Abstract:
A hydraulic reel is used to organize the streamer harness inside a tank having a nozzle. A piston attached to the harness is inserted into one end of the streamer jacket affixed to the tank nozzle. The tank is filled with a liquiform fluid, hereinafter called oil. Pressure is applied to the tank, the piston is pushed through the jacket, towing the harness. Pressure causes some jacket expansion. Initially, with the jacket in place on the nozzle, a main pump fills the tank rapidly, almost to overflow. A metering pump then fills the tank until oil enters a gage glass, indicating a full tank. A flow meter is set to zero with gage valve closed. Oil is metered into the tank, forcing the harness into the jacket. All oil entering the tank is metered until the end bulkhead is in banding position. The metering pump is reversed to extract excess oil until the required quantity is present in the jacket, as indicated by the net meter reading. The loaded section is exercised to relax the jacket skin, then is banded, trimmed and terminated. 
     Alternatively, when tank is full and oil is visible in gage glass, air is admitted to tank above oil to force oil and harness into jacket, oil is then metered into tank until oil is at some level in gage glass. Then gage valve is closed and requisite oil extracted from jacket by reversing meter pump as in first method.

Description:
BACKGROUND OF THE INVENTION 
     This invention pertains to method and apparatus for the manufacture of hydrophone streamers useful for seismic exploration over water. More particularly the invention relates to method and apparatus for filling such streamers with a predetermined amount of oil to achieve the desired degree of streamer buoyancy, which may be positive, negative, or neutral. 
     A seismic streamer comprises a cable harness inside an oil filled sheath. The sheath is a flexible plastic tube. The harness includes a plurality of hydrophones and associated electrical conductors, strain rope, spacers, and bulkheads. Method and apparatus for the manufacture of a hydrophone streamer are disclosed in U.S. Pat. No. 3,885,286 to A. C. Hill, assigned to the same assignee as the present application, the disclosure of that patent being incorporated herein by reference. 
     According to the disclosure of the Hill patent prior to assembly with the sheath, the harness is wound on a reel inside a pressure vessel containing oil and air. One end of the harness is fed through a spigot at the side of the vessel below the oil level and connected to a free piston which is inserted into one end of the sheath. The sheath is attached to the spigot at the side of the vessel below the oil-air interface. 
     The air in the tank is presurized placing the oil under pressure, and the harness and oil are fed to the sheath through the spigot. The pressurized oil forces the piston to move along the several hundred feet of sheath, pulling the harness into the sheath at a rate regulated by unwinding of the reel. The reel is actuated by a hydraulic motor. 
     The piston is provided with a lubricator at its leading end, a pint or so of oil being placed in the sheath before it is attached to the spigot. The sheath is initially expanded by admitting air under pressure through a check valve at the other at the other end of the sheath from the end attached to the spigot. A pressure relief valve maintains the desired air pressure in the sheath. 
     Since the sheath, or jacket as it is now called, expands during insertion of the harness, the precise internal volume of the jacket is variable. This results in the amount of oil in the streamer being uncertain, even though the jacket is &#34;filled up&#34; with oil in the process of inserting the harness, in order to get the harness all the way into the jacket and in order to eliminate air bubbles from the streamer. 
     It is desirable to end up with only a predetermined amount of oil and no air in the streamer, after the harness has been inserted. That is the objective of the invention. 
     SUMMARY OF THE INVENTION 
     According to the invention, instead of applying air pressure to the pressure vessel, or reel tank as it may be called, in order to force oil from the tank into the streamer jacket, the tank is filled with oil, using a large flow rate pump, while venting air from the top of the tank. The air outlet is then closed and oil injection to the tank continued, employing a small pump and flow meter. This forces oil into the streamer jacket. Or alternatively the air outlet valve is opened and air is injected to force the oil out of the tank into the jacket, and then when the jacket is full, metering oil until the tank is full again. Regardless of the method of injecting the oil, when the jacket is filled it will contain more oil than is desired, e.g. more than required for neutral buoyancy. The metering pump is then reversed to extract the excess oil through a reverse flow meter until the desired quantity of oil is present, as indicated by the net of the flowmeter readings. The jacket is then exercised to relax the jacket skin from the previous expansion. The jacket is then banded, trimmed, and terminated. 
