65. Trashracks. Thirty trashracks are provided for the river outlets intake structure to protect the 66-inch hollow-jet valve from oversize trash. The 30 trashrack sections, each approximately 9 feet wide by 12.5 feet high, as shown on figure 85, were furnished under invitation No. DS-5528.

The trashracks are installed in vertical slots of the river outlets intake structure. The racks consist of 2- by 5/8-inch trash bars supported by 8- by 1-inch horizontal loadcarrying plates which in turn transmit the load to the side members. The 5-3/8-inch clear opening between the trash bars is considered sufficient protection for the hollowjet valves. The trashracks were designed for a differential head of 20 feet at a stress of 33,000 pounds per square inch. The estimated weight of the 30 trashracks is 95,000 pounds.

66. 70-Ton Gantry Crane. One gantry crane is used for both the penstock gates and hoists and the river outlet gates and stoplogs. See section 76 for a complete discussion

of the gantry crane.

OPERATING INSTRUCTIONS

1. (a) To operate hollow-jet valve No I

Open shut-off valves A and B Valves C and D must remain closed

(b) To operate hollow-jet valve No. 2:

Open shut-off valves C and D. Valves A and B must remain closed.

2. Press START push button.

3. (a) To open hollow-jet valve:

Shift four-way valve E to OPEN.

(b) To close hollow-jet valve:

Shift four-way valve E to CLOSE.

4. To stop hollow-jet valve at desired opening:

Shift four-way valve E to NEUTRAL

5. Press STOP push button:

€. Close shut-off valves A and B or C and D. (Valves A, B, C.
and D'must be tightly closed to prevent drift of the
hollow-jet valves).

A. DESIGN:

GENERAL INFORMATION

The hollow-jet valves are designed for 190 psi water pressure.
2. The hollow-jet valves are designed to regulate the discharge of
water from the reservoir outlets.

3. The oil hydraulic system is designed for a maximum operating pres-
sure of 1,000 psi and for a normal operating pressure of 850 psi.
B. OPERATING INFORMATION:

1. A hollow-jet valve is mounted on the discharge end of each of the
two river outlet pipes. A ring-follower gate is installed in each
outlet about 200 feet upstream from the hollow-jet valve.
2. Each ring-follower gate is for:

a. Emergency closure if the hollow-jet valve is inoperable.

b. Shut-off when the hollow-jet valve is not in use.

3. The hollow-jet valve is for:

a Regulation of discharge from the outlet.

b. Shut-off for short periods of time only.

4 The hollow-jet valve will normally be in the closed position when
opening or closing the ring-follower gate. (See Drawing No.
591-0-1087 for operating instructions for the ring-follower gate.)

5. When an outlet is out of service and the ring-follower gate is closed,
the hollow-jet valve should be opened at least 5% to allow the
outlet pipe to drain If the outlet will be out of service for an
extended period, open the hollow-jet volve fully to protect the
plunger from dust and other foreign matter

6. Position indicators for both hollow-jet valves are located in the
control cabinet. The indicator dials are calibrated to show the
valve opening in percentage of total needle travel.

7 For best operation of the hydraulic system the oil temperature
should be 40°F or above; but the system can be operated at
temperatures as low as 0° F

C. BASIC OPERATION:

1. Two headers are provided in the control cabinet. One header is
connected to the closing chambers of the hollow-jet valves thru
shut-off valves A and C. The other header is connected to the
opening chambers of the hollow-jet volves thru shut-off valves
B and D. The four-way volve directs pressure to the proper header
for opening or closing the hollow-jet valves and opens the other
header to tonk in the NEUTRAL position the four-way valve
blocks flow to or from the headers and directs flow from the
pump to the tank.

GENERAL INFORMATION (Continued)

2. Pressing the START push button energizes the magnetic starters,
MSI and MS2, and starts the oil pump motors The circuit is
maintained by auxiliary contacts on the motor starters

3. Pressing the STOP push button de-energizes the starter coils
and stops the pumps When the hollow-jet valve seats in the
closed position, the pressure will rise to 850 psi and open
the pressure switch which in turn opens the holding circuit
to the starter coils.

4. The hollow-jet valves should be operated one at a time
Simultaneous operation of the two valves could produce
an errotic action.

5. For normal operation both oil pumps should run; but if one
pump or motor is inoperable, a single unit can be used to
operate the hollow-jet valves.

D. PRESSURE DEVICE SETTINGS AND FUNCTIONS:
1 Set relief valve, RV-1, at 1.000 psi to limit the maximum system
pressure

2. Set relief valves, RV-2 and RV-3, at 500 psi to limit the pressure
in the opening chombers of the hollow-jet valves.

3. Set the thermal relief valves at 1200 psi to prevent excessive
pressure in the system because of oil expansion with rising
temperature.

4. Set the oil pressure switch to open at 850 psi on rising pressure
and reclose of 650 psi on falling pressure. It functions as the
normal system pressure limiting device and stops the oil pumps
when the hollow-jet valve is closed.

