I: Geometrical moment of inertia (cm4) I: Distance between supports of a spindle (cm)

This article is applicable to a gate hoist, a machine bed, and sheave and sheave-fixed parts on the leaf. When the maximum torque of a motor acts on a hoisting deck and a hoisting frame, its stress should not exceed 90% of the yield, stress.

The allowable bearing pressure of a bearing should be decided depen­dent upon load, circumferential speed, PV value (maximum allowable coefficient of velocity) and oil conditions. An example, for reference pur­poses, is given in Table 2.25-2.

Table 2.25-2 Allowable Bearing Pressure

Allowable bearing pressure (kgf/cm²)

Type	Hinged pan		Fixed part
	Hoist	Support
Bronze castings (BC) Phosphor bronze castings (PBC)	[70 - 100	150 - 200
Leaded tin bronze castings (LBC) Oil-less bearing (more than HB 210)	s250	§250	§500

Article 26. Mechanical Efficiency & Coefficient of Friction of Each Part of the Gate Hoist

The mechanical efficiency and coefficient of friction of each part of the gate hoist shall be in accordance with those values listed in Table 2.26-1 and Table 2.26-2.

Table 2.26-1 Mechanical Efficiency of Each Part

Driving pan	Mechanical efficiency (°7o)
Per sheave (plain bearing)	0.95
Per sheave (roller bearing)	0.98
Drum	0.95
Spur gear and bevel gear
per set Open (bearing inclusive).	0.95
Oil bath (bearing inclusive)	0.97
Chain-driving-chain-wheel per piece	0.95

Table 2.26-2 Coefficient of Friction

Friction type	Coefficient of friction
Screw surface of spindle	0.2
Screw surface of worm gear	0.06 - 0.1

Description:

This Article specifies the standard values for the mechanical efficiency and coefficient of friction at each part of the gate hoist. These mechani­cal efficiencies and coefficients of friction will vary with the lubricating condition, ambient temperatures and operating hours, and thus will re­quire proper determination dependent upon use conditions. When a spe­cial mechanical element is used, the setting should be made in accordance with this Article.

Total efficiency of sheaves can be obtained from the formula in Table 2.26-3 and the values in Table 2.26-1

Table 2.26-3 Total Efficiency of Sheaves and Winding Load

(a) Odd number of sheaves	(b) Even number of sheaves
////?////	2ZZZZZZZ
A T	ft ft
0	■ u y t
Q	Q
	e" -1
0 (rt+DKe-l)	n° ne(t - 1)
T = —-—	7- = _2_
(n+ l)n0	™lo

where t]₀: Total efficiency of sheaves

n: Total number of sheaves

e: I/77

77: Efficiency of one sheave

Q: Hoisting load (tf)

T: Rope winding load (tf)

Article 27. Capacity and Time Rating of Prime Mover

1. Motor capacity shall be more than 100% of the calculated operating power, starting torque shall be more than 200% of the motor’s rated torque, and maximum torque shall be less than 300%.

2. The motor’s time rating shall be more than the time required for opera­ting the total lifting height and more than the time required for one operation.

3. In case of frequent, repeated starting and stopping by means of auto­matic control, the motor shall be trouble-free even if repeated opera­tion is conducted for many hours.

4. An internal combustion engine directly connected to the gate hoist shall be of a capacity greater than 150% of the calculated operating force.

Description:

A 3-phase induction motor of the special squirrel cage type is generally used for the hydraulic gate hoist, and its capacity is determined from the operating force.

Description:

The fleet angle of the rope is specified in this Article in order to pre­vent the rope from being unevenly spooled onto the drum when horizon­tally winding up a hydraulic gate using two wireropes.

The number of layers of spooled rope on the drum should satisfy the above fleet angle and should be decided by considering the lifting height of the gate leaf, the wraps of rope in each layer, and the space of the gate hoist. Rope life may be shortened because of unevenly overlapped rope at a layer-changing portion and thus two or fewer layers are often em­ployed.

It should be noted that the torque and hoisting speed may change as the diameter changes with the number of jayers of spooled wirerope.

The wall thickness of the drum can often be obtained from the follow­ing formula:

where ti Mean wall thickness of a drum (cm)

K\ Layer factor (1.0 for one layer; 1.7 for two layers; 2.2 for three layers; 2.4 for four layers; 2.6 for five layers; 2.7 for six layers)

T_Q: Static operating load applied to wirerope (kgf) u: Circumferential allowable compressive stress of a drum (kgf/cm²)

Pt Groove, pitch of a drum (cm)

The rope end spooled onto the drum should be securely fixed so that the rope cannot be removed from the drum by pressing it in with a clip or by filling socket metal through a wirerope.