     The total volume oil added to the system during the metering process is the amount necessary to replace the oil pumped into the jacket plus the amount equal to the harness volume, the latter being known, e.g. by immersion in a tank of liquid and measuring the overflow, or other equivalent displacement method. The oil added to the jacket is the difference between the total oil added and the harness volume. 
     It has been found that by using the method of the invention, the oil injected into the streamer jacket may be measured to about 3 percent accuracy. Accurate oil measurement requires total filling of the reel tank to eliminate air pockets. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a detailed description of the invention reference will now be made to the accompanying drawings wherein 
     FIG. 1 is a combined vertical section and schematic view of apparatus according to the invention; 
     FIGS. 2A and 2B, sometimes hereinafter referred to collectively as FIG. 2, together form a schematic view of the hydraulic and pneumatic system of the invention; 
     FIGS. 3A-3F, sometimes hereinafter referred to collectively as FIG. 3, together form a schematic view of the electrical system of the invention 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     Referring now to FIG. 1, apparatus according to the invention includes a pressure vessel or reel tank 11. In the tank is rotatably mounted a reel 13. The reel is driven by hydraulic motor 15. Motor 15 is connected by plural flow passage hydraulic cable 17 to hydraulic power supply and control unit 19. On the reel is wound a hydrophone harness indicated schematically at 21. The harness is connected by eye 23 to tow line 25. The tow line is connected to the end of pilot piston 27. Piston 27 is fed into streamer jacket 29 which is attached at one end to nozzle 31 secured to the reel tank. 
     Oil can be supplied to the tank 11 from reservoir 41, or returned thereto, by pump and metering means 43, through flow line 45 entering near the bottom of the tank through valve 46. Air can be supplied to the tank or allowed to exit therefrom, through flow line 47 connected to the top of the tank. Line 47 connects through &#34;gage&#34; valve 48 to air supply and vent means 49 via air/oil valve and gage means 51. 
     According to the disclosure of the aforementioned Hill patent, oil was introduced into the tank 1 to a level above nozzle 31, e.g. to the level shown in FIG. 1, which is above the harness 21 and reel 13. The air pressure was built up in the top of the tank 11 to force piston 27 along jacket 29, drawing harness 21 into the jacket. According to the present improvement, the tank is initially completely filled with oil, the oil is metered into the tank and thereby forced into the streamer jacket, or air is introduced into the tank forcing the oil into the jacket and then the oil is metered into the tank to fill it. When the harness is in place in the jacket, excess oil is withdrawn in measured amount until the desired amount remains in the jacket. Apparatus for this purpose, indicated only generally in FIG. 1, is detailed in FIG. 2. 
     Both in the method of the Hill patent and in accordance with the present invention the harness is wound on a reel in the tank and then payed out into the streamer jacket. The hydraulic system for that purpose will be described first. 
     Referring now to FIG. 2 there is shown a hydraulic power unit 111, including an electric motor 113 driving a pump 115. The pump takes hydraulic fluid, e.g. a light oil, from low pressure storage tank 117 via flow line 119 and delivers it at a high pressure via line 121. Pressure gage 122 shows the pressure in high pressure line 121. Line 121 leads to 3-way manual reversing valve 123. In the neutral position shown, fluid can flow from line 121 through the valve 123 to return line 125 and filter 127 back to tank 117. 
     If valve 123 is shifted up, fluid flows from line 121 through valve 123 and line 129 to hydraulic powered reel motor 15, causing the motor to revolve in one direction. The fluid returns from the motor via flow line 133 and valve 123 to line 125. If valve 123 is moved down, fluid from line 121 moves through valve 123 into line 133 and thence to reel motor 15, causing the motor to revolve in the opposite direction. The fluid then returns from the motor via flow line 129 and valve 123 to line 125. At all times, excess fluid can drain from the motor 15 via flow line 135 back to line 125 and then to the reservoir tank 117. 
     To supply oil to the tank 11, a reservoir 41 is connected through flow line 151, electric actuated valve 153, and flow line 155 and ballasting manifold 157 to a pair of parallel hydraulic pumps 159. Pump 159 is driven by electric motor 161. From rapid fill pump 159 fluid flows through ballasting manifold 163, flow line 45, and manual valve 46 into the bottom of reel tank 11. With pump 159 actuated, the reel tank can be rapidly filled, e.g. at 100 gallons per minute. A float switch 165 is provided in the reel tank to shut off the rapid fill pump 159 automatically, in the manner hereinafter detailed with reference to FIG. 3. Oil can also be withdrawn from tank 11 by operating the rapid fill pump in reverse. Should the oil pressure in manifold 163 ever become excessive, e.g. due to operating pump 159 to fill tank 11 with valve 46 closed, pressure relief valve 167 will open allowing oil to return to the reservoir through flow lines 169, 171, and 151. 
