US2795380A

US2795380A - Gas fired water heater

Info

Publication number: US2795380A
Application number: US373647A
Authority: US
Inventors: Donges Hans; Putz Johannes
Original assignee: Joh Vaillant GmbH and Co
Current assignee: Vaillant GmbH
Priority date: 1953-08-11
Filing date: 1953-08-11
Publication date: 1957-06-11
Anticipated expiration: 1974-06-11

Description

June 11, 1957 DNGES Erlu., 2,795,380

GAS FIRED WATER HEATER Filed Aug. 11, 195s z snow-Sheer 1 l 'Inventum Tg M 2 Sheets-Sheet 2 Unvemors JM ff" f W M H. DNGES ETL GAS FIRED WATER HEATER June l1, 1957 Finding. 11, 195s 21,795,380 v Ice VPatented June 1l, 195'? 2,795,380 GAS FIRED WATER HEATER Hans Dnges and Johannes Ptz, Remscheid, Germany,

assignors to `loh. Vaillant K.G., Remscheid, Nordrhein, Westphalia, Germany Application August 11,1953, Serial No. 373,647

6 Claims. (Cl. 236-25) i This invention relates'to a gas heated continuous flow type hot water apparatus with a water deficiency safety device respondingy to the dynamic pressure dilerence.

As is known, such a water deficiency safety device automatically shuts off the gas supply to the burner, as soon as the dynamic pressure difference available at a throttle located in the cold water passage is equalized. This occurs when the hot water tap is closed, i. e. there is no more llow of water. Therefore, considering an inevitable retardation in response, the burner lames will only` extinguish, if there is no more flow of water. The heat stored in the apparatus therefore must be absorbed by the quiescent water, non-admissible heating up of this water occurs thereby which in turn tends to a depositing of boiler scale. This is in particular applicable to hot water apparatus having high flow-out temperatures ranging near the boiling point.

This invention has for its object to dispense with these disadvantageous after-heating phenomena.

According to the invention this object has been accomplished thereby that by the locking motion of the tap valve the dynamic pressure diierence is equalized temporarily at the throttling point, the water deficiency safety device being caused thereby to respond still before the ow of water is interrupted. Thus, the water deficiency safety device is caused to respond prematurely, while water is still flowing through the apparatus, so that after the gas burner has extinguished still a further, possibly even increased flow of lwater takes place which removes the stored heat.

Several possibilities exist to obtain a temporary elimination of the dynamic pressure difference at the water deficiency safety device while the lwater flow is being maintained. This can be accomplished, for instance, thereby that a channel by-passing the throttling point is connected to the depression chamber of the safety device, the by-passing channel being opened temporarily during the locking motion of the tap valve. When opening this bypassing channel, the low pressure is eliminated and may even be converted into overpressure. This result can also be obtained by providing a junction channel between the dynamic pressure chamber of the water deticiency safety device and the flow-out opening of the hot water apparatus. This junction channel is opened temporarily during the closing motion of .the tap valve. The dynamic pressure effective aty the water deficiency safety device is thereby eliminated, so that the water deficiency device cornes to action. Y

To these and other ends the invention consists in the advantageous construction and arrangement which will appear clearly from the following description when read in conjunction with the accompanying drawings wherein two embodiments have been represented as examples.

In the drawings:

Fig. l shows in 'schematical' representation a gas heated cording to the invention,

Fig. 2 is a section through the diaphragm housing of the water deficiency safety device, and

Fig. 3 shows in schematical representation the lower part of a gas heated continuous flow type hot water apparatus of somewhat dierent design.

From the cold water supply designated by the numeral 1, the water enters the pressure chamber 2 and through a flow regulator valve 3 enters the dynamic pressure chamber 4 of a water deficiency safety device which is controlled by a diaphragm 5. The dynamic pressure chamber 4 is connected with a Venturi tube 7 through a joining tube 6. Thus, the water can flow through the Venturi tube 7 yand through a conduit 8 to the heat exchanger 9, and from there through a tapping conduit 10 to a tap valve 11 and to an auxiliary draw oif 12. Due to this ow of water, a dynamic pressure is produced in front of the Venturi -tube 7, i. e., in the dynamic pressure chamber 4. A low pressure is produced simultaneously in the portion of the Venturiftube 7 having the most narrow cross section 7, this narrow portion being termed suction space. A low pressure conduit 14 leads from the suction space of the Venturi tube 7 through a check valve to the low pressure chamber 15 above the diaphragm 5.