Article 32. Type and Capacity of Auxiliary Power Equipment Auxiliary power equipment should be of such a system and capacity that it operates the leaf gate without failure as specified.

Description:

1 . Auxiliary power equipment should be decided after a thorough study of the importance of the hydraulic gate.

Types commonly used are as follows:

(1) Motor for Gate Operating Power

also depends on its type.

A larger diameter for the drum and sheave is preferable for safety in the use of wireropes and more than 20 times the wirerope diameter (JIS No. 6) is specified for an overhead crane at a power station. How-.

. ever, for a hydraulic gate, since its normal operating frequency is low and the wirerope winding speed and impact are relatively small, the diameter has been set at more than 19 times the wirerope diameter for the drum diameter, and more than. 17 times for the sheave diameter.

2. Since the use hours, frequency of use, winding speed and impact of the wirerope of a hydraulic gate are relatively low, it is desirable to use a cross-laid wirerope that has a good anti-corrosive nature; partic­ularly JIS No.6 6 x 37 which has the best anti-fatigue property among wires of the same type.

3. For a hydraulic gate such as a self-controlled gate or a navigation lock which is frequently operated, wirerope having a good anti-fatigue property (repeated bending fatigue) is preferable. Therefore, it is prefer­able to use a filler type (JIS No. 13 6 x Fi (29)) or Warlington seal type (JIS No. 21 6 x (36)) wirerope, both of which have excellent anti-fatigue properties and are parallel-laid to prevent deformation. In this case, rope life (anti-fatigue property) for the 6 x Fi (29) is about 3 times that of the cross-laid wirerope (JIS No. 6 x 37), and for the 6 x WS (36) about 6 times that of the cross-laid wirerope. Wirerope that has good anti-fatigue properties and which is easily visually in­spected, e.g. 6 x WS (36) should be selected.

4. It should be noted that the wirerope of a submerged gate may be vi­brated due to discharge water, with debris in the water hooked to the rope.

Article 31. Number of Spooled Wircrope Layers, Fleet Angle and Minimum Number of Wraps

1. The fleet angle of a wirerope shall be within the values listed in Table 2.31-1.

Table 2.31-1. Fleet Angle

Drum	Single layer	Multi layer
Without groove	2°	2’
With groove	4°	2°

2. The minimum number of wraps shall be three or more, and the rope end shall be properly fixed to the drum.

1. Supplied from an auxiliary generator directly connected to an internal combustion engine in case of failure of the firm power source.

2. Operated manually or by an internal combustion engine directly connected to the gate hoist in case of a failure of the motor.

(2) Internal combustion engine for gate operating power Operated manually in case of a failure of the internal combus­tion engine.

2. The capacity of the auxiliary power equipment should be such that the gate is able to operate exactly as proposed. The capacity of the aux­iliary generator should be sufficient to withstand the starting power of the motor, the lighting power and other necessary loads.

3 . If an internal combustion engine is used as an auxiliary power source - directly connected to the gate hoist, a small one is preferred due to its arrangement and therefore approximately 0.05 — 0.1 m/min is com­monly employed as a gate hoisting speed.

Article 33. Capacity of an Oil Hydraulic Pump and a Prime Mover

The design pressure and design oil volume of a hydraulic gate hoist shall -be less than 80% and 90%, respectively, of the rating delivery pressure and the rating discharge of the oil hydraulic pump. The prime mover’s capacity for driving the pump shall be sufficient for the planned perfor­mance of the pump.

Description:

.Considering pressure-proofness and oil leakage, extremely high pres­sure is not preferable for an oil hydraulic hoist in a gate and thus the rat­ing delivery pressure of an oil hydraulic pump is often set at 70 kgf/cm² or 140 kgf/cm².

These oil hydraulic hoists are likely to be left as they are and so the design pressure has been specified as less than 80% of the rating delivery pressure of an oil hydraulic pump after taking into account (1) the loss inside the hydraulic pipes, (2) the friction loss of the packings, (3) the weight of movable parts and (4) the back pressure.

The design pressure was fixed at less than 90% of the rating delivery volume of the oil hydraulic pump, taking into consideration the decrease of volume efficiency of the oil hydraulic pump and leakage from the oil hydraulic valves.

When using a hydraulic motor for an oil hydraulic gate hoist, the start­ing power of the hydraulic motor should be decided by considering the mechanical efficiency of the motor, the speed of the driven parts, the in­ertial force' of the reduction mechanism, etc.

Standard Values for Loss of Pressure given in JIS are as listed in Table 2.33-1.