     Oil can also be supplied to tank 11 from reservoir 41 through line 152, ball check valve 197, flow line 195 and electric actuated two way valve 177, by metering pump 179. Metering pump 179 is driven by variable speed electric motor 181. Pump 179 is connected by flow line 183 to two way differential flow meter means 185 which may comprise forward on fill meter 187 and reverse on drain meter 189. 
     Each meter is a mechanical to electric transducer providing electric output signals. Ball check valves 191, 193 limit flow through each meter to the one proper direction, toward the tank through meter 189, and away from the tank through meter 187. 
     Differential flow meter means 185 is connected by flow line 194 to ballasting manifold 163, so that the metering pump can pump oil to or from tank 11 via line 45 and valve 46. When oil is being withdrawn from tank 11 by the metering pump it flows back to the reservoir via flow line 175 and check valve 173. 
     In accordance with the invention, after a harness has been wound on reel 13, e.g. by feeding it through nozzle 31, and a pilot piston has been attached to the free end of the harness and threaded into the rear end of the streamer jacket, and the near end of the jacket connected to the nozzle 31, the rapid-fill or main pump is actuated to fill the tank to the level of the switch 165, and then the metering pump is actuated to fill the tank full, as indicated by overflow into gage glass 199. Or alternatively the tank could be filled solely with one pump, either the rapid fill pump or the metering pump. Use of the two pumps makes for faster filling initially coupled with better control finally. During such filling oil does not flow into the streamer jacket which is blocked by the piston 27 which is retained by reel 13 and reel motor 15. During such filling air is vented from the tank through &#34;gage&#34; valve 48, thereby insuring that all air is removed from the tank. This also prevents air pressure build up on the tank and avoids needless pressure on the streamer jacket at this time. 
     When oil reaches gage glass 199 it also flows into ballast tank 201 in parallel therewith. Tank 201 may, for example, be a 3 gallon tank. The capacity provided by tank 201 and glass 199 prevents the oil overflowing tank 11 from passing on beyond the gage glass before the operator can turn off the pump. 
     Air leaving tank 11, after passing through gage 199 and liquid valve 203, or through liquid valve 205 and ballast tank 201, leaves via flow line 205 and electric actuated two position air valve 207 to atmospheric vent line 209. 
     If it is desired to use air pressure to force the oil from tank 11 into the streamer jacket, air dump valve 207 can be closed when oil appears in gage glass 199, and air supply valve 211 opened. Compressed air from source 213 then passes through flow line 215, past pressure gage 217, through supply valve 211, adjustable pressure regulating orifice valve 219, and past pressure gage 221 to flow line 223. Any excess pressure, as might occur due to valve 48 being closed, is relieved by pressure relief valve 225 venting to line 209. 
     Air from line 223 flows through the gage means comprising tank 201 and glass 199 and thence through gage valve 48 into tank 11 to force oil into the streamer jacket, the reel 13 being actuated to pay out the harness and pilot piston 27 into the jacket. When the harness is all in place, the jacket being full of oil, the air supply valve is closed, the air dump valve 207 is opened, and the metering pump is operated to refill the tank 11 and bring the oil level back to the original level in the gage glass, the latter being provided with calibrations to facilitate determination of the oil head. 
     If it is desired to meter the oil into the streamer, after the tank is first filled and oil is showing in the gage glass, the gage valve 48 is closed and the metering pump operated to fill the streamer jacket with oil and harness. The situation is then the same as at the end of the air pressure filling method just described. In either case the meter shows the volume of oil pumped into the tank, which is the same as the volume of oil plus harness pumped into the jacket. 
     Next, with the gage valve closed, and after banding the far end of the streamer, the metering pump is reversed to withdraw excess oil in the desired amount as indicated by flow meter means 185. The metering pump is then shut off. The harness is exercised to get the jacket back to its initial unstressed condition and to give the oil an opportunity to flow past all the internal restrictions caused by the harness and to come to equilibrium. The near end of the jacket is then bonded and the streamer jacket is removed from the nozzle 31. The streamer can then be properly terminated at each end. 