A low resistance only is caused by the check valve 13 to v the ilow from the suction space 7' of the Venturi tube 7 to the low pressure chamber 15 of the diaphragm controlled tap mechanism, while a great resistance to fiow is caused by the check valve if the water ows in the oppositek direction.

Pig. 2 shows clearly the structural set up of the valve 13. Thisvalve is composed of a valve disk cooperating with a valve seating. The valve disk is provided with a small opening. A ow of water streaming from .the suction space 7 of the Venturi tubef7 to the low pressure chamber 15 of the diaphragm controlled tap mechanism lifts the valve disk shown at 13, so that there is only a small resistance caused to such a ow by valve 13. But a ow having opposed direction must force slowly through the small opening provided in the valve disk of the valve 13 and therefore has to overcome a greater resistance to How. As longas one of the tap valves 11 or 12 is open and therefore water is allowed to flow through the Venturi tube 7, the -diaphragm 5 is under the inluence of a dynamic pressure difference governing in the chambers 4 and 15. This pressure difference causes the diaphragm to move upwards and'to open a I.gas valve 24 against the action of a valve spring 24. If now the flow of water is throttled and consequently the pressure existing in the suction space 7 rises, a rapid equalization of pressure can then take place via the Valve 13 and through the channel 14. If, however, a negative pressure is produced in the suction space 7 and water is sucked off from the chamber 15 when opening the tap valve 11 or 12, the valve will then perform a braking action causing the diaphragm 5 to lift slowly and the gas Valve to open gradually only. As it is known, such a slow ignition valve has the purpose to avoid a large quantity of gas streaming immediately to the burner and dea'grating when the always somewhat retarded ignition takes place.

The regulator valve 3 fastened to the diaphragm adjusts itself in such a manner that the pressure difference available at the diaphragm 5 is kept constant even if llow of water should vary because of water supply line pressure variations.

A by-passing conduit 16 branches from the pressure chamber 2 and leads through a control valve housing 17 and a branch conduit 16 to the low pressure chamber 15. The conduit 16, 16' by-passes both the Venturi tube 7 and the return valve 13, and as the

conduit

16, 16 branches in front of the regulator valve 3 located in the cold water supply line, a non-throttled stream of water is admitted to the low pressure chamber 15.

A valve body 18 is guided in the `control valve hous ing 17 and is pressed on a valve seat 20 by means of a compression spring 19. The spring 19 is supported by the valve body of the tap valve 11. Another spring V21 tends to press another valve'body` 22l tothe valve seat 2d, however, does not succeedfto close the valves 20/22, since it (Z1) is not able to overcome the stronger spring 19. The valve body 22 rests with its valve spindle 22 in a bored hole 18' of the valve body 18. With the -tap valve 11 fully opened, the valve 22/20 is closed; with the tap valve 11 fully closed, the .valve 18/20 is closed. However, the valve disk 22y is lifted from its seating when the closing movement of the tap valve 11 is almostcomplctcd, while the valve-disk 18 Adoes not yet rest on its seatingv free.

In the represented locking position ofthe tap valve .11'

the by-passing conduit `16, '16 is closed by the valve 18/20, so thatthe water deficiency `safety device is enj` abled to put the apparatus in common manner. to opera.-

tion when drawing off water at the auxiliary tap i2.' As described above, this is effected thereby that the daL phragm 5, under the influence of the dynamic. pressureV gas valve 24 is formed by the hollow cock plug of the A main gas cock and can be hand operated `by means of a With the tap valve 11 opened, the by-passing cont lever.

duit

16, 16 is closed by the control valve 20/'22, as Ynow the spring 21 is enabled to press the valve body 22 on to the seat 20. Thus, the dynamic pressure difference necessary for the above described operation of the apf paratus is also produced at the Venturi tube 7 when the tap valve 11 is open.

