Self-Sealing Couplings
This coupling allows connection/disconnection of rubber hoses with one-touch operation.
Rubber (plastic) Hoses
Rubber hoses are used when metal-tube connection is not allowed, some moving parts are present, and vibration protection is required. The hose consists of an inner layer, a reinforcement layer, and an outer layer, and couplings are connected to each end. In selecting rubber hose, due consideration should be given to working pressure, working fluid, working temperature, bore, and coupling shape.
Shaft Couplings (Couplings)
These couplings connect a pump shaft and a prime mover. With due consideration to axial misalignment of shafts in hydraulic equipment, the following couplings are available.
(1) Flange-type flexible-shaft coupling: with two flanges, this coupling uses the properties of rubber bush applied as a coupling bolt. Deformation of the rubber eliminates the axial misalignment.
(2) Chain coupling: this coupling connects two shafts with double-lined roller chains, and it uses a sprocket roller, which provides space between feeding crows, to prevent misalignment. This coupling is compact and light, but requires grease as a lubricant.
(3) Rubber/plastic coupling: this coupling is made of rubber or plastic for torque transmission. Its maximum rotation speed and transmittable torque are lower than other couplings. The coupling, however, provides a large misalignment tolerance, high vibration and shock absorption, and low noise.
Automatic Water Supply Valve with a Temperature Detector
The valve automatically opens to supply cooling water and decrease the temperature when a temperature detector placed in a reservoir detects that the working fluid temperature reaches a certain level. Depending on the detected temperature, the valve can adjust the cooling water supply.
Water Solenoid Valve
This valve opens/closes a cooling water supply line. A signal from a thermal switch turns the valve on/off to sustain the working fluid temperature at a constant level.
High Pressure Stop Valves
The glove and ball types are available. These valves can be connected with a screwed connection, flange, and manifold. Various combination valves are available as required by their use.
i . Glove valve
ii. Ball valve
This valve provides low flow resistance and small internal leakage. It can be opened/closed with one-touch operation. A three-way valve is also available.
iii. Combination valves
a) Accumulator stop valve: this valve, designed for accumulator maintenance, serves as a stop valve for the supply and drain lines. It can be connected with a flange or a manifold.
b) Maintenance valve: this valve is used for maintenance of solenoid and relief valves.
Low Pressure Stop Valves
These valves are used in maintenance. The following types are among the selections available for line connections: screwed type and flange type.
i . Ball valve: this valve opens/closes with 90-degree rotation of a knob
ii. Glove valve: this valve has the same structure as the valve for high pressure use
iii. Gate valve: this valve is placed in an inlet line.
Hydraulic Flow Volume Measurement
(1) Oil level gauge: acrylic-bar oil level gauges are widely selected for a general visual inspection. It is possible to attach a thermometer at a lower part of the gauge. A gauge with a shuttle valve or a remotereading
gauge should be used according to the Fire Service Law, if applied.
(2) Oil level gauge with an electric contact: two types are available. One is equipped with an electric contact with a needle for visual inspection, and the other is with an electric contact with a read switch.
(3) Oil level gauge for continuous signal output: generally, two types are available. One is equipped with an electric contact providing continuous signals. It indicates the oil level by a needle for visual inspection. The other type is equipped with a sensor only. The sensor is usually of a resistance type or a magnetorestrictive type.
Thermo Measurement
(1) Thermometer: generally, the following types are available for visual inspection. i . Bar thermometer with a protective tube
ii. Bimetal thermometer
iii. Remote-reading panel-mounted thermometer
(2) Thermometer with an electric contact: the following types are available. i . Thermostat type
ii. Remote-reading thermometer with an electric contact type: the electric contact type and a micro switch type are available.
(3) Thermometer for continuous signal output: generally, this thermometer uses a thermo sensor (temperature detector) to indicate temperatures. The following types of temperature detectors are available. The shape of the detector and setting-up condition should be considered when making the selection.
i . Platinum resistance thermometer
ii. Thermo-couple
iii. Thermistor thermometer
Flow Measurement
(1) Flow meter: a sight flow indicator is used to check whether the working fluid is flowing or not by simple visual inspection. Another type is a cone flow meter or a flapper type flow meter in which a
gauge is embedded.
(2) Flow meter with an electric contact: an electric contact is attached to a cone flow meter or a flapper type flow meter.
(3) Flow meter for continuous signal output: the following types are available. i . Positive displacement flow meter (gear motor)
ii. Turbine flow meter
iii. Ultrasonic flow meter
iv. Differential pressure flow meter
Positive displacement flow meters are widely used in hydraulic equipment. Sometimes, they are comprised of a hydraulic motor and a pulse encoder.
