Dual orifice venturi vacuum drawback assemblies having air breather check valve

1. A dual orifice venturi vacuum drawback assembly for controlling a flow of a fluid from a device, the dual orifice venturi vacuum drawback assembly comprising:

a fluid supply passage that supplies the fluid to the device;

a fluid return passage that returns the fluid from the device;

a shutoff valve positioned on the fluid supply passage;

a bypass passage includes an inlet and an outlet, the inlet connected to the fluid supply passage upstream of the shutoff valve, and the outlet connected to the fluid return passage;

a bypass valve positioned on the bypass passage; and

a dual orifice venturi valve positioned on the bypass passage upstream of the bypass valve, the dual orifice venturi valve includes a venturi inlet, a venturi outlet, a primary orifice, and a secondary orifice, the primary orifice is connected to a primary drawback opening on the fluid return passage by a primary conduit, the secondary orifice is connected to a secondary drawback opening on the fluid return passage by a secondary conduit.

2. The dual orifice venturi vacuum drawback assembly of claim 1 , wherein the dual orifice venturi valve includes a constricted portion at which the primary orifice and the secondary orifice are located, the venturi inlet has an inlet orifice at the constricted portion, the venturi outlet has an outlet orifice at the constricted portion, wherein an area of the outlet orifice is equal to or less than a sum of an area of the primary orifice, an area of the secondary orifice, and an area of the inlet orifice.

3. The dual orifice venturi vacuum drawback assembly of claim 2 , further comprising:

an air breather check valve positioned on the fluid supply passage downstream of the shutoff valve, the air breather check valve is moveable between a normally closed position and an open position, in the normally closed position air is inhibited from flowing through the air breather check valve into the fluid supply passage, and in the open position air is permitted from flowing through the air breather check valve into the fluid supply passage.

4. The dual orifice venturi vacuum drawback assembly of claim 3 , wherein the shutoff valve is switchable between a normally open position and a closed position, in the normally open position fluid is permitted to flow through the shutoff valve to the device, and in the closed position fluid is inhibited from flowing through the shutoff valve,

wherein the bypass valve is movable between a normally closed position and an open position, in the normally closed position fluid flowing from the fluid supply passage is inhibited from flowing through the bypass valve to the fluid return passage, in the open position fluid flowing from the fluid supply passage is permitted to flow through the bypass valve to the fluid return passage.

5. The dual orifice venturi vacuum drawback assembly of claim 4 , wherein upon movement of the shutoff valve from the normally open position to the closed position, and movement of the bypass valve from the normally closed position to the open position, fluid flowing from the fluid supply passage passes through the bypass passage to create a vacuum at the primary orifice of the dual orifice venturi valve that draws fluid remaining in the fluid return passage downstream of the device through the primary drawback opening in the fluid return passage and the primary conduit such that the fluid exits the venturi outlet into the fluid return passage through the outlet of the bypass passage, and fluid flowing from the fluid supply passage passes through the bypass passage to create a vacuum at the secondary orifice of the dual orifice venturi valve that draws fluid remaining in the fluid return passage downstream of the device through the secondary drawback opening in the fluid return passage and the secondary conduit such that the fluid exits the venturi outlet into the fluid return passage through the outlet of the bypass passage.

6. The dual orifice venturi vacuum drawback assembly of claim 5 , wherein upon movement of the shutoff valve from the normally open position to the closed position, fluid is inhibited from flowing through the shutoff valve which moves the air breather check valve from the normally closed position to the open position to permit air from atmosphere to enter the fluid supply passage to facilitate the drawback of fluid in the fluid return passage, the device, and the fluid return passage.

7. The dual orifice venturi vacuum drawback assembly of claim 6 further comprising:

a flowmeter unit configured to control the shutoff valve and the bypass valve, the flowmeter unit is positioned on at least one of the fluid supply passage and the fluid return passage, the flowmeter unit configured to detect a leak in at least one of the fluid supply passage and the fluid return passage,

wherein upon detection of a leak by the flowmeter unit the flowmeter unit controls the shutoff valve from the normally open position to the closed positon to inhibit the flow of fluid to the device and the flowmeter unit controls the bypass valve from the normally closed position to the open position.

