Non-return valve

The present invention relates to a non-return valve (10) used in a preheating chamber (12) of a gas-fueled internal combustion engine having a body (30) including an inlet (32) and an outlet (34) with an intermediate they are traveling on route (38). The outlet passage (34) includes a ball valve (36) which may move between a first position closing the outlet passage (34) and a second position opening the outlet passage (34) for the flow of liquid material, and the valve (36) moves to its first position when the fluid is pressurized in the outlet passage (34) relative to the inlet passage. On the outlet side of the intermediate passage (38) there is an annular valve seat on which the ball of the valve (36) rests in the first position. The outlet passage (34) includes a stop member (42) having a plurality of openings in the outlet passage (34) for providing gas flow. The sealing element (42) screwed into the valve body (30) has a dual function: on the one hand, it holds the ball of the valve (36) in the outlet passage (34) and on the other hand dampens the return of high temperature gases into the outlet passage (34). The inner diameter of the intermediate passage (38) is selected such that a certain amount of gas fuel is flown through the non-return valve (10) in the preheater chamber (12) to achieve the desired gas-air mixture ratio.

First Figure 7424 Ι9Γ

Representative:

Gödölle, Kékes, Mészáros & Szabó Patent and Trademark Office Budapest

Ιίψΐκ

PUBLICATION LITERATURE

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Check valve

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A. (AU)

TRANSGOM GAS TECHNQLOCIES PPÉrLTDTTHer Inventor: NEUMANN Barry Richard,

Date of filing: 1993.1

2:12:14. PL 6347

AU

International Application Number: PCT / AU93 / 00651 Publication Number: WO 94/13986 ^

BACKGROUND OF THE INVENTION The present invention relates to a non-return valve for controlling the unidirectional flow of liquid material, and in particular, but not limited to, a non-return valve used in a pre-combustion chamber of a gas internal combustion engine.

As used herein, the term liquid material refers to any fluid medium, including liquid or gas, even though the embodiment described relates primarily to gas flow.

-2A PCT / AU92 / 00575; International Patent Application No. 5,198,125 discloses a gas delivery system for supplying gaseous fuel to a spark ignition engine. The gaseous fuel is introduced into the vicinity of the spark site, which has a preheat chamber and a combustion chamber which are in communication with one another. The combustion of gaseous fuel begins in the pre-combustion chamber and the combustion effect of the gaseous fuel is directed to the combustion of other gaseous fuels in the combustion chamber. The proportion of gaseous fuel injected into the preheat chamber and combustion chamber is precisely controlled to achieve a minimum fuel / air ratio or low blend combustion.

The non-return valve of the present invention has been developed to provide the delivery of gas to the preheater space or to control the unidirectional flow of a liquid material in other applications.

The invention thus relates to a non-return valve for controlling the unidirectional flow of liquid material through the valve and to prevent the flow of liquid material having a body having an inlet and an outlet, the inlet and the outlet. communicating with one another through an intermediate passage of smaller diameter and a valve seat on the outlet side of the intermediate passage;

a movable valve between a first position on the valve seat that closes the outlet passage and a second position remote from the seat and opening the outlet passage for the flow of liquid material, and the valve it moves to its first position when it is pressurized in the outlet passage as compared to the inlet passage. The inlet passage and the outlet passage are interconnected via an intermediate passage formed by a smaller diameter neck portion, and the valve seat is formed on the outlet side of the neck portion. The valve seat is preferably made of a hard material for wear resistance, thus extending the life of the valve. The valve seat may also be removable so that it can be removed in case of wear or damage.

Preferably, the valve is a substantially spherical element of hard material. In a preferred embodiment, the valve is made of ceramic material. The valve is typically located in the outlet passage.

The outlet passageway has a sealing member having a plurality of openings which allow the flow of liquid material through the outlet passageway. The sealing element has a dual function: on the one hand, it holds the valve in the outlet passage and, on the other hand, dampens the return of the high temperature liquid material to the outlet passage.

The present invention will now be described in more detail with reference to the preferred non-return valve shown in the accompanying drawings, wherein:

First Fig. 3A is a partial sectional view of a preheater chamber in which a non-return valve of the present invention is used; the

Second Figure 1 is a sectional view of the body of the non-return valve of Figure 1; the

Figures 3a, 3b are side and front views of the shut-off member used in the non-return valve of Figures 1 and 2.

Figure 1 illustrates a preferred embodiment of the non-return valve 10 of the present invention as used in the preheating chamber 12 of a gas-fueled internal combustion engine. The preheating chamber 12 is substantially cylindrical and has an upper body portion 14 welded to a lower body portion 16, the base 18 of the upper body portion 14 forming the preheating chamber 20 together with the lower body portion 16. An ignition source formed by a spark plug 22 is screwed into the base 18 of the upper body portion 14 adjacent to the non-return valve 10. To the non-return valve 10 from a gas reservoir, usually a compressed natural gas reservoir (not shown), through a gas line 24

A gaseous fuel is fed through an electromagnetic gas injector.

The non-return valve 10 has a body 30 in which an inlet passage 32 and an outlet passage 34 are formed, the outlet passage 34 communicating with the inlet passage 32. A valve 36 is disposed within the outlet passage 34, which is between a first position closing the outlet passage and a second position opening the outlet passage 34 and allowing the flow of liquid through the check valve 10 (as shown in Figure 1). can move.

As shown in Figure 2, the inlet 32 ​​and the outlet 34 are connected to one another via a neck portion 30 of the body 30, which forms an intermediate passage 38 having a smaller diameter. In this embodiment, the valve 36 is essentially a spherical member or a ball disposed within the outlet passage 34. The neck 30 of the body 30 has an annular valve seat 40 formed on the outlet side of the intermediate passage 38, on which the ball of the valve 36 sits in its first position, in which it closes the outlet passage 34.