     The tank is then emptied of oil preparatory to its next use. The gage valve is opened, the rapid fill pump is reversed, the air dump is closed, and the air supply is opened. With air being pumped in, boiling of the oil due to low pressure in the tank upon rapid oil withdrawal is prevented. If the oil is withdrawn more slowly, e.g. with the metering pump, air dump valve is opened and the air supply valve is closed, air being taken from the atmosphere. 
     Referring now to FIG. 3 there is shown an electric circuit suitable for operating the system, the operation being partially automated and including protective interlocks and various signal lights to indicate the status of the system. The circuit includes a main circuit breaker S-12, closure of which closes main power switch S-11 to energize the system. When manual switch S-10 is closed, starter switch S-2 closes and motor M-1 (113) is started supplying hydraulic power for operating the hydraulic reel motor 15. Operation of the latter is then controlled by manual valve 123 as previously described. 
     To operate the rapid fill pump, mode switch S-1 is moved from off to the rapid flow position. Air valve switch S-9 is moved to the air out position and main or rapid fill valve switch S-8 is moved to the on position and switch S-7 is moved to the fill position, controlling the direction of rotation of motor M-2 (161) and causing tank to fill. Switches S-13 and S-14 are used to position valve V-2 (153). When the tank is nearly full, float switch S-4 (168) opens turning off motor M-2. 
     For metered flow, switches S-7 and S-8 are moved to off position and mode switch S-1 is moved to the metered flow position. Metering pump valve switch S-6 is moved to the on position to open valve V-3 (177) and metering motor controller SCRC is turned to full forward position. This operates motor M-2 to finish filling tank 11. 
     When oil appears in the gage glass 199 controller SCRC is moved to stop oil flow and then the gage valve 48 is closed by closing switch S-5. The flow meter means MR-1, MR-2 (185) is then set to zero and controller SCRC is moved to forward flow, speed being adjusted so that the streamer jacket does not swell too much as the harness is injected. When the harness is all in the jacket, the controller SCRC is moved to the off position. During metering, meter valve V-3 (177) is controlled by switches S-15, S-16. 
     The jacket is banded at the far end, a two or three minute wait allows pressure to stabilize as oil flows past restrictions caused by the harness. Then the controller SCRC is moved to reverse the flow through the metering pump to slowly remove the excess oil. 
     When the meter shows the desired amount of oil has been removed, leaving the correct amount in the jacket, the controller SCRC is moved to stop oil withdrawal. The nozzle end of the jacket is then banded and the gage valve opened. Switch S-9 is moved to the air in position. The meter valve is closed. Mode switch S-1 is moved to the rapid flow position. S-8 is moved to open the main valve and S-7 is moved to the drain position to cause the main pump to move oil from tank 11 to reservoir 41. 
     For air filling, the sequence operation of the same electric circuit would be suitably modified in accordance with the previous description of the method. 
     The following table lists the parts of the apparatus, their location, function, and purpose, after which will be set forth step by step the operating and other procedure and a list of readily replaceable parts. 
