GB2482169A

GB2482169A - Apparatus particularly for use in dosing a central heating system

Info

Publication number: GB2482169A
Application number: GB1012322.2A
Authority: GB
Inventors: Kevin Abbott
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-07-22
Filing date: 2010-07-22
Publication date: 2012-01-25
Also published as: GB201012322D0

Abstract

The apparatus comprises a cylindrical vessel 1 having an inlet pipe and an outlet pipe, and a piston 4 located within the vessel and disposed between the inlet and outlet to define an inlet side and an outlet side of the vessel, the piston being movable within the vessel between a first position that is remote from the outlet and a second position that is near to the outlet. In the first position, the piston forms a seal between the inlet side and outlet side of the vessel, such that fluid in the inlet side of the vessel cannot reach the outlet side of the vessel, the seal being maintained until the piston reaches the second position, wherein a bypass passage through or around the piston permits fluid in the inlet side of the vessel to reach the outlet side of the vessel. The apparatus may be used to dose central heating systems with treatment chemicals such as rust inhibitors or anti-freeze, although the apparatus may additionally be used for scientific or industrial laboratory systems, medical systems or automotive systems.

Description

Fluid Flow System Chemicals Dosing Apparatus

Field of the Invention

The present invention concerns improvements in and relating to apparatus for dosing a fluid-filled, eg water-filled, system with a dose of one or more chemicals / treatment fluid. The invention may have applicability to treating central heating systems with rust inhibitor liquids or applicability to a wide range of other uses including but not limited to treating fluid-filled systems as diverse as scientific or industrial laboratory flow systems, medical systems such as drips! circulatory feeds for patients or automotive! transport or other industrial flow systems wherever there is a need for dosing the fluid in the system with treatment fluids! chemicals (ie fluid of a type or content different from the fluid normally flowing in the system) from time-to-time.

Background to the Invention

Modern central heating systems, and especially pressurised! sealed central heating systems, require treatment with anti-freeze, rust inhibitor chemicals and! or descaling or lirriescale inhibiting chemicals or other chemicals on a regular basis to ensure good maintenance of the system.

In general this is done by service engineers! plumbers who carry out regular site visits to premises with such systems. The specialized nature of the task when dealing with pressurised! sealed central heating systems has lead to development of specialized apparatus and procedures for the purpose and there are a number of relevant patent applications and patents.

Addition of rust inhibitor chemicals to non-pressurised systems is the subject of patent applications and patents from twenty years ago and earlier, as exemplified by UK patent GB 2162164B and its citations.

GB 2162164B concerns use of a sealed vessel to receive the rust inhibitor. A volume of water is added into the vessel as diluent! flushing medium. The vessel has an inlet for pressurised air from a separate pump such as a bicycle pump to drive the chemical-laden fluid into a radiator of the non-pressurised central heating system via a bleed valve of the radiator. This approach introduces air into the system but this is not a major problem for the non-pressurised system since the air can simply be bled back out subsequently. The process is relatively risk-free and can be carried out by a home-owner. It does not need to be done by a professional.

When dealing with a pressurised central heating system the process is made substantially more difficult by the very fact of pressurization. Some have sought to address the problem by introducing the dosing vessel into the circuit of the pressurised central heating system between the cold water supply pipe and central heating return pipe of the system so that the inflowing cold water swirls in the vessel and carries the chemical up from the floor of the vessel into the central heating system. An example of this is disclosed in UK patent application GB2442008A where a pair of hoses is provided one to couple the vessel to the cold water supply pipe and the other to couple the vessel to the central heating return pipe.

The arrangement in GB2442008A enables dosing to be carried out relatively safely since the hoses are coupled in place and valves to the hoses are only opened when the circuit through the vessel is water-tight.

However, the delivery of the water and chemicals is inefficient and relies on a sufficient flow of water to have passed through the vessel to transfer substantially the whole dose of chemical into the system before the vessel and hoses can be uncoupled from the system. This may entail twenty or more litres of water having to pass through a litre-sized vessel before the plumber! service-engineer can be reasonably sure that the chemical has been substantially fully passed! flushed into the system. For a plumber! service-engineer on the clock this can be a significant waste of his time (and the client's money). Furthermore, this can be wasteful of water and incur extra water meterage charges for the customer.

It is an object of the present invention to provide an improved method and apparatus for dosing a fluid! water system such as, for example, a s central heating system, or a medical drip or any other flow system with one or more chemicals! treatment fluid and which allows rapid and substantially accurate dosing with minimal usage of water! fluid to flush the chemicals! treatment fluid into the system.

