Hydraulic Tools and Equipment

Question 1

Two primary types of Hydraulic Power Units (HPU)…

Answer 1

1) NAVSEA Model-II (MOD II)

2) Portaco ( MK 9 MOD 0)

Question 2

Characteristics of NAVSEA MOD II

Answer 2

1) Skid mounted
2) 2000 psi operating presuure
3) Primary diesel powerd HPU used by NAVSEA
4) 30 gallon hydraulic fluid reservoir.

Question 3

Characteristics of Portaco

Answer 3

1) Man-portable
2) Diesel engine driven
3) 2000 psi max
4) 3.2 gallon hydraulic fluid reservoir.
5) small hydraulic cooling system.

Question 4

Hand pump:

Answer 4

1) used with hydraulic cutter- must use 10,000 psig rated “Synflex” hose.
2) Engine driven units use up to 3,000 psig rated “Synflex” hose.

Question 5

Hydraulic Pump:

Answer 5

1) Provides flow and pressure against resistance.
2) Usually driven by an engine or hand pump.
3) Pressure relief valve (emergency bypass)
4) Hydraulic fluid re-circulation valve (manual bypass).

Question 6

Purpose of pressure relief valve…

Answer 6

1) Prevents damage to the hydraulic system due to over pressurization.
2) Adjustable and preset at 2,000 psig (accept hand pump set at 10,000 psig).

Question 7

Purpose of Hydraulic fluid re-circulation valve…

Answer 7

1) When open, fluid from pump discharges back to reservoir by-passing the tool circuit.
2) With recirculation valve closed, fluid flows through discharge filter and tool circuit.
3) Used to stop fluid flow to tool.

Question 8

Hydraulic Fluid Reservoir:

Answer 8

1) Capacity varies on each unit:
(a) MOD II- 30 gallons.
(b) Portaco- 3.2 gallons.
2) Clear sight tube provides method for checking fluid level.
3) Allows for some cooling of the hydraulic fluid.
4) Allows pressurization and circulation of fluid.
5) Has supply and return lines.

Question 9

Hydraulic Flow Meter:

Answer 9

1) Measures the rate of flow of the hydraulic fluid.
2) Can be internal or external unit.
3) Different tools will require separate flow rates.

Question 10

Hydraulic Temperature Gauge:

Answer 10

1) Monitors temperature of hydraulic fluid
(a) normal fluid temperature range is 80 - 120
(b) never allow fluid to exceed 140 F due to reduction of fluid life.
( c) temperature above 150 F will damage equipment seals.

Question 11

Hydraulic Fluid cooling:

Answer 11

1) Cooling of the fluid can be obtained by placing the excess hose in the water.
2) Portaco has a small hydraulic cooler that is usually sufficient in mild weather.

Question 12

Hydraulic Pressure Gauge:

Answer 12

1) Measures in psig.
2) Normal operation pressure is 2,000
3) Provides means of monitoring the pump pressure output.

Question 13

Hydraulic Flow regulator:

Answer 13

1) Two types:
(a) Manual control assembly
(b) Direct drive:
- Controlled by engine RPM (Throttle)

Question 14

Hydraulic Cut Off Switch

Answer 14

1) Diver operated switch located 6’ to 8’ from the tool.
2) Allows flow to be stopped without waiting for topside.
3) Second diver will maintain the switch while primary diver is operating the tool.

Question 15

Hydraulic Power Unit Before each use:

Answer 15

1) PMS
2) Pre-start Hydraulic Power Unit
3) Check fluid levels, belts, etc.
4) Inspect Hoses.
5) Consult user manual for proper user.

Question 16

When operation HPU ensure…

Answer 16

1) Engine oil pressure above 20 psig.

2) Hydraulic oil level on sight glass stays within proper limits (HPU specific).

Question 17

Hydraulic Hoses:

Answer 17

1) Ensure hoses being set up are of the proper pressure rating. The ratings are printed on the hose.
2) Never substitute a hose assembly rated for a medium-pressure application for a high-pressure application.
3) High pressure “Synflex” thermoplastic Nylon core tube with synthetic fiber or wired braid reinforcement and a polyurethane cover:
(a) rated up to 10,000 psig working pressure for hand pump operated tools.
(b) Rated 2,000 psig for use with hydraulic power tools.
4) Hose connections:
(a) Quick connects.
(b) Male fittings - outlet.
( c) Female fittings - inlet.

Question 18

Clean and preserve tools and equipment with a cleaning lubricating preserving compound with MIL-C-81309 (WD-40, CLP, or equivalent)

Answer 18

.

Question 19

Flow Divider:

Answer 19

1) Used to hook up two tools off one system.

2) Allows quick transition between tools without disconnecting.

Question 20

Tool safety precautions:

Answer 20

1) Positive voice communications shall be established between the diver and topside before operating any power tool underwater.
2) Never exceed the maximum flow rate or working pressure for the tool in use.
3) Keep all loose articles clear of rotary tools to avoid entanglement.
4) use appropriate eye and hearing protection when using tools on the surface.
5) Never operate damaged tools or tools that are missing safety guards.
6) Be prepared for sudden wrenching and jerking in case the tool binds up.

Question 21

Environmental Considerations:

Answer 21

1) The HPU must be set to zero flow rate before lowering tools to diver. HPU flow is verified when pressure reading is indicated as zero on the flow meter.