If the tap valve 11 is closed,'both valve Abodies 18/22 are lifted by means of the spring 19 during the locking movement. The by-passing conduitvl, 16' is open when the tap valve 11 is in intermediate position, so that the full water pressure available in the chamber 2 `enters the low pressure chamber 15. Consequently the diaphragm 5 is forced downwards whereby on the one hand the gas valve 24 is closed immediately and a larger flow section is made available by the regulatorvalve 3.` When the gas burner 25 is extinguished, an increased flow of Water takes place until the tap valve 11 `is completely closed and the valve body 18 is pressed on-the seat 20. This increased now of water taking place when the` burner is already extinguished eliminates the heat stored in the heating unit 9, so that after-heating of hot water is avoided.

in Fig. 2 the diaphragm housing of the water deficiency safety device has been represented separately. water pressure arises in the low pressure chamber 15, the diaphragm 5 would curve strongly downwards and contact the wall of the lower chamber (dynamic pressure chamber 4) thereby closing more or less the orifice of the supply conduit 6. In order to prevent such a contact of the diaphragm 5 with the wall of the lower chamber, a supporting surface 23 having the shape of a plate is provided in the dynamic pressure chamber -4. The valve body 3 penetrates the plate member 23. The water can therefore ow in undisturbed manner from the regulator valve 3 through the supply conduit 6 tothe Venturi tube 7 even if the diaphragm 5 is curved downwards.

ln the embodiment represented in Fig. 3, cold water enters in the direction of the arrow 25, passes through a throttling point 26, then, as has been signified by the strokedotted line, flows through a heating unit (not represented `in the drawing) and finally appears as hot water in the tap conduit 27. A cold water draw-off valve 28 and a hot water draw-off -valve 29 form a-mixing battery having a dischargeA designatedwbypthe purper-af,

Consequently, the connecting channel 16, 16 'is If the full 30. The diaphragm switch 31 of the water deficiency safety device is connected at both sides'to the throttling point 26 by means of the

channels

32, 33. The diaphragm 31' of the water deficiency safety device 31 is in known manner lifted by means of the dynamic pressure difference arising at the throttling point 26, a not represented burner gas valve being opened thereby by means of a push rod 34. This burner gas valve closes again automatically under the influence of the valve spring when the pressure difference is equalized. A channel 36 connects the dynamic pressure chamber 35 of the diaphragm switch 31 with the draw-off conduit 27, the channel 36 having its end closely arranged above the valve seat of the draw-off valve 29. The mouth of the channel 36 is governed by a tubular valve slide 37 which is fastened by means of bridges 37 to the spindle 38 of the draw-off valve 29. When the draw-otf valve 29 is opened, the valve slide 37 closes the mouth of the channel 36 without thereby hindering the flow-out of hot water from the draw-off conduit 27. Consequently, the pressure difference can be produced which operates the diaphragm switch 31 so as to perform an opening movement of the gas valve.

During the locking motion of the draw-olf valve 29, the valve slide 37 opens the mouth of the channel, thus permitting the dynamic pressure of the chamber 35 to equalize through the channel 36. Therefore, the pressure difference effective at the diaphragm switch 31 is already eliminated before the Waterflow is interrupted by the owoff valve 29. The gas burner therefore already -extinguishes during the beginningtof the locking motion of the flow-off valve. 29, so that Water still flows through the apparatus when the burner is-extinguished and absorbs the stored heat of the heating unit. The flow of water comes to an end only when the draw-olf valve,.29 has reached its seat.

What we claim is:

1. Gas water heater of continuous ow type comprising in combination: a heating unit having a ow system, a gas burner for heatingthe heating unit, a spring-weighed gas valve controlling the gas supply to the burner, a drawoff valve for closing theiiow system, a throttle body being built in the flow system and dividing said system into a dynamic pressure area and a low pressure area, a housing, a motion member dividing said housing into two chambers, said motion member acting upon the gas valve, by means of junction channels, one of said chambers being connected to said dynamic pressure area and the other of said chambers being connected to said low pressure area of the flow system, a valve locked by-pass channel connecting the dynamic pressure area and the low pressure area of theowsystem with each other by-passing thc throttle body, and means adapted to open the valve being located in the by-pass channel while being dependent on the closing motion of said draw-off valve.

