GB2186717A - Pressure regulator - Google Patents

Abstract

A pressure regulator which comprises body (1) communicating with inlet, outlet and relief passages (2,3,4) and accommodating membrane 5 which divides body (1) into two spaces (10, 12) relief valve (14) installed between inlet and relief passages (2,4) a regulating valve linked movably with rod (8) which is rigidly linked with membrane (5), and nonreturn valve (35) installed in outlet passage (3). The regulating valve is made in the form of nozzle (15) located in which with a clearance relative to its walls is rod (8), and resilient toroidal flap (16) installed with an interference on circular recess (17) made on the rod and communicating with the atmosphere through the passages of rod (8) in the position shown and sealing the passages in the rod in the open position. <IMAGE>

Description

SPECIFICATION Pressure regulator The present invention relates to the field of automatic regulation and, more particularly, to pressure regulators in pneumatic systems of transport vehicles for maintaining pressure in the air brake systems within preset limits, protecting them against undue pressure rise and pollution, at the same time providing a possibility of bleeding off compressed air, for example for inflation of tyres.

Most successfully the present invention can be used in the pressure regulators ensuring periodic unloading of the compressor and maintaining pressure within the present limits with a certain degree of accuracy, improving their sensitivity and extending their service life.

The essence of the invention lies in that, in the pressure regulator comprising a body communicating with the inlet, outlet and relief passages and incorporating a membrane loaded by a setting spring, said membrane dividing the body into two spaces, viz., an above-membrane space, communicating with the atmosphere and housing the setting spring, and a below-membrane space communicating with the outlet passage which accomodates a rod rigidly connected at one end with the membrane, a piston-type relief valve installed between the inlet and relief passages, a regulating valve connected movably with the rod and putting the head end of the relief valve alternately, in one of the extreme positions of the rod, with atmosphere and, in the other extreme position, with the below-membrane space, and a non-return valve installed in the outlet passage before the point where it communicates with the below-membrane space in the direction of fluid flow, according to the invention, the regulating valve is made in the form of a nozzle located between the below-membrane space and the head end of the piston releif valve and accommodating, with a clearance relative to its walls, the free end of the rod, and a resilient toroidal flap installed with an interference on the circular recess in the rod and communicating, through a radial and an exial channels in the rod with the atmosphere, the flap in one of the extreme positions of the rod bearing against the edge of the nozzle and the face of the recess opposite said edge, communicating the head end of the releif valve with the atmosphere while in the other extreme position of the rod it bears against both faces of the circular recess, putting the head-end space of the relief valve in communication with the below-membrane space.

The regulating valve in the pressure regulator is made, according to the invention, in the form of a nozzle accommodating with a clearance the free end of the rod and a toroidal resilient flap which simplifies the design of both the regulating valve proper and the pressure regulator as a whole.

The location of the free end of the rod in the nozzle with a clearance precludes the effect of the friction forces and axial misalignment of its movement and, as a consequence, on the sensitivity of the pressure regulator and rules out the necessity for providing the seating surfaces and a sealing ring.

The pressure regulator realized according to the present invention is simple to manufacture and reliable.

It is. practicable that the rod should be provided with a flap limit stop in the form of an annular projection arranged between the circular recess and the membrane.

This arrangement ensures limiting the travel of the flap during its interaction with the nozzle, thereby determining its extreme position when the head-end of the relief valve is vented to the atmosphere.

It is desirable that the working space of the flap limit stop be located at a distance smaller than half the diameter of the cross section of the toroidal flap from the nearest edge of the circular recess, which means that the centre of the cross section of the toroidal flap bearing against the limit stop surface should be located at a distance larger than, or equal to, the distance from the stop surface to the face of the recess, nearest to said surface.

This makes it possible to return the toroidal flap into the circular recess from the extreme position in which it bears against the stop. This dispenses with the valve loading spring.

It is expedient that the dimensions of the flap and circular recess be selected by satisfying the relation: D, > 1.5 b1, where: D1-cross section diameter of toroidal flap; b1 width of cylindrical circular recess.

This fixes the toroidal flap in the circular recess and enables it to move to the extreme position wherein said flap contacts the working surface of the stop and the nearest face of the recess, the second face of the recess being out of contact with the toroidal flap.

It is likewise expedient that the dimensions of the nozzle and flap be selected by satisfying the relation: D2 > D3 > D4, where: D2-mean diameter of toroidal flap; D3-nozzle diameter; D4-inside diameter of toroidal flap during interaction of the toroidal flap with the nozzle. This produces the moment of forces which brings the toroidal flap to the extreme position wherein the latter breaks off from the recess face nearest to the nozzle and comes in contact with the working surface of the limit stop.