In this embodiment, the passageway 38 has an inside diameter of 0.9 mm and is selected to allow a specified amount of gaseous fuel to flow through the non-return valve 10 to achieve the desired gas / air ratio in the preheating chamber 12. . The gas transported from the engine gas injectors is distributed at the inlet port of the corresponding cylinder of the engine such that a large portion is entrained in the combustion space (not shown) while the remainder of the gaseous fuel enters the preheat zone 20 and the non-return valve 10. The relative size of the intermediate passage 38 in the non-return valve 10 and the limiting effect of the gas line leading to the engine cylinder inlet determine the amount of gas entering the preheat chamber and the combustion chamber. Therefore, it is very important to design the non-return valve 10 so that the flow rates do not restrict the flow rate determined by the intermediate passage 38.

-5 In this embodiment, the outlet 34 of the non-return valve 10 is provided with a stop member 42 having one or more openings 44, as shown in Figure 3, so that the gas 34 is discharged through these openings 44. flow through a flight. The sealing member 42 is substantially cylindrical and has an outer thread 46 which fits into an internal thread 48 on the outlet side of the body 30. During use, the sealing element 42, screwed into the body 30, serves a dual function: on the one hand, it holds the ball of valve 36 inside the outlet passage 34 and, on the other hand, prevents unwanted return fluid to the outlet passage 34. In order to avoid entrapment, the thread of the sealing member 42 may be coated with copper or other suitable material. The closure member 42 is generally removable and provided with a diameter groove 50 which allows a conventional screwdriver to tighten or loosen the closure member 42 within the body 30 so that the closure member 42 is easily removed for maintenance, e.g. for cleaning the engine, cleaning the intermediate passage 38, cleaning the outlet passage 34, and / or replacing or repairing the ball of the valve 36.

As mentioned above, all flow areas within the non-return valve 10 are carefully sized to maintain a certain amount of flow through the intermediate passage 38. so e.g. the space between the ball of valve 36 and valve seat 40 in the open position of the ball is dimensioned to be the same as the cross-sectional area of ​​intermediate passage 38. Since there is a sound velocity flow at this location, the flow pressure is 0.544 times the inlet pressure, which increases the specific volume of the gaseous fuel approximately inversely (1.84). Therefore, the annular space between the valve ball 36 and the outlet passage 34 is sized to double the flow space between the valve ball 36 and the valve seat 40. The same consideration applies to the stop member 42, which has a flow space of four times the flow space between the valve ball 36 and the valve seat 40. This is achieved by making holes 4 x 0.9 mm in diameter in the sealing member 42.

-6When ignited, hot gases enter the non-return valve 10 from the preheating chamber 20. In order to protect the valve ball 36 and valve seat 40 from overheating, the 4 x 0.9 mm holes in the sealing member 42 are designed to attenuate the gases. The same gases force the valve ball 36 into the valve seat 40 to block the outlet passage, thereby preventing these gases from returning to the gas conduit 24 via the intermediate passage 38.

The dimensions of the outlet passage 34 and the ball of valve 36 are such that the ball of valve 36 is securely sealed against the valve seat 40 when explosive gases return through holes 44 of sealing member 42. In the event that these dimensions are not sized properly, the gases will surround the ball of valve 36, preferably without being pressed against the valve seat 40.

Preferably, the ball of valve 36 is made of a hardened material in order to extend the life of the valve, since the ball of valve 36 repeatedly strikes the valve seat 40 and the sealing member 42. Likewise, the valve seat 40 is preferably made of a hardened material, e.g. hardened steel from which the valve body 30 is made. Alternatively, the valve seat itself may be a hardened, replaceable material. It may be disadvantageous to harden the entire body 30 as it will then be too brittle and may easily break when the check valve 10 is removed from the preheat chamber 12 for maintenance. Preferably, the ball of valve 36 is of a material other than that of the valve seat 40, e.g. ceramic material to prevent corrosion and / or local welding between valve ball 36 and valve seat 40. In the illustrated embodiment, the valve seat 40 has a truncated cone surface with a bending angle of 59 ° to the central axis 52 of the valve body 30.

The valve body 30 is substantially cylindrical in shape and has a hexagonal head 54 on the outside at the inlet side so that the valve can be clamped in or out of a conventional socket. On the input side, the body 30 also has a tight one

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tolerance parallel internal thread 56 for connecting the gas pipe to the non-return valve using a suitable sealing device.

On the outlet side, the valve body 30 has a tapered outer thread 58 formed in a manner corresponding to a thread in the base 18 of the upper body portion 14 of the preheating chamber 12. Using a taper thread (1/8 inch BSPT) on the body 30 of the non-return valve will provide good seal and good heat transfer between body 30 and preheat chamber 12. To avoid pinching, thread 58 of body 30 may be coated with copper or other suitable material. In addition, the clamping of the tapered outer thread 58 with a radially inwardly closing force secures the closure member 42 in the body 30 and prevents it from loosening during use.

The non-return valve 10 of the preferred embodiment is described in detail above. It will be apparent to those skilled in the art that many changes and modifications can be made to the embodiment described without departing from the spirit of the invention. For example, the valve 36 does not have to be ball-shaped, for example it may be cylindrical, in which case the valve seat must be modified accordingly. In addition, the relative diameters of the inlet, intermediate, and outlet passages relative to one another may be significantly different from those shown when the flow rate of liquid through the valve is less critical. Alternatively, other ways of keeping the valve in the outlet passage may be employed, but are particularly advantageous because of the dual function of the preferred embodiment shown. All such changes and modifications are within the scope of the invention as defined in the foregoing description and the appended claims.