     
                                           TABLE 1__________________________________________________________________________SWITCHES, CONTROLS, AND INDICATORS__________________________________________________________________________Item     Location      Function      Remarks__________________________________________________________________________S1  3P3T   Control Panel                Rapid flow on                             Inhibits metered flow                Off          Inhibits all pump control                Metered flow on                             Inhibits rapid flowS2  3PST   Control Box  Hydraulic Pump                             Solenoid controlled by S10S3  3PDT   Control Box  Rapid flow pump fwd                             Solenoid controlled by S7                Rapid flow pump rev                             --S4  SPST   Inside Sheather   Tank         Liquid level limit                             Shuts off rapid flow pump                             when tank is fullS5  SPST   Control Panel                Gauge valve open                             --                Gauge valve closed                             Inhibits rapid flowS6  SPST   Control Panel                Meter valve on                             --                Meter valve off                             Inhibits S5S7  SPDT   Control Panel                Rapid flow pump fwd                             Controls S3                Off                Rapid flow pump revS8  SPST   Control Panel                Main valve on                             --                Main valve off                             Rapid flow pumpS9  SPDT   Control Panel                Air in       --                Air out      --S10 SPST   Control Panel                Hydraulic pump                             Controls S2S11 3PST   Control Box  440VAC on    Solenoid controlled by S12                offS12 DPST   Control Panel                All controls on                             Controls S11                offS13 SPDT   Oil Transfer Box                Control, main valve                             Valve closes automatically                             when metered flow is enabledS14 SPDT   Oil Transfer Box                Status, main valve                             Valve must be open to start                             main pumpS15 SPDT   Oil Transfer Box                Control, metering                             Valve closes automatically                valve        when rapid flow is enabledS16 SPDT   Oil Transfer Box                Status, Metering                             Valve must be open to                valve        start metering pumpS17 SPDT   Gauge Valve Ass&#39;y                Control, Gauge Valve                             Valve can be switched only                             if metered flow is enabledS18 SPDT   Gauge Valve Ass&#39;y                Status, Gauge Valve                             Inhibits rapid flow when                             valve is closedVI      Control Panel                Reel speed and                             Variable flow, reversible,                direction    center open, w/detentV2      Oil Transfer Box                Main oil line valve                             Actuated by dual motorsV3      Oil Transfer Box                Metering line valve                             Actuated by one motorV4      Tank Suction Metering line back-                flow         AutomaticV5      Oil Transfer Box                Return to main                             AutomaticV6      Oil Transfer Box                Metering control                             AutomaticV7      Oil Transfer Box                Metering control                             AutomaticV8      Oil Transfer Box                Safety bypass                             AutomaticV9      Above Sheather Tank                Gauge valve  Actuated by one motorV10     Control Box  Air pressure pump                             Solenoid controlledV11     Control Box  Air input    Solenoid controlledV12     Manometer Tube                Flow control ManualV13     Manometer Tube                Flow control ManualC1      Control Panel                Net oil meter                             Summing counterR1      Control Panel                Air regulator                             Manual control                             Tank pressure regulatorDS1     Control Panel                Air inDS2     Control Panel                Air outDS3     Control Panel                Rapid flow   Control section in useDS4     Control Panel                Metered flow Control section in useDS5     Control Panel                Main valve wait                             Valve in motionDS6     Control Panel                Main valve readyDS7     Control Panel                Sheather tank full                             Main pump stoppedDS8     Control Panel                Meter valve readyDS9     Control Panel                Gauge valve closedDS10    Control Panel                Gauge valve openDS11    Control Panel                Meter valve wait                             Valve in motionDS12    Control Panel                Sheather tank fillingDS13    Control Panel                Sheather tank draining__________________________________________________________________________ 
    
     3. OPERATING PROCEDURE 
     3.1 safety 
     substantial efforts were expended to safeguard operators and to minimize improper system operation. This system is not a toy, however, and requires the full attention of a competent and alert operator. Safety hazards common to all electromechanical systems handling flammable materials are present during cable sheather operations. Attention is called to the following precautions: 
     A. disconnect all power mains before servicing the system. 
     B. be certain that cable jacket is securely clamped to nozzle before pressure is applied. If it blows off or ruptures there will be an immediate 400-gallon oil spill at the nozzle. 
     C. do not exceed rupture pressure of cable jacket. Note that this pressure varies from size to size. 
     D. do not allow smoking or other flame sources in the cable sheathing area or near the oil transfer module. 
     E. keep hands and body clear of nozzle while guiding harness onto reel. 
     3.2 CONTROLS 
     Normal operations are controlled from one panel, shown in FIG. 2. Control and monitor functions are given in Table 1.  The Control Flow Diagram, FIG. 3, shows the function and interaction of controls. Particular attention is called to the notes in FIG. 3 regarding circuit interlocks installed as operational safeguards. These interlocks should never be defeated except by qualified maintenance technicians. 
     3.3 OPERATION 
     Panel control indicator lamps are arranged so that: 
     White indicates normal condition. Operator may proceed to any step as desired. 
     Amber indicates incomplete progress. Operator must wait for white lamp to proceed further. 
     Red indicates a final condition. Operator must remove the red condition before going to any other step. 
     Sections may be loaded by oil pressure only, by air pressure only, or by a combination of the two. 
