GB2035516A - Valve for brake retarder of diesel engines - Google Patents

Abstract

This valve may be applied to a Diesel engine in order to intercept the exhaust gases for braking purposes. The valve comprises a body (10) passed through by a duct (11) which widens into a part spherical seat (12), which rotatably accommodates a disc-shaped flap (14). The seat (12) is provided with a circumferential rib (15) which cooperates with a complemental peripheral shoulder of the flap. <IMAGE>

Description

SPECIFICATION Valve for brake retarder of diesel engines It is known that on Diesel engines there may be applied a valve adapted to intercept the exhaust gases in order to enable to utilize the engine as a lost-power pump to brake a vehicle.

The valves for such use raise numerous problems of putting to practice. As a matter of fact they are required to have considerable simplicity of construction so as to be cheap, sturdy, and safe. Moreover, to provide effective braking, they should provide a closure as perfect as possible although considerable thermal stress to which such valves are subjected are to be taken into account.

A kind of valve that results to be suited, by simplicity and quickness of control is the socalled butterfly valve. However, that kind of valve has in its conventional shape as used so far the considerable inconvenience that it has to be made with its flap rotating with ample clearance in its seat. As a matter of fact if the flap were to be made with minimum clearance, as would be desirable for a good tightness of the valve, the valve might be expected to become blocked up if the flap becomes overheated as compared with its seat and, therefore, increased in diameter.

It is an object of the instant invention to provide a butterfly valve for braking retarders that avoids the inconveniences of the state of the art and permits to obtain a satisfactory tightness without any danger of becoming blocked up owing to deformations due to stressing thermal conditions.

For that purpose, according to the invention a butterfly valve comprises a body pierced by a duct that widens into a spherical seat in which a disc-like flap turns about a diametral shaft, at the circumference of the seat there being formed a shoulder having for instance a conical surface, that cooperates with a complemental shoulder formed at the periphery of the flap.

In order to make the objects and features of the valve according to the invention more fully understood, an embodiment thereof is hereinafter described by way of example as illustrated in the accompanying drawing, wherein: Figures 1 and 2 are views in elevation and in plan respectively, of a valve according to the invention; Figure 3 is an enlarged view of a detail of Fig. 2.

The valve comprises a body 10 in which there is provided a through duct 11 that widens into a seat 1 2 having a spherical sector, diametrically in respect of which there is rotatable the shaft 1 3 carrying the stopper 14.

At the inside of the seat 1 2 there is formed a rib 1 5 that provides a lateral face 1 6 e.g. of conical shape, on which there rests the complemental face 1 7 of a peripheral projection 18 of the flap 14.

As can be seen, the projection 1 8 develops in the periphery of the flap over a half circumference at one side and over a half circumference at the other side of the axial plane of the stopper and, therefore the face 1 7 rests respectively at one side and at the other side of the rib 15, to permit rotation of the flap, clockwise in Fig. 2, to open the valve. The rib 15, a projection among various possible ones, may assume an advantageous continuous trapezoidal configuration.

In Fig. 3, where a detail of the zone of contact between the flap and its seat is shown in section, it can best be seen how in the valve it is possible to leave a comparatively great radial clearance indicated by a, that avoids any possibility of blocking-up of the closed flap even if the latter is subjected to strong overheating. For any radial expansion however the tightness is ensured by the contact of the surfaces 1 6-1 7. The configuration of the rib 1 5 is shown to be trapezoidal, but any other functionally equivalent configuration may be adopted as well.

The valve according to the objects of the invention thus results to be correct and reliable, with good sealing when closed, a low resistance to gas flow in open position and non-complicated in manufacture, so that it does not become too costly as compared with conventional valves.

1. A butterfly valve for braking retarder in Diesel engines, comprising a body pierced by a duct widening into a spherical seat on which a disc-shaped flap turns about a diametral shaft, at the circumference of the seat there being formed a shoulder that cooperates with a complemental shoulder formed at the periphery of the flap.

2. A valve according to claim 1, characterised in that the said shoulder in the seat has generically trapezoidal cross-section to provide two conical surfaces, each of which is affected by a substantially semi-circular portion of the complemental shoulder of the flap.