Meanwhile the free end of the rod is located in the nozzle with a clearance relative to its walls.

To rule out the wear of the toroidal flap in the zone of its contact with the nozzle and to extend its service life, it is good practice to make the nozzle at the side of the below-membrane space in the form of a cylindrical projection merging into a cone at the base, said cone provided with passages for communication between the below-membrane space and the atmosphere.

The passages may be made in the form of radial slots in the cone.

Other advantages of the invention will become apparent from the description of the embodiments of the invention and from the appended drawings in which: Figure 1 illustrates a longitudinal section of the pressure regulator according to the invention with the regulating valve in one of the extreme positions and the relief valve closed; Figure 2-fragment A in Fig. 1, enlarged; Figure 3 is the pressure regulator according to the invention with the regulating valve in one of the extreme positions and the relief valve open; Figure 4-fragment B in Fig. 3, enlarged; Figure 5 shows the regulating valve in one of the extreme positions with the nozzle in the form of a cylindrical projection mating with the cone; Figure 6 is the top view of the nozzle in Fig. 5.

The pressure regulator comprises body 1 (Fig. 1) with inlet 2, outlet 3 and relief 4 passages, said body accommodating an actuator in the form of membrane 5 with lower 6 and upper 7 plates, said membrane being rigidly linked with rod 8 and loaded by setting spring 9. Membrane 5 divides body 1 into below-membrane space 10 communicating with outlet passage 3 through hole 11 and above-membrane space 12 communicating with the atmosphere through hole 13, and accommodating setting spring 9.

Besides, body 1 houses piston-type relief valve 14 between inlet 2 and relief 4 passages while below-membrane space 10 accommodates the regulating valve in the form of nozzle 15 (Fig. 2) and resilient foroidal flap 16 installed with an interference on cylindrical circular recess 17 made on rod 8 which is provided with limit stop 18 interacting with membrane 5. Limit stop 18 has the form of an annular projection on rod 8 between recess 17 and membrane 5.

Cylindrical circular recess 1 7 is vented to the atmosphere through radial 19 and axial 20 passages of rod 8 and through hole 13 in upper cover 21 (Fig. 1) of body 1. Free end 22 (Fig.

2) of rod 8 enters with a clearance into nozzle 15 installed between outlet passage 3 and head end 23 of relief valve 14. Space 23 is formed by body 1 and holiow piston 24 of relief valve 14.

Cylindrical circular recess 17 (Fig. 2) with faces 25 and 26 serves as a seat for resilient toroidal flap 16 on rod 8. Resilient toroidal flap 16 is mounted on rod 8 so that it can interact alternately with edge 27 of nozzle 15, face 25 and working surface 28 of limit stop 18 (as shown in Fig. 2), or with faces 25 and 26 of cylindrical circular recess 17 (as shown in Fig. 4).

The centre of the cross section of resilient toroidal flap 16 when the latter interacts with surface 28 of limit stop 18, face 25, edge 27 of nozzle 1 5 is situated below the level of face 25 of cylindrical circular recess 17 of rod 8.

Face 25 is located at a distance less than half the diameter D, of the cross section of resilient toroidal flap 16 from surface 28 of limit stop 18. This location satisfies the following relations: D, > 1.5 b,, D2 > D3 > D4, where D1-diameter of cross section of resilient toroidal flap 16; b1 width of cylindrical circular recess 17; D2 diameter of centres of cross sections of resilient toroidal flap 16; D3-diameter of nozzle 15; D4-inside diameter of resilient toroidal flap 16 (Fig. 4).

Relief valve 14 (Fig. 3) has the form of damper 29 and seat 30 which is fixed in position by lower cover 31 of body 1. Damper 29 is loaded by spring 32. To clean the compressed air from solid particles, body 1 accommodates a filter (not shown in the Figure).

Stop 33 in lower cover 31 limits the travel of damper 29.

In the initial position membrane 5 is pressed by spring 9 against stop 34 (Fig. 2) while damper 29 of relief valve 14, against seat 30.

Outlet passage 3 houses nonreturn valve 35 which divides inlet 2 and outlet 3 passages.

Valve 35 is installed before (as the fluid flows) the point where passage 3 communicates with below-membrane space 10, i.e. before hole 11.

The pressure regulator is provided with a safety valve and a valve for bleeding off compressed air, for example, to inflate tyres (not shown).