8. A dual orifice venturi vacuum drawback assembly for controlling a flow of a fluid from a primary device and a secondary device, the dual orifice venturi vacuum drawback assembly comprising:

a fluid supply passage that connects to a primary fluid supply branch and a secondary fluid supply branch, the primary fluid supply branch supplies fluid from the supply passage to the primary device, the secondary fluid supply branch supplies fluid from the fluid supply passage to the secondary device;

a fluid return passage that connects to a primary fluid return branch and a secondary fluid return branch, the primary fluid return branch returns fluid from the primary device to the fluid return passage, and the secondary fluid return branch returns fluid from the secondary device to the fluid return passage;

a shutoff valve positioned on the fluid supply passage upstream of the primary fluid supply branch and the secondary fluid supply branch;

a bypass passage includes an inlet and an outlet, the inlet connected to the fluid supply passage upstream of the shutoff valve, and the outlet connected to the fluid return passage downstream of the primary fluid return branch and the secondary fluid return branch;

a bypass valve positioned on the bypass passage; and

a dual orifice venturi valve positioned on the bypass passage upstream of the bypass valve, the dual orifice venturi valve includes a venturi inlet, a venturi outlet, a primary orifice, and a secondary orifice, the primary orifice is connected to a primary drawback opening on the primary fluid return branch by a primary conduit, the secondary orifice is connected to a secondary drawback opening on the primary fluid return branch by a secondary conduit.

9. The dual orifice venturi vacuum drawback assembly of claim 8 , wherein the dual orifice venturi valve includes a constricted portion at which the primary orifice and the secondary orifice are located, the venturi inlet has an inlet orifice at the constricted portion, the venturi outlet has an outlet orifice at the constricted portion, wherein an area of the outlet orifice is equal to or less than a sum of an area of the primary orifice, an area of the secondary orifice, and an area of the inlet orifice.

10. The dual orifice venturi vacuum drawback assembly of claim 9 , further comprising:

an air breather check valve positioned on the primary fluid supply branch downstream of the shutoff valve, the air breather check valve is moveable between a normally closed position and an open position, in the normally closed position air is inhibited from flowing through the air breather check valve into the primary fluid supply branch, and in the open position air is permitted from flowing through the air breather check valve into the primary fluid supply branch.

11. The dual orifice venturi vacuum drawback assembly of claim 10 , wherein the shutoff valve is switchable between a normally open position and a closed position, in the normally open position fluid is permitted to flow through the shutoff valve to the primary device through the primary fluid supply branch and to the secondary device through the secondary fluid supply branch, and in the closed position fluid is inhibited from flowing through the shutoff valve,

wherein the bypass valve is movable between a normally closed position and an open position, in the normally closed position fluid flowing from the fluid supply passage is inhibited from flowing through the bypass valve to the fluid return passage, in the open position fluid flowing from the fluid supply passage is permitted to flow through the bypass valve to the fluid return passage.

12. The dual orifice venturi vacuum drawback assembly of claim 11 , wherein upon movement of the shutoff valve from the normally open position to the normally closed position, and movement of the bypass valve from the normally closed position to the open position, fluid flowing from the fluid supply passage passes through the bypass passage to create a vacuum at the primary orifice of the dual orifice venturi valve that draws fluid remaining in the primary fluid return branch downstream of the primary device through the primary drawback opening in the primary fluid return branch and the primary conduit such that the fluid exits the venturi outlet into the fluid return passage through the outlet of the bypass passage, and fluid flowing from the fluid supply passage passes through the bypass passage to create a vacuum at the secondary orifice of the dual orifice venturi valve that draws fluid remaining in the primary fluid return branch downstream of the primary device through the secondary drawback opening in the primary fluid return branch and the secondary conduit such that the fluid exits the venturi outlet into the fluid return passage through the outlet of the bypass passage.

13. The dual orifice venturi vacuum drawback assembly of claim 11 , wherein upon movement of the shutoff valve from the normally open position to the closed position, fluid is inhibited from flowing through the shutoff valve which moves the air breather check valve from the normally closed position to the open position to permit air from atmosphere to enter the primary fluid supply branch to facilitate the drawback of fluid in the primary fluid return branch, the primary device, and the fluid return passage.

14. The dual orifice venturi vacuum drawback assembly of claim 13 further comprising:

a flowmeter unit configured to control the shutoff valve and the bypass valve, the flowmeter unit is positioned on at least one of the fluid supply passage and the fluid return passage downstream of the primary fluid supply branch, the secondary fluid supply branch, the primary fluid return branch, and the secondary fluid return branch, the flowmeter unit configured to detect a leak in at least one of the primary fluid supply branch, the secondary fluid supply branch, the primary fluid return branch, and the secondary fluid return branch,

wherein upon detection of a leak by the flowmeter unit the flowmeter unit controls the shutoff valve from the normally open position to the closed positon inhibit the flow of fluid to the primary device and the flowmeter unit controls the bypass valve from the normally closed position to the open position.

