GB2184815A

GB2184815A - Water-actuated controller

Info

Publication number: GB2184815A
Application number: GB08629319A
Authority: GB
Inventors: Herbert Haas; Wolfgang Mattiske; Heinz-Peter Friedrich
Original assignee: Joh Vaillant GmbH and Co
Current assignee: Vaillant GmbH
Priority date: 1985-12-10
Filing date: 1986-12-08
Publication date: 1987-07-01
Also published as: IT8622620A0; GB8629319D0; DE3641317A1; IT8622620A1; NL8603116A; IT1199726B; DE3641317C2; FR2591320B1; BE905878A; GB2184815B; FR2591320A1; CH672672A5

Abstract

A water-actuated controller (7), Fig. 1, for use with a water heater which is operated with gas, oil or electric power, comprises a housing (6) to which a water inlet line (8) and a water outlet line (9) are connected, a diaphragm (12)-controlled valve in inlet (8) and a venturi nozzle (19) connected between outlet (9) and a pressure chamber (15) on one side of the diaphragm (12) and having its throat communicating via a line 20 with a pressure chamber (14) on the other side of the diaphragm (12), venturi nozzle (19) being by-passed by a spring (23)-loaded, valve (21/22), which has a valve member (22) that is controlled by an adjustable stop (24) which limits the maximum opening of the valve (21/22). The valve (21, 22), Fig. 2, comprises a stepped bore (30) threadedly (33) mounting a sleeve (32), the sleeve threadedly (38) mounting an axially adjustable shaft (37) rotatable by a handle (25), said shaft having a cavity (39) defined by an undercut (40), which under cut provides an abutment stop for a head (42) of a stem (41) carrying the valve member (22), the spring (23) extending between the head (42) and the valve seat (21). The valve member (22)/valve seat (21) may be adjustable on the stem (41). <IMAGE>

Description

SPECIFICATION Water-actuated controller This invention relates to a water-actuated controller for use with a water heater which is operated with gas, oil or electric power, which controller comprises a housing, to which a water inlet line and a water outlet line are connected, one of said lines incorporating a diaphragm-controlled valve and a venturi nozzle, which has an entrance connected to a pressure chamber on one side of the diaphragm and a throat which communicates with a pressure chamber on the other side of the diaphragm, said venturi nozzle being bypassed by a spring-loaded valve, which has a valve member that is controlled by an adjustable stop.

Such an arrangement has already been proposed. The adjustable stop constitutes a water-temperature selector, which acts on the spring which controls the valve member. In that case the temperature-selecting screw can be adjusted to influence the spring force acting on the valve member. As soon as the force which is due to the pressure drop across the venturi nozzle exceeds the pre-adjusted spring force, the valve will open so that the operation of the heater will be initiated by a supply of heating energy. The pressure structure facilitates replacement by a serviceman.

According to the present invention, there is provided a water-actuated controller having the construction set out in the opening paragraph of the present specification, in which the stop limits the maximum opening of the said spring-loaded valve.

In a preferred design, the water-actuated controller has a stepped bore, in which a sleeve is mounted by means of screw threads, said sleeve has female screw threads connected to an adjustable shaft, which is adapted to be rotated by a handle, and said adjustable shafts has a cavity, which is formed with an undercut and accommodates one end of a stem carrying the valve member and also accomodates a spring, which bears on a valve seat element that is movably mounted on the stem. That particularly preferred design affords the advantage that the stepped bore, which in the previously proposed water-actuated controller accommodated a temperature selector which was different in function and design, can now be used for the purposes of the invention without the need for further alterations of the housing of the water-actuated controller.In that case the stop and temperature selector constitute a subassembly which can be installed and removed as such without the risk that parts may be lost. Owing to the undercut the valve seat element and the valve member can easily be caused to snap into the adjustable shaft and the adjustable clearance will be obtained between one end of the adjusting shaft and the other end of the undercut.

An example of a water-actuated controller made in accordance with the present invention is illustrated in the accompanying drawings, in which: Figure 1 is an illustration of the principle underlying the invention, and Figure 2 shows an axial sectional view of the example.