3. A butterfly valve for braking retardation in Diesel engines, substantially as hereinabove described with reference to and as illustrated in the accompanying drawings.

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

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Valve for brake retarder of diesel engines It is known that on Diesel engines there may be applied a valve adapted to intercept the exhaust gases in order to enable to utilize the engine as a lost-power pump to brake a vehicle. The valves for such use raise numerous problems of putting to practice. As a matter of fact they are required to have considerable simplicity of construction so as to be cheap, sturdy, and safe. Moreover, to provide effective braking, they should provide a closure as perfect as possible although considerable thermal stress to which such valves are subjected are to be taken into account. A kind of valve that results to be suited, by simplicity and quickness of control is the socalled butterfly valve. However, that kind of valve has in its conventional shape as used so far the considerable inconvenience that it has to be made with its flap rotating with ample clearance in its seat. As a matter of fact if the flap were to be made with minimum clearance, as would be desirable for a good tightness of the valve, the valve might be expected to become blocked up if the flap becomes overheated as compared with its seat and, therefore, increased in diameter. It is an object of the instant invention to provide a butterfly valve for braking retarders that avoids the inconveniences of the state of the art and permits to obtain a satisfactory tightness without any danger of becoming blocked up owing to deformations due to stressing thermal conditions. For that purpose, according to the invention a butterfly valve comprises a body pierced by a duct that widens into a spherical seat in which a disc-like flap turns about a diametral shaft, at the circumference of the seat there being formed a shoulder having for instance a conical surface, that cooperates with a complemental shoulder formed at the periphery of the flap. In order to make the objects and features of the valve according to the invention more fully understood, an embodiment thereof is hereinafter described by way of example as illustrated in the accompanying drawing, wherein: Figures 1 and 2 are views in elevation and in plan respectively, of a valve according to the invention; Figure 3 is an enlarged view of a detail of Fig. 2. The valve comprises a body 10 in which there is provided a through duct 11 that widens into a seat 1 2 having a spherical sector, diametrically in respect of which there is rotatable the shaft 1 3 carrying the stopper 14. At the inside of the seat 1 2 there is formed a rib 1 5 that provides a lateral face 1 6 e.g. of conical shape, on which there rests the complemental face 1 7 of a peripheral projection 18 of the flap 14. As can be seen, the projection 1 8 develops in the periphery of the flap over a half circumference at one side and over a half circumference at the other side of the axial plane of the stopper and, therefore the face 1 7 rests respectively at one side and at the other side of the rib 15, to permit rotation of the flap, clockwise in Fig. 2, to open the valve. The rib 15, a projection among various possible ones, may assume an advantageous continuous trapezoidal configuration. In Fig. 3, where a detail of the zone of contact between the flap and its seat is shown in section, it can best be seen how in the valve it is possible to leave a comparatively great radial clearance indicated by a, that avoids any possibility of blocking-up of the closed flap even if the latter is subjected to strong overheating. For any radial expansion however the tightness is ensured by the contact of the surfaces 1 6-1 7. The configuration of the rib 1 5 is shown to be trapezoidal, but any other functionally equivalent configuration may be adopted as well. The valve according to the objects of the invention thus results to be correct and reliable, with good sealing when closed, a low resistance to gas flow in open position and non-complicated in manufacture, so that it does not become too costly as compared with conventional valves. CLAIMS

1. A butterfly valve for braking retarder in Diesel engines, comprising a body pierced by a duct widening into a spherical seat on which a disc-shaped flap turns about a diametral shaft, at the circumference of the seat there being formed a shoulder that cooperates with a complemental shoulder formed at the periphery of the flap.

2. A valve according to claim 1, characterised in that the said shoulder in the seat has generically trapezoidal cross-section to provide two conical surfaces, each of which is affected by a substantially semi-circular portion of the complemental shoulder of the flap.

3. A butterfly valve for braking retardation in Diesel engines, substantially as hereinabove described with reference to and as illustrated in the accompanying drawings.