Pressure regulator with outlet overpressure security

1. A regulator for compressed gas, said regulator comprising:

a body with a gas inlet, a gas outlet and a gas passage fluidly interconnecting the gas inlet and gas outlet;

a pressure reducer with, in the gas passage, a shut-off device and a movable assembly operatively connected to the shut-off device and delimiting with the body a regulating chamber downstream of the shut-off device;

a pressure relief device in the gas passage downstream of the regulating chamber; and

a flow restriction in the gas passage upstream of the shut-off device, dimensioned for reducing the gas pressure at the gas outlet under a maximum pressure value when the pressure relief device is opened and the shut-off device is opened.

2. The regulator according to claim 1 , wherein the pressure reducer is configured for reducing the pressure at the gas outlet to a reduced pressure value, and the maximum pressure value is equal or less then the reduced pressure value.

3. The regulator according to claim 1 , wherein the pressure relief device comprises a burst disk that bursts and fully opens when the pressure at the gas outlet exceeds a pressure relief value.

4. The regulator according to claim 3 , wherein the pressure reducer is configured for reducing the pressure at the gas outlet to a reduced pressure value, and the maximum pressure value is equal or less then the reduced pressure value; and wherein the pressure relief value is greater than the reduced pressure value and the maximum pressure value.

5. The regulator according to claim 1 , further comprising a non-return valve arranged fluidly downstream of the pressure relief device.

6. The regulator according to claim 1 , wherein the flow restriction is formed by a nozzle mounted on the body in the gas passage.

7. The regulator according to claim 6 , wherein the nozzle is an elongate cylindrical element with, on an upstream side, a calibrated through-hole and, on a downstream side, a larger cavity configured for rotatably engaging with a tightening tool.

8. The regulator according to claim 7 , wherein the body shows a through-hole forming a portion of the gas passage, the nozzle being screwed into the through-hole.

9. The regulator according to claim 8 , wherein the through-hole opens out downstream into a bore housing the shut-off device of the pressure reducer, the shut-off device comprising a closing member comprised of a poppet located in the through-hole and a stem extending from the poppet out of the through-hole into the bore, and a ring-shaped seat mounted adjacent the through-hole and cooperating with the poppet.

10. The regulator according to claim 1 , further comprising a filter element arranged directly upstream of the flow restriction.

11. The regulator according to claim 10 , wherein the filter element is located in a through-hole of the body and retained, on an upstream side, by a shoulder of the through-hole and, on a downstream side, by a nozzle formed by the flow restriction.

12. The regulator according to claim 10 , wherein the filter element is made of a porous rigid material forming a cylindrical wall with an upstream open end and a downstream end closed by a radial wall of the porous rigid material.

13. The regulator according to claim 3 , wherein the burst disk shows a periphery that is pinched between a shoulder formed in the body and a circular front face of a connector that is screwed into the body.

14. The regulator according to claim 13 , wherein a cavity is provided on a downstream side of the burst disk, with a diameter that is at least 40% of a diameter of the burst disk at the periphery thereof.

15. The regulator according to claim 13 , wherein the connector houses a non-return valve arranged fluidly downstream of the pressure relief device.