In both figures of the drawing, like reference characters designate like details.

The water heater shown in Fig. 1 is a circulating water heater, in which a primary heat exchanger, not shown, is heated by a gas burner. In dependence on the position of a three-way valve that primary heat exchanger delivers water to a heating circuit, not shown, or through supply lines 2 and 3 to a tap water heat exchanger 1, in which the supply lines 2 and 3 are interconnected by a heat exchanger pipe coil 4.

The heat exchanger 1 might alternatively constitute a primary heat exchanger of a directly acting tap water heater, which is directly heated by a gas burner. Heating may alternatively be effected by an oil burner or by electric resistor coils. In order to turn on the gas or oil burner or the electric power for a directly acting water heater, an actuating screw 5 is provided, which serves to actuate a gas or oil valve or an electric switch. The actuating screw 5 extends through a housing 6 of a water-actuated controller 7. The housing 6 is provided with a tap water inlet 8 and a tap water outlet 9. The tap water inlet 8 is connected to tap water mains. The tap water outlet 9 is connected to a tap line 10, which extends through the heat exchanger 1 and is controlled at its end by one or more tap valves 11.In the housing 6 of the wateractuated controller, a diaphragm 12 is pressure-tightly gripped along its rim 13 to define a first pressure chamber 14 and a second pressure chamber 15, which are separated by the diaphragm. The pressure chamber 15 is pressurized from the inlet 8. A final control element of a water flow rate controller is disposed between the inlet 8 and the pressure chamber 15 and consists of a piston 16, which together with a bore 1 7 defines a constriction. The piston 16 is biased by a compression spring 18, which bears on an extended part of the housing 6 and urges the piston 16 toward the rim of the bore 17. A venturi nozzle 1 9 is connected between the outlet 9 and the pressure chamber 15 and at its throat is connected to a line 20 leading to the pressure chamber 14.The venturi nozzle 19 is by-passed by a valve, which comprises a valve seat 21 and a valve member 22, which is biased by a restoring pressure spring 23, which bears on the housing. The maximum opening of the valve 21/22 is defined by an adjustable stop 24, which is movable by a handle 25 and is so arranged that its end 29 which is remote from the handle 25 faces that end of the valve member 22 which is remote from the valve seat 21.

The diaphragm is provided in the pressure chamber with a diaphragm disc 26, which carries the actuating screw 5, which is biased by a restoring spring 27. The force exerted by the spring 27 exceeds the force exerted by the spring 18 so that in the position of rest, shown in Fig. 1, the constricted flow area between the final control element 16 and the bore 17 is substantially open when the tap valve 11 is closed.

The arrangement shown in Fig. 1 has the following mode of operation.

When the tap valve 11 is opened, water flows from line 8 through the open constriction 16/17 and the pressure chamber 15, the venturi nozzle 19, the line 9, the heat exchanger 1 and the tap line 10. Because the valve 21/22 is closed, water can flow only through the venturi nozzle 19 when the tapping is initiated. As a result, there will be a rapid pressure rise in the pressure chamber 1 5 and a strong pressure drop in the pressure chamber 14 owing to the vacuum produced by the venturi nozzle, which draws water from the pressure chamber 14 through the line 20.

As a result, the diaphragm and the actuating screw 5 are raised against the restoring force of the spring 27. As the actuating screw 5 is raised, the three-way valve is actuated to cause hot water to flow from the primary heat exchanger of the circulating water heater through lines 2 and 3 to the pipe coil 4 so that the tap water flowing there will be heated. In an alternative embodiment, the actuating screw 5 permits gas or oil to flow to a burner for a direct heating of the heat exchanger 1, or the actuating screw actuates a microswitch for initiating the flow of electric current in the heating coils of the heat exchanger 1.