E. OPERATING TIME:

I About 5 minutes are required to close one hollow-jet valve from
the open position. This time will be doubled if only one oil pump
is operating.

2. Opening time is adjustable by means of the flow control valve.
With normal reservoir head on the hollow-jet valve, adjust
the flow control valve so that the hollow-jet will open thru full
travel in about 5 minutes. With no water pressure on the
hollow-jet valve (ring-follower gate closed) the operating
speed will be much slower.

SERVICING

INSTRUCTIONS

A. FILLING SYSTEM WITH OIL:

1 General It is assumed that the hollow-jet valves are in the open
position. Approximately 380 gallons of oil will be required to
fill the system. The oil used should be a clean, light, hydraulic
oil, rust and oxidation inhibited, and having a standard Saybolt
Universal viscosity of 150 seconds at 100°F Special care should
be taken to keep the oil absolutely clean and avoid getting dirt
or any foreign matter into the system during filling Care should
also be taken to be sure all air is vented.

2. Check to be sure the pressure switch is set to open at 850 psi

3 Fill oil tank to the high oil level mark.

a. Check that all drains and air vent valves are closed. Close
shut-off valves A, B, C, and D. Open gage shut-off valve 18C.
Check that four-way valve E is in NEUTRAL position.

b. Tank can be filled in either of the following ways:
(1) Remove filler cap 61B and pour oil directly into tank or
pump oil into tank with a barrel hand pump.

(2) Remove pipe plug 36C from the three-way cock 200 and
attach a temporary suction line from the oil supply. Set
three-way cock for flow from temporary line to pumps.
Press START push button. When oil level reaches high
mark stop pumps and set three-way cock for flow from
tonk to pumps.

SERVICING INSTRUCTIONS (Continued)

4 Fill chambers of hollow-jet valves: (The followings instructions
give the procedure to fill hollow-jet volve No I with valve desig-
nations in parenthesis showing changes in instructions to fill
hollow-jet valve No. 2)

a. Attach hose assembly 12A to drain valves at bottom of hollow-
jet valve No. 1 (hollow-jet valve No. 2), Open drain valves.
Open air vent valves F, H and K (F. G and J) and shut-off
valves A and B (C and D).

b. Press START push button and shift four-way valve E to OPEN
Wait 5 minutes then shift valve E to NEUTRAL

c Close air vent valves F and H (F and G) and downstream drain
valve at bottom of hollow-jet valve. Shift four-way valve E
to CLOSE Check pressure switch setting as valve seats in
closed position Shift four-way volve E to NEUTRAL,

d. Open downstream drain valve at bottom of hollow-jet valve.
Press START push button and shift four-way valve E to CLOSE.
Woit 3 minutes then shift four-way valve E to NEUTRAL.

e Close downstream drain valve, close K (J) and open H (G) Shift
four-way valve E to OPEN and check setting of relief valve
RV-2 (RV-3) [See par 82]. When hollow-jet valve is open,
open drain valve. Wait 2 minutes and press STOP push button.
f. Close air vent volve H (G), Shut-off valves A and B (C and D) and
drain valves at bottom of hollow-jet valve. Remove hose
assembly 12 A

5. Fill oil tank to the high oil level mark.

6. Check setting of relief valve RV-1. [See par 81]

B. TO CHECK VALVE AND SWITCH SETTINGS:

1. To check the setting of relief valve, RV-1, set the pressure switch
to open at 1200 psi, check that valves A, B, C, and D are closed,
start the oil pumps, and shift four-way valve E to OPEN Adjust
the relief valve if necessary so that the pressure gage reads
1,000 psi. Stop the pumps, shift four-way valve E to NEUTRAL.
and reset the pressure switch at 850 psi.

2 Check the settings at relief valves, RV-2 and RV-3. by observing
the pressure gage reading during the opening cycle. The pressure
gage should read 500 psi, if not adjust relief valve.

3 To check the pressure switch setting observe the pressure gage
reading at which the motor stops when the hollow-jet valve seats
in the closed position. Before recalibrating the pressure switch,
check the pressure goge.

4. At two year intervals the pressure gage should be checked against
a calibrated master gage.

C. MAINTENANCE SERVICE:

I The service and maintenance procedures prescribed by the
manufacturer should be followed for the pump, motor, and
other commercial components.

2. Water will accumulate in the bottom of the oil tank and should
be drown off at least once a year thru the drain cock. At the
same time any water accumulation in the hollow-jet valve
chambers should be drown off thru the drain valves. (The
hollow-jet valves should be in the closed position and shut-
off valves B and D open.)

3. The oil filter should be removed and cleaned after the hollow-
jet valves have been in service for one month. Thereafter
· clean at two year intervals.

Figure 84. --Controls for 66-inch hollow-jet valve for river outlets--Operating diagram and instructions. (Sheet 2 of 2.) From drawing No. 591-D-1039.

Figure 85. --Trashrack for the river outlets trashrack structure.