Sum mary of the Invention According to a first aspect of the present invention there is provided apparatus for dosing a fluid! water-filled system with one or more treatment chemicals! fluid, the apparatus comprising: a vessel; an inlet pipe or hose and an outlet pipe or hose for coupling to the system so that fluid! water may flow into the vessel and fluid from the vessel may flow from within the vessel out of the vessel and into the system, the vessel having a piston therewithin and the vessel wall defining a cylinder in which the piston moves under pressure of incoming fluid from a first position at which the vessel contains fluid to be dispensed to a second position corresponding to substantially complete emptying of the vessel, wherein the apparatus has a bypass passage through or around the piston that opens when the piston substantially reaches the second position so that fluid! water from the system may flow passed the piston when the piston is at the second position. This arrangement allows the apparatus to safely and relatively accurately and rapidly dispense all of the chemical content of the vessel into the system. The opening of the passage prevents back pressure build up when the piston has travelled to its second position and ensures that the vessel may be fully flushed by the normal inflowing system fluid! water subsequently.

Preferably the vessel allows viewing of the movement of the piston. It is preferably a transparent vessel or has a transparent portion of wall to allow the user to view the piston moving into the second position. A pressure gauge may also be provided to monitor the pressure in the vessel and suitably is mounted on the exterior of the vessel and coupled to the interior of the vessel by a conduit. Preferably the pressure gauge is coupled to the interior of the vessel on the side of the piston where fluid flows into the vessel. The gauge provides warning if there is any obstruction and also allows the user to check that the device is operating correctly and with a desired level of pressure of the fluid in the vessel. In general the pressure will correspond to that of the water supply into the is vessel but may be adjusted upwardly or downwardly if required, to give a faster or slower rate of flushing for optimal flushing! dosing effectiveness.

The pressure or rate of flushing may be adjusted before use by the selection of the tightness of friction fit of the piston. The piston suitably has elastomeric 0-rings I sealing rings to seal the circumference of the piston to the wall of the cylinder of the vessel.

Preferably the vessel is formed with a hollow central cylindrical body that is initially open at each end and has a first end plate and a second end plate mounted thereto each to sealingly close off a respective open end, at least one of which is readily demountable following use to allow for ease of maintenance. Suitably the demountable plate is bolted in place to the cylindrical body. In the preferred embodiment the first end plate is bolted to the second end plate, sandwiching and clamping the cylindrical body therebetween.

The dosing device provides a new, easier way of adding chemicals into, for example, a sealed central heating system. For the domestic market it is suitably provided with a vessel of capacity corresponding to the commonest commercial size of chemicals pack for treating domestic sealed central heating systems. Currently this is a 1 litre capacity. For the commercial market, ie for larger premises such as schools, hospitals, offices and industrial premises, it is suitably provided with a larger vessel that may be of the order of 5 litres in capacity or larger and suitably corresponds to the larger sizes of chemicals packs available on the market or to multiples of available pack sizes. If a user only needs to add 1 litre of inhibitor fluid there is no need for draining the central heating system.

The dosing device can couple into the filling loop of the central heating system and the pressure of the water in the system pushes the liquid chemicals ahead of it, undiluted, into the central heating system. The user has complete control of the amount of chemical they add to the system. is

Once the full content of the vessel has entered the system the device then lets the water flow through the vessel, through or passed the piston and into the system as desired, giving the user full control the whole time unlike the existing prior art devices. With the present device the user can see all of the chemicals going into the system and can control substantially exactly how much is going in. There need be no residual chemical left in the vessel after the initial flush operation, unlike prior art in-line flushing systems such as that disclosed in GB2442008A, where the volume of liquid left in the vessel when it is uncoupled may contain some of the chemical.

For other fluidic systems, circulatory or not, as diverse as: eg medical drips where the treatment chemical! fluid might be a chemical (drug) for treatment of the patient; or for use in industrial fluid systems such as eg fuel systems or fluid distribution systems or food manufacturing systems, the treatment chemical! fluid might be for lubrication or anti-freeze or indeed any other need intrinsic or external to the system.

Brief Description of the Drawings

The present invention will now be more particularly described by way of example, with reference to the accompanying drawings, wherein; Figure 1 is a right side perspective view of the vessel of the device; Figure 2 is a frontal perspective view of the vessel of the device; io Figure 3 is a left side perspective view of the vessel of the device; Figure 4 is a left side perspective view of the vessel of the device similar to Figure 3 but showing a pressure gauge installed thereon; Figure 5 is a schematic sectional view of the vessel of the device showing the two stage structure of the piston, with the piston in its initial position; is Figure 6 is a schematic sectional view corresponding to Figure 5 but showing the piston moved to its second! terminal position and the two stages of the piston shifted a small spacing apart to open up a flow passage through the piston; and Figure 7 is a schematic sectional view similar to Figure 5 but showing a variant! second embodiment in which the bypass passage to bypass the piston is provided as grooves in the cylinder wall of the vessel.