15. The dual orifice venturi vacuum drawback assembly of claim 14 , wherein an air breather check valve is not provided on the secondary fluid supply branch which supplies fluid to the secondary device.

16. A dual orifice venturi vacuum drawback assembly for controlling a flow of a fluid from a primary device and a secondary device, the dual orifice venturi vacuum drawback assembly comprising:

a fluid supply passage that connects to a primary fluid supply branch and a secondary fluid supply branch, the primary fluid supply branch supplies fluid from the fluid supply passage to the fluid to the primary device, the secondary fluid supply branch supplies fluid from the fluid supply passage to the secondary device;

a fluid return passage that connects to a primary fluid return branch and a secondary fluid return branch, the primary fluid return branch returns fluid from the primary device to the fluid return passage, and the secondary fluid return branch returns fluid from the secondary device to the fluid return passage;

a shutoff valve positioned on the fluid supply passage upstream of the primary fluid supply branch and the secondary fluid supply branch;

a bypass passage includes an inlet and an outlet, the inlet connected to the fluid supply passage upstream of the shutoff valve, and the outlet connected to the fluid return passage downstream of the primary fluid return branch and the secondary fluid return branch;

a primary air breather check valve positioned on the primary fluid supply branch downstream of the shutoff valve;

a secondary air breather check valve positioned on the secondary fluid supply branch downstream of the shutoff valve;

a bypass valve positioned on the bypass passage; and

a dual orifice venturi valve positioned on the bypass passage upstream of the bypass valve, the dual orifice venturi valve includes a venturi inlet, a venturi outlet, a primary orifice, and a secondary orifice, the primary orifice is connected to a primary drawback opening on the primary fluid return branch by a primary conduit, the secondary orifice is connected to a secondary drawback opening on the secondary fluid return branch by a secondary conduit.

17. The dual orifice venturi vacuum drawback assembly of claim 16 , wherein the dual orifice venturi valve includes a constricted portion at which the primary orifice and the secondary orifice are located, the venturi inlet has an inlet orifice at the constricted portion, the venturi outlet has an outlet orifice at the constricted portion, wherein an area of the outlet orifice is equal to or less than a sum of an area of the primary orifice, an area of the secondary orifice, and an area of the inlet orifice.

18. The dual orifice venturi vacuum drawback assembly of claim 17 , wherein the primary air breather check valve is moveable between a normally closed position and an open position, in the normally closed position air is inhibited from flowing through the primary air breather check valve into the primary fluid supply branch, and in the open position air is permitted from flowing through the primary air breather check valve into the primary fluid supply branch,

wherein the secondary air breather check valve is moveable between a normally closed position and an open position, in the normally closed position air is inhibited from flowing through the secondary air breather check valve into the secondary fluid supply branch, and in the open position air is permitted from flowing through the secondary air breather check valve into the secondary fluid supply branch.

19. The dual orifice venturi vacuum drawback assembly of claim 18 , wherein the shutoff valve is switchable between a normally open position and a closed position, in the normally open position fluid is permitted to flow through the shutoff valve to the primary device through the primary fluid supply branch and to the secondary device through the secondary fluid supply branch, and in the closed position fluid is inhibited from flowing through the shutoff valve,

wherein the bypass valve is movable between a normally closed position and an open position, in the normally closed position fluid flowing from the fluid supply passage is inhibited from flowing through the bypass valve to the fluid return passage, in the open position fluid flowing from the fluid supply passage is permitted to flow through the bypass valve to the fluid return passage.

20. The dual orifice venturi vacuum drawback assembly of claim 19 , wherein upon movement of the shutoff valve from the normally open position to the closed position, fluid is inhibited from flowing through the shutoff valve which moves the primary air breather check valve from the normally closed position to the open position to permit air from atmosphere to enter the primary fluid supply branch to facilitate the drawback of fluid in the primary fluid return branch, the primary device, and the fluid return passage, and

wherein upon movement of the shutoff valve from the normally open position to the closed position, fluid is inhibited from flowing through the shutoff valve which moves the secondary air breather check valve from the normally closed position to the open position to permit air from atmosphere to enter the secondary fluid supply branch to facilitate the drawback of fluid in the secondary fluid return branch, the primary device, and the fluid return passage.