurises the heating circuit <NUM> and the pressure is read at step <NUM> from the pressure gauge <NUM> by the user until a manufacturer specified pressure is reached. When the specified pressure is reached the press button valve is released at step <NUM>. The isolation valves <NUM> and <NUM> should then be closed at step <NUM>. Conveniently the filling loop may then be left in place at step S2. <NUM> since there is no possibility of water flow through the filling loop device so long as the valves function correctly. Even if step <NUM> is overlooked there is little risk of water flow into the heating circuit and less of water flow from the heating circuit into the mains supply. In this first embodiment the device comprises, connected in order along the flow pathway: a <NUM> inlet compression to <NUM> ball valve <NUM>, an <NUM> push button water valve <NUM>, a <NUM> to <NUM> adapter <NUM>, a <NUM> flexible filling link comprising a metal braided hose <NUM> and a <NUM> combined double check and ball valve <NUM>.

The second embodiment of the fill loop device is generally similar to the first and corresponding components are identified with similar numerals. Accordingly, only the differences will be described. As can best be seen in <FIG> and <FIG> the filling loop device includes a governor or pressure regulating valve <NUM> in series with the press button valve <NUM>. The pressure regulating valve <NUM> is set to limit the maximum water supply pressure at the outlet <NUM> of the filling loop device to correspond to the specified maximum pressure for the boiler <NUM>. As a result, an inexperienced or untrained user cannot over pressurise the system and thereby cause damage.

A further modification of the second embodiment is most readily apparent from <FIG>. This addresses the issue of the isolation valve <NUM> being incorrectly left open and permitting backflow to the press valve <NUM> even against the check valve <NUM>. Against this eventuality a drain passage <NUM> is formed in the lower part of the spool and arranged to align with the outlet port. The drain passage <NUM> is isolated from the through passage by a barrier 14p, and the middle "O" ring <NUM>". The drain passage communicates with a lower part of the spool chamber and hence to a drain port 14j is provided in the body of the press valve <NUM>. The drain port is conveniently formed by drilling a bore <NUM> through the base 14n of the spool chamber. Since the lower part of the spool chamber is then open to air this creates an air gap between the inlet port and the outlet port. A hollow nipple 14o may be formed on the spool chamber base in communication with the bore <NUM> to which a hose may be attached. This allows water flowing back into the press valve (from the right in <FIG>), to flow through a drain port <NUM> formed in a bottom portion of the spool 14f and to drain out through the drain port 14j.

<FIG> illustrates an alternative embodiment in which the spring 14e' shown in ghosted lines, is located around the press button stem to act between the press button and the valve nut 15b.

Claim 1:
A filling loop device for a pressurized heating system comprising:
means comprising a dead man valve (<NUM>) defining a fluid passage (14b) having, an inlet port (14c) connectable to a fluid supply and an outlet port (14d) connectable to a heating system fluid circuit; said dead man valve (<NUM>) biased to a normally closed condition to shut off fluid flow through the fluid passage (14b) in either direction when unattended, and manually operable to an open condition to permit fluid to flow from the inlet port to the outlet port;
said dead man valve (<NUM>) having:
a casing (14a) providing the fluid passage (14b) with the inlet port, the outlet port and, a spool chamber (14e);
a spool (14f) slidably housed in the spool chamber (14e), said spool including a through passage (<NUM>) capable of communicating the inlet port (14c) and outlet port (14d) for fluid flow therebetween when manually operated, and
bias means (<NUM>) to urge the spool (14f) to the closed condition so that a lower part (<NUM>) of the spool (14f) obstructs the fluid passage (14b) to shut off fluid flow through the inlet port (14c), and
characterised in that a drain passage is formed in the lower part of the spool (14f) isolated from the fluid passage to communicate between the outlet port and a drain port (14j) formed in the lower part of the spool chamber (14e) when the bias means (<NUM>) displaces the spool (14f) to the closed condition.