     3.3.1 Oil Pressure Loading 
     a. Switch OFF all controls at the panel. 
     b. Open all valves between oil supply tank and sheather. 
     c. Close waste oil bypass and any valves where air or other materials can enter the oil system. 
     d. Lay streamer jacket straight ahead of sheather on work table. 
     e. Use tubing expander and heat gun to expand end of jacket. Allow tubing to cool before removing the expander. 
     f. Attach proper adaptor nozzle and corresponding anti-fouling guide at front of sheather. 
     g. Attach drum pull-rope to the streamer harness strain assembly, using care to avoid stressing electrical conductors. 
     h. Switch ON main power. 
     i. Switch air OUT. 
     j. Switch ON hydraulic power. 
     k. Operate reel throttle valve slowly IN. Guide harness carefully into nozzle, maintaining controlled tension to wind firmly on reel. Stop with three feet of harness protruding from the nozzle. 
     Note: pressure relief valve is set to relieve at about 500 PSI to prevent overloading harness. If more torque is required, adjust this valve, (located on the throttle valve) to a higher level. Do not set higher than 2000 PSI. 
     Note: throttle valve has offset center. Push toward panel to actuate IN; pull away from panel to actuate OUT. 
     l. Remove anti-fouling guide and attach the pilot piston (sometimes called MOUSE or PIG). Again exercise caution to ensure that all pulling stress is transmitted through stress members rather than the conductors. 
     m. Pour 1 pint of non-detergent oil or other desired lubricant into the end of the streamer jacket. 
     n. Push guide piston about 12 inches into jacket. Wind remaining harness into drum and clamp some 4 inches of jacket onto nozzle. Leave enough slack in the harness so that the pilot piston won&#39;t accidentally fall into the drum. Place a reference mark on the jacket approximately one foot from nozzle. 
     o. Select RAPID FLOW at selector switch. 
     p. Switch main valve ON. WAIT lamp will indicate until the valve has stopped in open position, at which time the white READY indicator will light. 
     q. Switch main pump to FILL. The tank will begin to fill at about 100 GPM. The float switch will shut off the pump when oil in tank is 4 gallons below overflow. 
     Note: the large oil supply line requires some 50 gallons to fill, so the operator won&#39;t see immediate flow if line is empty. 
     CAUTION 
     The operator should monitor operation at all times, even though the process is automatic. If the jacket clamp slips or if the nozzle becomes disconnected from any cause, oil will spill until the level is below the half-full point. For a full tank, this means 400 gallons. 
     In case of spillage, the operator should immediately switch the main pump to DRAIN. The pump is large enough to hold a vacuum on the nozzle, and can totally prevent spillage. 
     r. Switch main valve OFF when FULL lamp lights to prevent gravity drainage back to supply tank. 
     s. Switch selector to METERED FLOW. 
     t. Switch meter valve ON. Observe WAIT signal and proceed when READY lamp lights. 
     u. Switch SCR controller to FWD. Move speed control clockwise to start metering pump. Flow meter will count up when pump is running forward. Meter approximately 5 gallons of oil into sheather tank, using speed control and REV/FWD switch to set oil level in sight glass to ZERO. 
     v. Switch guage valve to CLOSED, sealing tank full of oil. 
     w. Slowly add oil with metering controls, observing increased tank pressure as indicated by swelling of the jacket at nozzle. Operate reel throttle to OUT, allowing harness to slacken and unwind from drum. As pressure increases, the pilot piston will begin to move through the jacket. 
     x. ZERO flow meter when the end bulkhead passes reference mark (n, above). Some air is usually entrapped during the starting process, and may be worked back into the sheather at this point. 
     y. Meter oil into the tank and simultaneously pay out harness, manually adjusting oil flow rate and reel speed to keep harness from developing excessive slack on the reel, and to limit jacket expansion to about 100 percent. 
     Note: jacket elongation is normal, but can be minimized by loading the harness as rapidly as possible. 
     z. One technician should check the pilot piston&#39;s progress, and should keep the empty jacket straight ahead of the piston. 
     aa. When the trailing end bulkhead reaches the reference mark, band the leading end, trim jacket to length, and return piston to the sheather. 
     bb. The meter reading at this point will equal the volume of the harness assembly plus the volume of oil contained in the jacket. The oil volume will be somewhat greater than desired because the loading operation involves jacket pressurization. 
     cc. Reverse metered flow, slowly removing oil from the jacket until the net meter count reaches the volume previously determined correct for that particular assembly. (Remember that indicated volume includes oil plus harness volume.) Oil removal will apply vacuum to the jacket, causing it to collapse near the nozzle. It is necessary to adjust flow rate to match the rate at which oil can bleed past the end bulkhead, preventing total collapse of the jacket and oil flow stoppage. 