2. Gas water heater of continuous ow type comprising in combination: a heating unit having a iiow system, a gas burner for heatingthe heating unit, a spring-weighed gas valve controlling the gas supply to the burner, a drawot valve for closing the flow system, a throttle body being built in the flow system and dividing said system into a dynamic pressure area, and a low pressure area, a housing, a motion member dividing said housing into two chambers, said motion member acting upon the gas valve, by means of junction channels, one of said chambers being connected to said dynamic pressure area and the other of said chambers being connected to said low pressure area of the flow system', a check valve with one by-pass being interposed as slow-acting ignition valve in one of said connection channels, a valve locked by-pass channel connecting thedynamic .pressure area and the low pressure area of the flow system with each other by-passing the throttle pointl and said return valve, and means adapted to open theV valve being located in the by-pass channelwhile being dependent on the locking motion of ,said draw-off valve.

3. Gas water heater of continuous flow type comprising in combination: a heating unit having a ow system, a gas burner for heating the heating unit, a spring-weighed gas valve controlling the gas supply to the burner, a drawoi valve for closing the flow system, a throttle body being built in the flow system and dividing said system into a dynamic pressure area, and a low pressure area, a housing, a motion member dividing said housing into two chambers, said motion member acting upon the gas valve, by means of junction channels, one of said chambers being connected to said dynamic pressure area and the other of said chambers being connected to sai-d low pressure area of the tlow system, a regulator valve being located in the junction channel leading to the chamber of dynamic pressure, said regulator valve being controlled by said motion member, a check valve with one by-pass interposed in the junction channel leading to the low pressure chamber, a bypass channel which on the one side, when viewed in the direction of flow, is connected to the ilow system in front of said regulator valve and by-passing the throttle body and the return valve is led to the low pressure chamber, a closing valve being in said by-pass channel, and means adapted to open said closing valve while being dependent on the locking motion of said ow-off valve.

4. Gas water heater of the continuous flow type according to claim 3, said closing valve being designed as double seat valve and being connected with the flow-oi vaive in this manner that the double seat valve as well with closed as with opened dow-olf valve remains closed and only is opened during closing motion of the ow-off valve.

5. Gas water heater of the continuous flow type comprising in combination: a heating unit having a ilow system, a gas burner for heating of the heating unit, a springweighed gas valve controlling the gas supply to the burner, a draw-orf valve for closing the ow system, a throttle body being built in the ow system and dividing said system into a. dynamic pressure area and a W pressure area, a housing being provided with connecting orifices, a diaphragm being connected with the gas valve and dividing said housing into two chambers, by means of junction channels running into the connecting orifices one of the chambers being connected to the low pressure area, the other chamber being connected to the dynamic pressure area, a supporting member for the diaphragm being arranged inthe chamber of dynamic pressure with distance from the walling of the housing which has been provided with connecting orices, a regulator valve being controlled by said diaphragm, said regulator valve penetrating said supporting member and cooperating with one of said connecting orifices, a by-pass channel being connected, when viewed in the direction of flow, on its one side in front of said regulator valve to the ow system, and by-passing the throttle body is led to the low pressure chamber, a closing valve being provided in said by-pass channel, and means adapted for opening of said closing valve while being dependent on the closing motion of said dow-off valve.

6. Gas water heater of continuous ow type comprising in combination: a heating unit having a ow system, a gas burner for heating the heating unit, a spring-weighed gas valve controlling the gas supply to the burner, a drawoff valve for closing the flow system, a throttle body being built in the ow system and dividing said system into a dynamic pressure area and a low pressure area, a housing, a motion member dividing said housing into two chambers, said motion member acting upon the gas valve, by means of junction channels, one of said chambers being connected to said dynamic pressure area and the other of said chambers being connected to said low pressure area of the iiow system, a valve locked by-pass channel being led from the chamber of dynamic pressure closely to the connecting point of the draw-off valve, said draw-ott valve being arranged at the discharge end of the flow system, and means adapted to open the valve in the by-pass channel while being dependent on the closing motion of the draw-olf valve.

References Cited in the le of this patent UNITED STATES PATENTS