Pressure loss inside the. pipe is influenced by the pipe length and di­ameter, the viscosity of the oil used, etc., therefore, it is necessary to de­termine the pressure loss by computation, considering the above mentioned items.

As the viscosity of the oil used in a cold region becomes higher, special consideration for the pump capacity and resistance in piping systems is required. •

Table 2.33-1 Pressure Loss by Type of Packings

Shape of piston ring & packing	Minimum operating pressure
	(A)	(B)
O.X. ring/L.U.S. packing	3 kgf/cm2	Rating delivery pressure x 4 % 1
V-packing	5 kgf/cm2	Rating delivery pressure x 6 %
Piston ring	1.5 kgf/cm2	Rating delivery pressure x 1.5%

Use (A) or (B) whichever is greater.

The prime mover that drives an oil hydraulic pump should have a ca­pacity just larger than the maximum required axial input of the pump. Generally, since the total load does not work on the prime mover when the oil hydraulic pump is started a starting torque is not specified.

Article 34. Oil Hydraulic Cylinder

The internal diameter required for an oil hydraulic cylinder shall be de­termined from the gate operating force and the design pressure. The tube thickness of the oil hydraulic cylinder shall be determined from the fol­lowing formula:

PD

¹ ~ 20Qa_o ^{+ a}

where t: Minimum wall thickness of the tube (mm)

P: Rating delivery pressure (kgf/cm²)

D: Internal diameter of the tube (mm)

a_fl: Allowable stress = —^e-y~n^gth (kgf/mm²)

a: Corrosion allowance (mm)

Description:

The above calculation formula is derived from a formula used for the pressure test of a steel pipe and the safety factor for allowable stress was set at 5. •

As the corrosion allowance, it is desirable to take the same value as the corrosion allowance of the gate leaf in cases where the inspection and coat­ing of the cylinder are difficult.

Article 35. Oil Hydraulic Pipe

1. For an oil hydraulic pipe, carbon steel pipes for pressure service JIS G3454 or carbon steel pipes for high pressure service JIS G3455 shall be used and the joint shall be perfectly connected so that no oil leak is produced. .

2. For the expansion point in concrete or for expansion due to tempera­ture change, an expansion joint or other proper measure shall be provided.

,3 . The internal diameter shall be decided so that the flow velocity inside the oil hydraulic pipe is not excessive.

4. The oil hydraulic pipe shall be cleaned by using flushing oil after the oil hydraulic piping work is completed.

5 . When installing multiple oil hydraulic cylinders on one gate, consider­ation shall be given so that the cylinders can work together in a syn­chronized manner.

f '

Description:

Steel pipes for Oil hydraulic piping should be stored in good condition so that they neither become rusty nor contaminated with dust. After pip­ing work, the pressure test should be run by applying a pressure of 1.5 times the rating pressure for more than two minutes arid the pipes should be checked for any oil leaks or deformations. In piping work, it is neces­sary that the pipes be completely embedded in the concrete so that corro­sion can be prevented, or that an external coating can easily be applied if the pipes are exposed. A careful oil leak pressure test should be run before the pipes are embedded in the concrete.

The following values are recommended as the flow velocity in an oil hydraulic piping system:

Pump suction side less than 1.5 m/s

Pump pressure side less than 4.0 m/s

Whenever oil is supplied after repair and when the piping system is newly installed, scales, slugs, water, dust, and sand should be removed from the steel pipes and a thorough cleaning should be made by using good flush­ing oil in order to avoid malfunctions of the hydraulic equipment. When piping to multiple oil hydraulic cylinders on one gate some means should be provided to enable the cylinders to work together in synchronization so that the pressure loss can be equalized.

Article 36. Hydraulic Operating Fluid

Suitable hydraulic operating fluid shall be used by taking into account the type of pump, the working pressure, the working temperature range¹ and the durability.

Description:

Except in special cases, hydraulic operating fluid, mostly of the petro­leum type, should have the proper viscosity and good properties such as oxidation stability, anti-emulsification, fluidity, anti-corrosiveness and dur­ability, frothlessness, and imflammability resistance.

In a cold region, hydraulic operating fluid with good fluidity at low temperatures, i.e. with a pour point of at least 10°C lower than the mini­mum working temperature, is required.

In case of use at a wide ranges of temperatures, the hydraulic opera­ting fluid should have a high viscosity index; generally 90 to 150 would be appropriate.

The fluid temperature in an oil tank should be kept at less than 55°C and the maximum local fluid temperature in the hydraulic piping system should be kept at less than 80°C. The fluid temperature tends to increase when an automatic regulating gate is used frequently and thus the fluid quantity must be increased or a fluid cooling system must be installed. The lowest temperature limit should be approximately -20°C and when it is used at such a temperature it is desirable to operate the oil hydraulic pump for many hours, i.e. to warm it up or a heating system should be placed in the fluid tank.