     dd. When meter count reaches the desired volume, allow some two minutes for pressures to equalize, then band the end bulkhead. 
     ee. OPEN guage valve. 
     ff. CLOSE meter valve. 
     gg. Select &#34;RAPID FLOW&#34;. 
     hh. OPEN main valve. 
     ii. Start main pump to DRAIN. As the tank drains, the jacket section at the nozzle will collapse due to vacuum, and eventually the oil will begin to effervesce. 
     jj. Back air regulator to low pressure. 
     kk. Switch air &#34;IN&#34;. 
     ll. Regulate air pressure to prevent jacket collapse, which means air volume in will equal oil volume being removed by the pump. 
     mm. Drain tank until oil level is below the nozzle. 
     nn. Tilt jacket to pour oil back into tank. 
     oo. Cut and trim jacket. 
     pp. Return controls to starting condition. 
     3.3.2 Air Pressure Loading (Oil Filled) 
     This method provides end results similar to those obtained by oil pressure loading (3.3.1 above), and ordinarily would be used only to cross-check results. 
     a. Refer to and follow instructions 3.3.1, a) through u), Page 7. At this point, the harness is ready to load into the jacket, the sheather tank is filled with oil, and the oil level in the sight glass has been set at exactly ZERO. 
     b. Switch SCR control OFF. 
     c. Close meter valve. 
     d. Back air regulator off to ensure low starting pressure. 
     e. Switch air valve IN. 
     f. Adjust regulator to increase pressure until the piston starts to move. Pay out harness as required, keeping slack from forming on reel. 
     Note: air pressure regulation should be balanced to keep the piston moving at a fairly rapid rate, while limiting jacket expansion at the nozzle to less than 100 percent. 
     g. Continue loading under air pressure until the end bulkhead arrives at the reference mark. 
     h. Band and trim leading end of the assembly. 
     i. Open meter valve. 
     j. ZERO net oil meter. 
     k. Use SCR control to meter oil back into the sheather tank, replacing the volume injected into the jacket. Refill tank and adjust level in sight glass to ZERO. The volume shown on the meter at this point will equal harness volume plus the volume of oil in the jacket. The total volume will be greater than desired. 
     l. Close guage valve. 
     m. Operate meter pump in REV mode, very slowly, to extract excess oil from the assembly. Adjust flow rate to prevent total collapse of the jacket at the nozzle. Stop when net oil indication reaches the desired volume. 
     n. Refer to and follow steps dd through pp of Section 3.3.1, pages 10 and 11 above. 
     3.3.3 Air Pressure Loading (Dry) 
     This method is used to load sections free of oil. 
     a. Switch OFF controls at the panel. 
     b. Close oil supply valve at foot of sheather. 
     c. Close waste oil bypass. 
     d. Refer to and follow steps d through n, 3.3.1, page 7. 
     e. Proceed to steps d through h, 3.3.2, page 11. 
     f. When end bulkhead arrives at the reference point, switch air OUT to relieve pressure on tank and jacket. 
     g. Band jacket and proceed to next assembly. 
     4. MAINTENANCE 
     4.1 preventive maintenance 
     the following items should be inspected weekly and corrective measures should be taken as indicated. 