In the embodiment of the regulating valve shown in Figs. 5, 6, the wear in the zone of contact of edge 27 of nozzle 15 with toroidal flap 16, said nozzle 15 is made in the form of a cylindrical projection 36 mating at the base with cone 37 whose passages, i.e. radial slots 38 communicate the below-membrane space with the atmosphere.

The configurations of cylindrical projection 36 and cone 37 are selected so as to satisfy the following conditions: a=2-100.

h=(0.05-0.15) D1, where: a=element angle of cone 37 with the base of cone 37; h-height of cylindrical projection 36 of nozzle 15. The pressure regulator functions as follows.

Compressed air is fed from the compressor to inlet passage 2 (Fig. 1), flows through the inner spaces of body 1 and filter to nonreturn valve 35, forces it off and is further delivered through outlet passage 3 to the pneumatic system.

Part of the air is delivered through hole 11 of body 1 into space 10 under membrane 5.

Damper 29 of relief valve 14 is pressed by spring 32 against seat 30, thus keeping the compressed air entering inlet passage 2 from leaking into the atmosphere. At this moment toroidal flap 16 (Fig. 2) pressed by edge 27 of nozzle 15 comes in contact with surface 28 of limit stop 18 and face 25 of cylindrical recess 17. Head end 23 (Fig. 1) of relief valve 14 is vented to the atmosphere through the clearance between free end 22 (Fig. 2) of rod 8 and the walls of nozzle 15, passages 19 and 20, inside space of upper cover 21 (Fig. 1) and hole 13.

At this moment lower plate 6 of membrane 5 bears against stop 34 of body 1, thereby preventing toroidal flap 16 from being deformed by the force of setting spring 9.

As pressure in the system mounts to the preset level for which setting spring 9 is adjusted, membrane 5 goes up and lifts rod 8 (Figs 3, 4); toroidal flap 16 is relieved from the action of edge 27 of nozzle 15 and, being acted upon by the elasticity forces which tend to return toroidal flap 16 into circular recess 17, comes down on its faces 25 and 26, disconnecting recess 17 from head end 23 of relief valve 14.

Being in contact only with face 25, flap 16 is in an unstable position in which it is in contact over its entire internal surface with face 25 (Figs 2, 4) of cylindrical recess 17 whose diameter is somewhat larger than the inside diameter of flap 16 (installed with an interference) and the centre of cross section of toroidal flap 16 is below the level of face 25 of circular recess 17; in this case the occurring moment sets toroidal flap 16 on two faces 25 and 26 of cylindrical recess when membrane 5 goes upward together with rod 8.

Under these circumstances edge 27 of nozzle 15 cannot act on toroidal flap 16.

Installation of toroidal flap 16 with an interference on cylindrical circular recess 1 7 ensures the requisite pressuretightness in the extreme positions of toroidal flap 16, namely, when it gets in contact either with two faces 25 and 26 of cylindrical circular recess 17 or with face 25 of recess 17 and edge 27 of nozzle 15. The contact of flap 16 with working surface 28 of limit stop 18 permits fixing the position of flap 16 and contributes to the building up of additional elasticity forces in flap 16 proper, said forces moving flap 16 back into contact with two faces 25 and 26 of cylindrical recess 17, thus preventing flap 16 from sticking.

The value of the additional elasticity forces in toroidal flap 16 is governed by the degree of deformation of said flap.

Deformation of flap 16 caused by the force applied by setting spring 9 to membrane 5 is limited by plate 6 coming to bear against stop 34 of body 1 which ensures merely a slight contact between flap 16 and surface 28 of limit stop 18, without further deformation of the flap.

Further lifting of rod 8 (Figs 3, 4) allows the compressed air to flow from below-membrane space 10 through the clearance between toroidal flap 16 and edge 27 of nozzle 15, then through the clearance between free end 22 of rod 8 and the walls of nozzle 15 into head end 23 of relief valve 14.

Under the effect of pressure in space 23, piston 24 starts descending, together with damper 29 of relief valve 14, thus compressing spring 32 of relief valve 14 until said spring comes in contact with stop 33. This opens the hole in seat 30 and the compressed air rushes along the walls of body 1 and lower cover 31 through relief passage 4 into the atmosphere so that air begins to be pumped from the compressor into the atmosphere (Fig. 3).

Pressure in body 1 between inlet passage 2 and nonreturn valve 35 drops and nonreturn valve 35 closes.

As the compressed air is gradually consumed, pressure in the pneumatic system and belowmembrane space 10 decreases.