Article 37. Safety Device and Auxiliary Facilities for Gate Hoist

The following safety devices and auxiliary facilities shall be provided,

t

as appropriate, for a gate hoist:

1. Limit switch

2. Emergency limit switch.

3. Overload protector

4. Gate resting device

5. Gate inclination adjusting device

6. Gate position indicator

7. Detection device for wirerope slackening

8. Detection device for wirerope dislocation

9. Wirerope adjusting device

10. Interlock device

Description:

The general combination of hoist types and safety devices and auxiliary facilities is listed in Table 2.37-1 for reference.

Table 2.37-1 The General Combination of Safety Devices and' Auxiliary Facilities

Types of hoists

Types of safety devices « & auxiliary facilities	Electric hoist			Oil hydraulic hoist
	Wirerope winding type	Screw spindle type	Rack gear type		Cylinder type	Cylinder • wirerope type	Oil hydraulic motor wirerope type
1. Limit switch	O	O	0		O	O	O
2. Emergency limit
switch	kJ	kJ					kJ
3. Overload protector	o	o	. O		O	O	o
4. Gate resting device	o		O		O	O	o
5. Gate inclination
adjusting device	kJ					kJ	kJ
' 6. Gate position in­dicator	o	o	O		O	o	o
7. Detection device for	' r~\					/-x
wirerope slackening	u					CJ	o
8. Detection device for							r~\
wirerope dislocation	kJ					o	o
9. Wirerope adjusting device	o		—		—	o	O':
10. Interlock device	o	o	o		o	o	O

1. Limit Switch

This switch is used to automatically stop the gate at its upper and lower traveling limits and should be maintained in excellent water-proof and dust-proof condition and operated exactly as planned.

2. Emergency Limit Switch

This switch is used for operations when the limit switch is out of order and is generally the same type as the limit switch.

3. Overload Protector

This protector is used to automatically shut off the power when an overload is generated in the hoist. When an internal combustion en­gine is used for gate operating power, this protector is not required.

An overcurrent relay, torque limit detector, sliding clutch, shear pin, buckling protector, etc. are commonly used for a rope winding type, screw spindle type, and rack gear type. For a shear pin, consideration should be given so that the gate leaf does not lower under its own weight even if the pin is broken.

A relief valve is generally provided for a hydraulic cylinder type and hydraulic cylinder wirerope type.

4. Gate Resting Device

This device is used to rest the gate leaf on for a long time for repairs and for checking the hoist and leaf. Manual or automatic operation is required.

Hooks are used for a wirerope winding type, and hooks or screws are used for a hydraulic cylinder type or hydraulic cylinder wirerope type. A method for fixing a rack gear with wedges is commonly used- for a rack gear type.

5. Gate Inclination Adjusting Device

A differential synchronizer is generally used to adjust the gate incli­nation when one gate leaf is lifted up by two gate hoists.

6. Gate Position Indicator

This indicator is used to detect the opening position of the gate leaf either from a rotation of the gear shaft or directly from the traveling of the gate. An indicator suitable for the gate to be controlled should be used.

It is desirable for a display to be provideEhat the side of the hoist when it is locally operated and at the side of the hoist and on the re­mote control panel when it is remote-operated. Both analog displays and digital displays should be available.

An A/D converter, potentiometer, and syncro selsyn are generally used for transmitting the signals from a position detector to a position indicator. - -

7. Detection Device for Wirerope Slackening and Dislocation

-. For a hydraulic gate operated with wirerope, the wirerope may slacken or dislocate from the sheave because of foreign matter lodged / within, thus it is desirable to install a detection device for wirerope slack-, ening ^nd dislocation.

8. Wirerope Adjusting Device ... .

As an adjusting device, a screw type (turnbuckle type) is generally’ provided at the end of a wirerope to adjust the wirerope length on both the right and left sides.

9. Interlock Device

An interlock device should be provided for the gate hoist to prevent accidents due to misoperation or overlapping operations. Various types of interlock devices are available:

1. When both local and remote control are possible, the local control should have priority and remote control should not be possible dur­ing local control.

2. When control is by switching gate operating power, the second operating power should not work while the first operating power is working.

3. When the gate leaf is held by the resting device, the closing opera­tion should not be possible.

0. Others

Instruments and displays necessary for the purposes of the use of the gate should be provided on the control panel. A protective cover should be provided for the gate hoist in order to prevent accidents, as required.

Section 3 Design Particulars