GB2180918A - Gas tap - Google Patents

Abstract

A plug tap for a gas appliance has an inlet 10 opening radially of the plug (24, Figure 2), a minimum flow passage 14 extending parallel to the inlet and also opening to the plug, and a connection between the parallel passages formed by a portion of a third passage 20 breaking into both passages 10 and 14, and whose axis lies in a plane substantially normal to the axes of the parallel passages 10, 14, passage 20 receiving a screw 22 projectable into the connection to form an adjustable flow restriction. <IMAGE>

Description

SPECIFICATION Gas tap This invention relates to gas taps for domestic appliances such as cookers.

When theflame at a gas burner is turned down by restricting the flow ofgas, there is a minimum flow rate necessary to maintain that flame. Below such rate the flame will fail, although gas continuesto flow. The actual minimum safe rate depends upon the design of burnerforexample.

It is known to provide a gas tap with a flow path via a preset adjustable control, so that the minimum safe flow rate can be provided. Hitherto, so far as we are aware, the actual construction oftap for this purpose has been relatively complex and expensive to manufacture, involving many extra machining operations.

The object ofthe present invention is to provide a particularly simple and hence inexpensive arrangementforthis purpose.

According to the invention a plug tap for a gas appliance has an inlet opening radially of the plug, a minimum flow passage extending parallel to said inlet and also opening to the plug, and a connection between the two parallel passages formed by a portion oaf third passage ofwhich the axis lies in a plane substantially normal to the axes ofthe said parallel passages, the third passage breaking into both of the parallel passages to establish the said connection and being internally screwthreaded over at least a portion of its length to receive and locate a screw, the free end ofthe screw projecting or being projectable intothe said connection to form an adjustableflow restriction.

The tap may have an end cover plate at the larger endofthetapered plug,which may also serve as a niting carrier, held in place by a pair of screws engaged in scerwthreaded bores in the body and the axes ofthe bores being contained in a plane which may also contain the axis of the plug (or being parallel to that axis) and one of these bores may be extended to form said third passage. To prevent gas leakage along the third passage and also to maintain there- stricter screw in an adjusted position therein, the screwthreads may be coated with sealant or an Oring may be employed.

The second passage, that is to say the low flow rate passage extending parallel to the inlet and opening to the plug opens from the body face which is clamped against the gas supply manifold or rail, but is, in use, blanked off at the manifold or rail end by the usual sealing gasket. This avoids any necessity for providing a closure forthe second passage. The third passage is of course closed by the sealing material used around the screw, but possibly additionally or even alternately by the fixing screw for the end plate particularly if a gasket or sealing is used forthat screw.

In manufacture of the tap, the body is required to be held in one position whilst it is being drilled to providethe (main) inlet, and because the second pas- sage is adjacent and parallel, that second passage can be drilled either at the same time, or at least without needing substantial repositioning ofthe body. As mentioned no closure plug is needed, and hence all of the required operations on the bodyfrom that particularfacecan be carried out at one and the same time.

Whenthe body has been repositioned,oralternati velyisbeing machined atthe face at right anglesto that face th rough which the main inlet opens, so asto provide the taper bore forthe plug and to drill and tap the holes for the cover plate, one of the cover plates screw holes is extended and furthertapped to provide the third passage, so that again the operation is a relativelysimple one. The onlyadditional component required when the present invention is used, as compared to a similar tap without any restricter and minimum flow rate provision, is the actual restricter screw itself with its seal or sealing compound.

The plug may be designed with a single radial port which is alternately aligned with the main inlet passage orwith the minimum flow rate passage, orwith neither when the tap is in the off position. If desired separate radial ports may be provided. The tap can be arranged so that it is turned from offtofull on and then to the minimum flow rate orsimmer position, or it may pass from off through the simmer position to the full rate position, as required.

The invention is illustrated in the accompanying drawings in which: Figure l is an elevation of a gas tap according to the invention; and Figure2 is a sectional elevation taken on the line A-A of Figure 1, and showing the tap fixed to a gas rail.

In the drawing, Figure 1 showsthe inlet passage 10 and a pair of screw hoies 12 by means of which the tap can be fixed to a gas rail. The said parallel passage 14 can be seen adjacentthe inlet 10.

Figure 1 is part-sectioned through the axis of one of the screws 16which hold an end cover plate in position, showing the position of the third passage 20 which establishes communication between the pas sages 10 and 14(as better seen in Figure 2.

The screw 22 restricts flowfrom passage 10 into passage 14and hence to the plug, and is presetto a required position.

Figure 2 shows the taper plug 24 with a radial port 26 turned into alignment with the passage 14 and out of alignment with passage 10, that is to say to the low rate position.

1. A plug tap for a gas appliance having an inlet opening radiallyoftheplug,aminimumflowpas- sage extending parallel to said inlet and also opening to the plug, and a connection between the two parallel passages formed buy a portion of a third passage ofwhich the axis lies in a plane substantially normal to the axes of the said parallel passages, the third passage breaking into both ofthe parallel passages to establish the said connection and being internally screwthreaded over at least a portion of its length to receive and locate a screw, the free end of the screw projecting or being projectable into the said connec tion to form an adjustable flow restriction.