     A. check fluid level in the reel power unit. Refill with good grade hydraulic fluid as required. 
     B. check pressure guage on the hydraulic filter with power unit in operation. Replace filter cartridge when indicated. 
     C. check water level in oil supply tank. Evacuate water as required. 
     
         __________________________________________________________________________ITEM QUAN     PART NUMBER     MANUFACTURER PART NAME   SPECIFICATIONS__________________________________________________________________________P-2  1   37X            Commercial Shearing Co.                                 Pump       100 GPM Rapid TransferP-3  1   PM110PA        BE-GE Mfg. Co.                                 Pump       20 GPM MeteringR-1  1   8804P          REGO Regulators                                 Air RegulatorS-1      82614          Arrow Hart Switches                                 Toggle Switch                                            3PDT Center OffS-2S-11 2   CR206-C102     Gen. Electric Motor StarterS-3  1   8702-SB04      Square D Co.  Contactor  A.C. ReversingS-4  1   L-166-S        Worcestor Controls                                 Switch     Level ControlS-5S-6  2   512TS1-3       Micro Switch  Toggle Switch                                            DPDTS-8S-9  2   512TS1-3       Micro Switch  Toggle Switch                                            DPDTS-7  1   512TS1-1       Micro Switch  Toggle Switch                                            DPDT Center OffS-10 1   511T31-2       Micro Switch  Toggle Switch                                            SPSTS-12 1   190-230-101    Wood Electric Div.,                   Potter &amp; Brumfield                                 Breaker    Main CircuitSCRC-11   63304VE75SR    Boston Gear Ratiotrol                                 Motor      D.C.S.C.R.Speed ControlTB-1thruTB-6 6   8-141          Cinch         Terminal StripsTK-1 1   UNNT9-854296-KS                   BeGe          Reservoir  Hydraulic OilV-1  1   SM1200-OC      BeGe Mfg. Co. Hydraulic Reel                                            For Control ValveV-2  1   2&#34;-444TSE w/B35-5-110/60                   Worcester Miser Valve                                 Valve      Main Rapid Flow Cntl.V-5,6,73   320A1.0-5      Rex Roth Mer. Co.                                 1&#34; Check Valves                                            For Metering LinesV-8  1   11/2&#34; Model T  Lonelgan      Valve      Rapid Flow Relief Set                                            atV-10 1   8210B34        Automatic Switch Co.                                 ASCO 1/2 Valve                                            Normal,Open,Air,OutV-14 1   25B3           Deltrol       Relief Valve                                            3/8&#34; Pressure(Safety)                                            Pillow Block    Type E         Dodge         Bearing    1 15/16&#34; Shaft1   1115-JSC-20    Falk Corp.    Screw Conveyor1   2P1488C        Borg-Warner   Mounting Bracket                                            S.A.E.1   40B 36 Tooth   Dodge         Sprocket1   40B 11 Tooth   Dodge         Sprocket1   40 Pitch       Dodge         Chain    CR123-C8-67A   Gen. Electric Heater Fuses                                            For Motor Starters    312-           Bombo Mfg. Co.                                 Air Cylinder                                            For Jacket Stretcher    No. 346        Parker &#34;O&#34; Ring                                 &#34;O&#34; Ring   For Jacket NozzleDS-1thru 1515  95-0463-09-112 Dialco Indicator Lights                                 Lamp HoldersDS-1thru 1515  B2A            Dialco Indicator Lights                                 Neon Lamps Color ClearDS-1,92   95-0931        Dialco Indicator Lights                                 Lamp Lens  Color RedDS 2,3,4,6,8,1012,13,1415   10  95-0935        Dialco Indicator Lights                                 Lamp Lens  Color WhiteDS-75,11 3   95-0933        Dialco Indicator Lights                                 Lamp Lens  Color AmberC-1  1   G0431-489-1    Hecon Corp.   CounterF-1  1   DP-750-30G                   Line Filter HolderF-1  1   A40147                       Line Filter ElementG-1  1   Type 213-21/2&#34; Wika Pressure Gages                                 Hydraulic Gage                                            0-1500,Flange MountG-3  1   Type 213-21/2&#34; Wika Pressure Gages                                 Tank Pressure Gage                                            0-100,Flange MountG-4  1   Type 213-21/2&#34; Wika Pressure Gages                                 Air Supply Gage                                            0-300,Flange MountM1   1   4543           US Motors     Marine Duty Motor                                            3HP,T.E.F.C.1750 RPMM2   1   3496           US Motors     Marine Duty Motor                                            5HP,T.E.F.C.1750 RPMM3   1   V97500TF       Boston Gear   DC Motor   3/4 HPM4   1   M15-5          Borg Warner   Hydraulic MotorMR-1,MR-2 2   01D15          Niagara-Hersey Prod.Inc.                                 Motor      Liquid FlowMR-1MR-2 2   121AO          Niagara-Hersey Prod.Inc.                                 Transmitter                                            Impulse 120VAC 60 CyP-1  1   S15-5          Borg Warner   Pump       Hydraulic__________________________________________________________________________ 
    
     While preferred embodiments of the invention have been described, many variations will occur to one skilled in the art without departing from the spirit of the invention. For example, throughout the description the material used to fill the streamer jacket has been referred to as oil. However, other liquiform fluids could be used, such as water, or oil with additives.