Description of the Preferred Embodiments

Referring to Figures 1 to 3, the device comprises a vessel 1, as shown, with a transparent tubular cylindrical body la that is blanked off at top and bottom ends by respective end plates 2 that are suitably ABS, acrylic or nylon mouldings. Each end plate 2 is configured to project into the respective vessel end as a plug that is sealed by a respective 0 ring elastomeric seal 3 to the inner wall of the cylindrical body la of the vessel.

A short cylindrical! discoidal piston 4, preferably moulded of ABS, acrylic or nylon, is slidingly received within the tubular cylindrical body la to be able to move up and down from an initial! first position at the floor of the tubular cylindrical body la to a second/terminal position at the upper end thereof and in the process drive any fluid within the vessel up and out from the vessel.

The upper end plate 2 has a central circular fill opening 2a with a large screw-threaded cap 2b that is openable to introduce liquid treatment chemicals straight from a commercially available pack into the vessel 1. In most cases the treatment chemical is an aqueous solution of rust inhibitor or other chemical and does not require preliminary liquidifying, mixing or dilution. A full litre of such fluid may be poured into the vessel, filling the litre-capacity holding chamber above the piston 4.

Other than the fill opening 2a, the upper end of the vessel 1 and the upper end plate 2 have no other inflow openings. An outflow opening and is passage is provided in the upper end plate 2 in a shelf 2c that projects radially outwardly and which has a fixed length of pipe 5 extending down to a tap 5a and exit coupling 5b at the free lower end of the pipe 5. The upper plate 2 of the vessel projects radially outwardly and holds the pipe 5 away from the body 1 a of the vessel.

The device also comprises a pair of coupling hoses (not shown) to couple the vessel into a central heating system, suitably between the cold water supply pipe of the central heating system and the return pipe of the central heating system such as is done in the prior art and illustrated inter alia in GB 2442008A. Exit coupling Sb at the free lower end of the outflow pipe S comprises a screw thread on the outside diameter of the pipe S to which an end of one of the pair of hoses may be attached.

The base plate 1 b of the vessel 1 also has a shelf 2c that projects radially outwardly and this incorporates a short length of feed pipe 6 that runs from an inflow opening into the lower interior of the vessel 1 a below the piston 4 to a tap! hand operated valve 6a and inlet coupling 6b. Inlet coupling 6b at the free lower end of the inflow pipe 6 comprises a screw thread on the outside diameter of the pipe 6 to which an end of one of the pair of hoses may be attached and where the other end of the hose is attached to the water supply pipe for the central heating system.

Each end plate 2 is readily demountable from the tubular cylindrical body la following use to allow for ease of maintenance. The upper end plate 2 is bolted to the lower end plate 2 by bolts 7 that extend up the full height of the body la and the cylindrical body la is thus sandwiched and clamped between the respective end plates 2. The unit as a whole is, in the illustrated form, adapted to stand upright on bun-shaped feet at the bottom of the lower plate 2. However, the device may be used in a range of orientations in principle, even inverted, and not simply oriented upright with the water in-feed at the bottom and outflow at the top. Nevertheless is the illustrated arrangement suits introduction of the chemical by pouring in from above and is, therefore, the preferred configuration.

As shown in Figure 4, a pressure gauge G may be coupled to a valved conduit outlet to communicate with the interior of vessel la and provide reading of the fluid pressure within the vessel la, suitably being the pressure at the water supply! inflow side of the piston 4.

Referring now to Figures 5 and 6, the piston 4 has an upper stage 4a and a lower stage 4b. The upper stage 4a is of short cylindrical! discoidal form and the lower stage 4b has a thinner discoidal form. An elastomeric 0-ring 4c is provided in an annular groove around the outside circumferential surface of the piston upper stage 4a to provide a seal against the bore of the vessel cylindrical body la. The upper stage 4a has a broad circular central passage 8 extending up through it to allow water W that has entered the vessel 1 from the central heating system water supply to be expelled through the body of the piston 4 but only when the piston 4 has substantially reached the second position adjacent the upper end of the vessel 1.