When pressure drops to the preset level, setting spring 9 expands (Fig. 2), membrane 5 goes down and moves rod 8 also down, denying the access of compressed air from space 10 into space 23 because toroidal flap 16 comes down on edge 27 of nozzle 15 and gets in contact with surface 28 of limit stop 18 and face 25 of cylindrical circular recess 17 of rod 8. Lower plate 6 of membrane 5 comes to bear against stop 34 of body 1. Space 23 of valve 14 is vented to the atmosphere through the clearance between the free end 22 of the rod and the walls of nozzle 15, passages 19 and 20, internal space of upper cover 21 and hole 13. At this instant spring 32 extends and shifts damper 29 and piston 24 of relief valve 14 upward, pressing seat 30 against damper 29. Inlet passage 2 at this stage is disconnected from relief valve 4 and the atmosphere.

The starts the pumping of air into the air brake system and the cycle is repeated over again.

To rule out the wear of toroidal flap 16 in the zone of its contact with edge 27 of nozzle 15 (Fig. 2) and extend its service life, edge 27 of nozzle 15 has the form of cylindrical projection 36 (Figs 5, 6) mating at the base with cone 37 which is provided with radial slots 38.

Toroidal flap 16 of this construction, acted upon by edge 27 of nozzle 15 first interacts with cylindrical projection 36 and is deformed in the zone of contact within the limits of resilience of its material, ensuring pressuretightness in the contact zone. As edge 27 of nozzle 15 continues to act, flap 16 begins to contact the surface of cone 37, thereby preventing further deformation of flap 16 in the zone of contact with edge 27 and its wear in the contact zone.

Hence, the main load applied to toroidal flap 16 for shifting it to the extreme position, wherein flap 16 withdraws from the nearest face 26 of recess 17 and comes to bear against surface 28 of limit stop 18, is taken by the surface of toroidal flap 16 contacting with the surface of cone 37 and, due to a large contact area prevents its deformation and wear. At this stage compressed air is delivered to cylindrical projection 36 of nozzle 15 through radial slots 38.

Claims (8)

1. A pressure regulator comprising a body communicating with inlet, outlet and relief passages, divided by a membrane loaded by a setting spring into two spaces, an above-membrane space communicating with the atmosphere and accommodating the setting spring, and a belowmembrane space communicating with the outlet passage which houses a rod rigidly connected with the membrane; a piston-type relief valve installed between the inlet and relief passages; a non-return valve installed in the outlet passage before (in the direction of fluid flow) the point where this passage communicates with the below-membrane space, and a regulating valve connected movably with the rod and made in the form of a nozzle located between the belowmembrane space and head end of the relief valve; installed in it with a clearance relative to its walls is the free end of the rod and a resilient toroidal flap installed with an interference on a circular recess made on the rod and communicating with the atmosphere through the radial and axial passages of the rod, said flap in one of the extreme positions of the rod bearing against the edge of the nozzle and the counteropposed face of the recess, thus communicating the head end of the relief valve with the atmosphere, while in the other extreme position of the rod said flap bears against both faces of the recess, communicating the head end of the relief valve with the below-membrane space.

2. A pressure regulator as claimed in Claim 1 in which the rod is fitted with a flap limit stop in the form of an annular projection located between the circular recess and the membrane.

3. A pressure regulator as claimed in Claim 2 in which the working surface of the limit stop is located at a distance from the nearest edge of the circular recess, said distance being less than half the diameter of the cross section of the toroidal flap.

4. A pressure regulator as claimed in any one of Claims 1, 2, 3, in which the dimensions of the flap and circular recess are selected so as to satisfy the relation: D11.5b where: D1 cross section diameter of toroidal flap; b-width of cylindrical circular recess.

5. A pressure regulator as claimed in any one of Claims 1, 2, 3, 4 in which the dimensions of the flap and nozzle are selected so as to satisfy the relation: D2 > D3 > D4 where: D2-mean diameter of toroidal flap; D3-nozzle diameter; D4-inside diameter of toroidal flap.

6. A pressure regulator as claimed in Claim 1 in which the nozzle at the side of the belowmembrane space has the form of a cylindrical projection mating with a zone, so that the toroidal flap in the extreme position of the rod interacts simultaneously with the edge of the cylindrical projection and with the surface of the cone which has passages for putting the below-membrane space in communication with the atmosphere.

7. A pressure regulator as claimed in Claim 6 characterized in that the passages have the form of radial slots.

8. A pressure regulator realized mainly as described in the preceding claims with teference to the appended drawings, Figs 1, 2, 3, 4, 5.