2. A plug tap as claimed in Claim 1 wherein the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Gas tap This invention relates to gas taps for domestic appliances such as cookers. When theflame at a gas burner is turned down by restricting the flow ofgas, there is a minimum flow rate necessary to maintain that flame. Below such rate the flame will fail, although gas continuesto flow. The actual minimum safe rate depends upon the design of burnerforexample. It is known to provide a gas tap with a flow path via a preset adjustable control, so that the minimum safe flow rate can be provided. Hitherto, so far as we are aware, the actual construction oftap for this purpose has been relatively complex and expensive to manufacture, involving many extra machining operations. The object ofthe present invention is to provide a particularly simple and hence inexpensive arrangementforthis purpose. According to the invention a plug tap for a gas appliance has an inlet opening radially of the plug, a minimum flow passage extending parallel to said inlet and also opening to the plug, and a connection between the two parallel passages formed by a portion oaf third passage ofwhich the axis lies in a plane substantially normal to the axes ofthe said parallel passages, the third passage breaking into both of the parallel passages to establish the said connection and being internally screwthreaded over at least a portion of its length to receive and locate a screw, the free end ofthe screw projecting or being projectable intothe said connection to form an adjustableflow restriction. The tap may have an end cover plate at the larger endofthetapered plug,which may also serve as a niting carrier, held in place by a pair of screws engaged in scerwthreaded bores in the body and the axes ofthe bores being contained in a plane which may also contain the axis of the plug (or being parallel to that axis) and one of these bores may be extended to form said third passage. To prevent gas leakage along the third passage and also to maintain there- stricter screw in an adjusted position therein, the screwthreads may be coated with sealant or an Oring may be employed. The second passage, that is to say the low flow rate passage extending parallel to the inlet and opening to the plug opens from the body face which is clamped against the gas supply manifold or rail, but is, in use, blanked off at the manifold or rail end by the usual sealing gasket. This avoids any necessity for providing a closure forthe second passage. The third passage is of course closed by the sealing material used around the screw, but possibly additionally or even alternately by the fixing screw for the end plate particularly if a gasket or sealing is used forthat screw. In manufacture of the tap, the body is required to be held in one position whilst it is being drilled to providethe (main) inlet, and because the second pas- sage is adjacent and parallel, that second passage can be drilled either at the same time, or at least without needing substantial repositioning ofthe body. As mentioned no closure plug is needed, and hence all of the required operations on the bodyfrom that particularfacecan be carried out at one and the same time. Whenthe body has been repositioned,oralternati velyisbeing machined atthe face at right anglesto that face th rough which the main inlet opens, so asto provide the taper bore forthe plug and to drill and tap the holes for the cover plate, one of the cover plates screw holes is extended and furthertapped to provide the third passage, so that again the operation is a relativelysimple one. The onlyadditional component required when the present invention is used, as compared to a similar tap without any restricter and minimum flow rate provision, is the actual restricter screw itself with its seal or sealing compound. The plug may be designed with a single radial port which is alternately aligned with the main inlet passage orwith the minimum flow rate passage, orwith neither when the tap is in the off position. If desired separate radial ports may be provided. The tap can be arranged so that it is turned from offtofull on and then to the minimum flow rate orsimmer position, or it may pass from off through the simmer position to the full rate position, as required. The invention is illustrated in the accompanying drawings in which: Figure l is an elevation of a gas tap according to the invention; and Figure2 is a sectional elevation taken on the line A-A of Figure 1, and showing the tap fixed to a gas rail. In the drawing, Figure 1 showsthe inlet passage 10 and a pair of screw hoies 12 by means of which the tap can be fixed to a gas rail. The said parallel passage 14 can be seen adjacentthe inlet 10. Figure 1 is part-sectioned through the axis of one of the screws 16which hold an end cover plate in position, showing the position of the third passage 20 which establishes communication between the pas sages 10 and 14(as better seen in Figure 2. The screw 22 restricts flowfrom passage 10 into passage 14and hence to the plug, and is presetto a required position. Figure 2 shows the taper plug 24 with a radial port 26 turned into alignment with the passage 14 and out of alignment with passage 10, that is to say to the low rate position. CLAIMS

1. A plug tap for a gas appliance having an inlet opening radiallyoftheplug,aminimumflowpas- sage extending parallel to said inlet and also opening to the plug, and a connection between the two parallel passages formed buy a portion of a third passage ofwhich the axis lies in a plane substantially normal to the axes of the said parallel passages, the third passage breaking into both ofthe parallel passages to establish the said connection and being internally screwthreaded over at least a portion of its length to receive and locate a screw, the free end of the screw projecting or being projectable into the said connec tion to form an adjustable flow restriction.

2. A plug tap as claimed in Claim 1 wherein the tap hasan end cover plate at the largerend ofthe tapered plug, which also serves as a niting carrier, held in place by a pair of screws engaged in screwthreaded bores in the body, and the axes of the bores being contained in a plane which also contains the axis ofthe plug or is parallel to that axis, and one of said bores being extended to form said third passage.

3. A plug tap as claimed in Claim 2 wherein the restrictor screwth reads are coated with sealant or an O-ring is provided.

4. Apiug tapfora gas appliance substantially as described with reference to the accompanying drawings.