The lower stage 4b of the piston 4 effectively functions as a valve that is moved away from the upper stage 4a by spigots/plungers! actuating mandrels 7 on the lower stage 4b landing on shoulders or the underside of the upper end of the vessel! upper plate 2 while the upper stage 4a continues to move upwardly a small distance. This opens up access to the central passage 8 in the upper stage 4a of the piston 4. The lower stage! io valve 4b is spring-loaded by a respective spring S on each spigot/plunger 7 so as to be normally biased to the valve-closed state As an alternative to this spring-loaded valve arrangement, one or more internal longitudinal grooves might be machined or otherwise formed in the is vessel's tubular cylindrical body la at the outlet end, as per the second variant! embodiment shown in Figure 7, so that as the piston 4 moves against the upper plate 2 the grooves allow the mains water to pass across the piston 4 circumferential surface and flow over the 0-ring seal 4c. When such a configuration is used a drain valve would generally be necessary in the inlet end plate! end cap 2 so that the piston 4 may be returned for refilling of the apparatus.

Operating sequence: The filler cap 2b is removed and a rod is inserted through the filler cap 2b hole 2a to press against the centre of the piston 4. This pushes against and opens the spring loaded valve 4b allowing the piston 4 to be pushed down against the bottom plate! end cap 2. Any water in the apparatus is now poured out. The desired chemical additive is poured through the filler hole 2a. The filler cap 2b is screwed back in place and the outlet tap! valve 5a is closed. The inlet tap! valve 5b is then closed too and a mains water- connected hose is connected to the inlet coupling 6b and heating system-connected hose is connected to the outlet coupling 5b. The inlet tap! valve 6a is then opened allowing mains water into the cylinder la.

As the pressurised mains water flows into the vessel 1, the piston 4 is pushed towards the upper plate 2 forcing the chemical additive into the heating system. At this stage the chemical additive is separated from the mains water by the piston 4. As the piston 4 reaches the outlet end cap! upper plate 2 the three spigots 7 on the piston valve 4b contact the outlet end cap! upper plate 2 and open the valve 4b allowing mains water to io flush the residue of chemical additive into the heating system. The inlet tap! valve 6a can now be used to reinstate the correct pressure in the system. The inlet and outlet valves 5a, 6a are then closed and the apparatus decoupled and removed from the system. The piston 4 is returned to its position against the inlet end cap! bottom plate 2 and the is water in the cylinder la is emptied. As can thus be appreciated, this whole process is very quick as compared to the prior art and considerably more easy to control and accurate, improving dose usage and operator time and costs. ii

Claims

Claims 1. Apparatus for dosing a fluid! water flow system with one or more treatment chemicals, the apparatus comprising: a vessel; an inlet s pipe or hose and an outlet pipe or hose for coupling to the system so that fluid! water from the system may flow into the vessel and fluid from the vessel may flow from within the vessel out of the vessel and into the system, the vessel having a piston therewithin and the vessel wall defining a cylinder in which the piston moves under io pressure of incoming fluid from a first position at which the vessel contains fluid to be dispensed to a second position corresponding to substantially complete emptying of the vessel, wherein the apparatus has a bypass passage through or around the piston that opens when the piston substantially reaches the second position so that fluid! is water from the system may flow passed the piston when the piston is at the second position to flush the vessel.
2. Apparatus as claimed in claim 1, wherein the bypass passage extends through the piston and has a valve member that is opened by a plunger! operating mandrel in the piston that moves within the piston to push the valve open when the plunger! operating mandrel abuts a shoulder at or near the second position in the vessel.
3. Apparatus as claimed in claim 1 or 2, wherein the vessel is a transparent vessel or has a transparent portion of wall to allow the user to view the piston moving into the second position.
4. Apparatus as claimed in any preceding claim, wherein a pressure gauge is provided mounted on the exterior of the vessel and coupled to the interior of the vessel by a conduit to monitor the pressure in the vessel.
5. Apparatus as claimed in claim 4, wherein the pressure gauge is coupled to the interior of the vessel on the side of the piston where fluid flows into the vessel.
6. Apparatus as claimed in any preceding claim, wherein the vessel is formed with a hollow central cylindrical body that is initially open at each end and has a first end plate and a second end plate mounted thereto each to sealingly close off a respective open end, at least one of which is readily demountable following use to allow for ease of maintenance.
7. Apparatus as claimed in claim 6, wherein the demountable plate is bolted in place to the cylindrical body.
8. Apparatus as claimed in claim 7, wherein the first end plate is bolted to the second end plate sandwiching and clamping the cylindrical body therebetween.
9. Apparatus as claimed in any preceding claim, wherein the bypass passage comprises one or more internal longitudinal grooves! channels in the wall of the vessel's tubular cylindrical body at the outlet end so that as the piston moves against the upper plate the grooves! channels allow the mains water to pass across the piston circumferential surface
10. Apparatus as hereinbefore described with reference to any suitable combination of the accompanying drawings.