# US 2015/0087209 A1 · Dual Control Dead Man System

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- Number: US 2015/0087209 A1
- Document ID: US20150087209A1
- Status: Published application
- Kind: A1
- Application number: 14/562,153
- Filed: 2014-12-05
- Published: 2015-03-26
- Earliest claimed: 2012-09-24
- Assignees: Graco Minnesota Inc.
- Inventors: Keith Eliason
- Web page: https://patentgrep.com/patent/US20150087209A1

## CPC

- B24C 9/00: Appurtenances of abrasive blasting machines or devices, e.g. working chambers, arrangements for handling used abrasive material
- F16K 17/36: actuated in consequence of extraneous circumstances, e.g. shock, change of position
- Y10T 137/86574: Supply and exhaust
- Y10T 137/86614: Electric
- B24C: ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
- F16K: VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING {(devices for emptying and evacuating the excess liquid in valves or conduits F16L55/07)}
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A dual control shut off system, such as a dead man system for a blasting system, blasting equipment, or other equipment having both pneumatic and electric safety control circuits, may include an electric dead man's switch or a pneumatic dead man's switch. An embodiment of the dual control dead man system is for wet abrasive blasting systems used for cleaning, preparing surfaces, removing coatings, and/or other abrasive blasting operations. Embodiments of the dual control shut off system provide the ability to conveniently switch between an electric and pneumatic shut off system.

## Claims

### Claim 1

A safety shut-off system capable of being controlled by either an electric dead man's switch or a pneumatic dead man's switch, comprising:
a relay valve, wherein the relay valve capable of switching from a venting position to an operating position, wherein in the operating position the pressurized gas port is in fluid communication with the control circuit inlet/outlet;
a pneumatic dead man's switch capable of being connected to the relay valve and engagement of the pneumatically operated dead man's switch shifts the relay valve from its venting position to its operating position; and
an electrically operated dead man's switch capable of being connected to a solenoid of the relay valve and engagement of the electrically operated dead man's switch shifts the relay valve from its venting position to its operating position.

### Claim 2 (depends on 1)

The safety shut-off system of claim 1, comprising a pressurized gas port, a control circuit inlet/outlet, and a spool chamber vent.

### Claim 3 (depends on 2)

The safety shut-off system of claim 2, wherein the pneumatically operated dead man's switch is connected to a spool chamber vent of the relay valve

### Claim 4 (depends on 1)

The safety shut-off system of claim 1, wherein the relay valve comprises a electrically operated solenoid valve; wherein the solenoid valve in its operating position provides fluid communication between the pressurized gas port and a spool chamber in the relay valve and at the same time blocks the pneumatic dead man's port, and the solenoid valve in its venting position provides fluid communication between the pneumatic dead man's port and the spool chamber.

### Claim 5 (depends on 1)

The safety shut-off system of claim 1, comprising a control circuit and the control circuit is in fluid communication with the control circuit inlet/outlet and the control circuit is in fluid communication with at least one pneumatically operated shut off valve.

### Claim 6 (depends on 1)

The safety shut-off system of claim 1, wherein a control line from the pneumatic dead man's switch is connected to the relay valve.

### Claim 7 (depends on 6)

The safety shut-off system of claim 6, wherein engaging of the pneumatic dead man's switch provides fluid communication between a source of pressurized gas and the relay valve to shift the spool from the venting position to the operating position.

### Claim 8 (depends on 7)

The safety shut-off system of claim 7, wherein the operating position provides fluid communication between a source of pressurized gas and the control circuit.

### Claim 9

A blast system, comprising:
a slurry piping system, wherein the slurry piping system comprises a slurry shut off valve;
a pressurized gas piping system;
a relay valve connected to a source of pressurized gas and a control circuit, wherein the control circuit is connected to slurry shut off valve;
an pneumatic dead man's switch capable of being connected to the relay valve and engagement of the pneumatically operated dead man's switch shifts the relay valve to its operating position; and
an electrically operated dead man's switch capable of being connected to a solenoid of the relay valve and engagement of the electrically operated dead man's switch shifts the relay valve to its operating position.

### Claim 10 (depends on 9)

The blast system of claim 9, wherein the pressurized gas piping system comprises an air shutoff valve and the control circuit is connected to air shutoff valve.

### Claim 11 (depends on 10)

The blast system of claim 10, comprising a mixer, wherein the slurry piping system and the pressurized gas piping system are connected to the mixer.

### Claim 12 (depends on 11)

The blast system of claim 11, wherein an abrasive media piping system comprises a blast hose and a blast nozzle and one of the pneumatically dead man's switch and the electrically operated dead man's switch is connected adjacent to the blast nozzle.