As soon as water at a predetermined rate flows through the venturi nozzle 19, a predetermined pressure drop will result across said nozzle and will influence also the valve member 22 so that the same tends to move in an opening sense against the restoring force of the spring 23. In dependence on the restoring force of that spring the valve member 22 departs from the seat 21 so that water flows along a path which by-passes the venturi nozzle. The flow rate of said water is also automatically controlled by the final control piston 16. The maximum flow rate of the water is determined by the clearance 28 between the end 29 and the valve member 22. When the valve member engages that end, the flow area cannot be increased further.

Because the spring 23 is not influenced by the stop 24, the valve 21/22 will always open in response to the same pressure drop across the venturi nozzle, regardless of the degree to which the tap valve is opened so that the starting characteristics of the heater will not be influenced.

Fig. 2 shows a particular embodiment. The housing 6 of the water-actuated controller is formed with a stepped bore 30, which contains a screwed-in subassembly 31. That subassembly comprises a sleeve 32, which has external screw threads 33, by which the sleeve 32 is screw-connected to internal screw threads in the stepped bore. An 0 ring 34 provides a seal between the stepped bore and the sleeve. The sleeve contains a chamber 36, in which an axially adjustable shaft 37 is mounted by a screw-threaded joint 38. The shaft 37 is rigidly connected to a handle 25 and at that end which is remote from the handle 25 has a cavity 39, which is defined by an undercut 40. That undercut defines the end 29 of the stop 24, which is constituted by the adjustable shaft 37.The valve member 22 is secured to a stem 41, which at that end which is remote from the valve member 22 carries a head 42, which is movably mounted in the cavity 39. The head 42 is so designed that it can be forced into the cavity 39 from the outside to snap behind the undercut 40 so that the head is then captively connected to the adjustable shaft 37. The compression spring 23 bears on the head 42 and at the other end bears on the valve seat, which in this embodiment consists of a valve seat insert. In this manner the compression spring 23 is mounted in part in the adjustable shaft.

The sub assembly 31 has the following mode of operation.

The handle 25 can be rotated to move the adjustable shaft 37 into or out of the housing so that the position of the undercut 40 or of the stop 21 in the housing is changed and the clearance 28 between the head 42 and the undercut 40 is decreased or increased. The spring 23 will not be affected by that adjusting movement because that spring bears only on the valve seat insert 21 and the head 42 and the clearance between said parts cannot be influenced. The spring 23 urges the valve member 22 toward the seat 21. The differential pressure across the venturi nozzle is applied through bores 43 to the interior 44 of the valve seat insert 21 and to that end face of the valve member 22 which faces said insert so that the valve member 22 can lift toward the final control piston 16 so as to stress the restoring spring 23. In position of rest the valve 21/22 will always be closed and the pressure required to open that valve can be adjusted by a rotation of the valve member 21 relative to the rod 41 as these two parts are interconnected by screw threads, which can be blocked by means of adhesive when an adjustment has been effected.

This embodiment affords the special advantage that the entire temperature selector consists of a subassembly, which can be replaced as a whole without a need for other alterations of the water-actuated controller.

Claims

1. A water-actuated controller for use with a water heater which is operated with gas, oil or electric power, which controller comprises a housing, to which a water inlet line and a water outlet line are connected, one of said lines incorporating a diaphragm-controlled valve and a venturi nozzle, which has an entrance connected to a pressure chamber on one side of the diaphragm and a throat which communicates with a pressure chamber on the other side of the diaphragm, said venture nozzle being by-passed by a spring-loaded valve, which has a valve member that is controlled by an adjustable stop, in which the stop limits the maximum opening of the said springloaded valve.

2. A water-actuated controller according to claim 1, in which the end of the stop is disposed at an adjustable distance from that end of the valve member which is remote from the valve seat.

3. A water-actuated controller having a stepped bore, in which a sleeve is mounted by means of screw threads, in which said sleeve has female screw threads connected to an adjustable shaft, which is adapted to be rotated by a handle, and in which said adjustable shaft has a cavity, which is formed with an under cut and accomodates one end of a stem carrying the valve member and also accommodates a spring, which bears on a valve seat element that is movably mounted on the stem.

4. A water-actuated controller substantially as described herein with reference to Figs. 1 and 2 of the accompanying drawings.