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Energy - Saving Application And Selection Basis Of Hydraulic Coupler
Oct 20, 2017

Type and Application Characteristics of Hydraulic Coupler

Hydraulic coupler according to its application characteristics can be divided into three basic types: ordinary type, limited torque type, speed type.

Ordinary hydraulic coupler structure is relatively simple, but the cavity effective volume, high transmission efficiency. Its zero speed torque up to the rated torque of 6 to 7 times, and sometimes even up to 20 times, because the overload factor, overload protection performance is poor. Used for overload protection and speed control does not require the transmission system, from the isolation torsional vibration and shock effect.

The torque-type hydraulic coupler adopts the structural measures to limit the torque when the low gear ratio increases, which solves the problem that the overload factor of the common type hydraulic coupler is too large can effectively protect the power machine (and the working machine) Expanding the application of hydraulic couplers.

The variable speed type hydraulic coupler changes the output speed and torque by changing the fill of the working chamber (usually by means of conduit adjustment) in the case of constant input speed, the so-called positive displacement

Section. With the ordinary type, limited torque type hydraulic coupler can be cooling and cooling characteristics of their own different, speed-type hydraulic coupler due to its own structural reasons and its output speed adjustment range, transmission power characteristics, there must be outside the working fluid The circulation and cooling system allows the working fluid to continuously enter and exit the working chamber to adjust the filling and dissipating heat of the working chamber.

     Adjustable hydraulic coupler is divided into import regulation, export regulation, compound regulation. Import adjustable speed control type hydraulic coupler compact structure, small size, light weight, auxiliary system is simple. But because of the shell and the pump wheel rotation and speed control process of working fluid center of gravity of the non-stop changes, resulting in decreased accuracy and vibration increases, it is not suitable for high-speed use, for more than 1500 r / min speed of small and medium power occasion. This kind of hydraulic coupler is difficult to install and debug, the speed response is slow, the failure rate is high, so its production and application are decreasing day by day.

       Adjustable speed control type hydraulic coupler working chamber inlet by the quantitative pump oil supply, the same flow, the outlet flow with the opening adjustment of the catheter changes, resulting in the working chamber fullness and output speed changes. As the speed response fast (ten seconds), it is also known as fast adjustment coupler. It is generally believed that the double beam structure is more advanced, its characteristics: compact structure, light weight, high precision, fast speed response, suitable for high speed and fast speed requirements of the occasion, widely used in fans and other equipment.

       The inlet and outlet flow of the composite adjustable hydraulic coupler working chamber can be adjusted at the same time, although the structure is more complicated, it can reduce the oil pump flow demand and better control the working liquid temperature.

The hydraulic coupler has the following application characteristics.

(1) stepless speed regulation: the fan can adjust the conditions of energy saving. After installing the hydraulic coupler, you can easily adjust the speed by manual or electric remote control to meet the flow requirements of the operating conditions, which can save a lot of energy.

(2) no-load start: hydraulic coupler main and passive shaft between the mechanical connection, the flow of oil in the empty, can be close to the form of no-load quickly start the motor, and then gradually increase the coupler filling The fan gradually started to enter the operating conditions to ensure the safe start of high-power fan, but also reduce the motor power consumption when the start.

(3) overload protection: the coupling between the main and passive shaft is a flexible connection between the slip, you can block the load torque suddenly increase or attenuate the load of the torsional vibration on the impact of the motor to prevent the loss of carving or transmission parts and other accidents The

(4) no harmonic effects: with different levels of high and low voltage, medium and large-capacity motor supporting the use of the motor can always ensure that the rated speed to run, the motor efficiency, high power factor, no harmonic pollution The

(5) long life cycle: In addition to wear-free components outside the bearing, the coupler can be a long time without maintenance and safe operation, improve the use of investment efficiency.

(6) has a slip loss: the hydraulic coupler is attached to the differential speed control device, can not make the load to the rated motor speed, speed of the slip loss in the form of heat to increase the oil temperature, must be distributed or feedback use.

Energy - saving Application and Benefit Analysis of Hydraulic Coupler on Fan

Comparison of 2 and throttle regulation

YO TJ400 speed control type hydraulic coupler, input 1500r / min, power 40kW, the average monthly energy saving 8000kW · h, according to the year 9 months Speed calculation, the annual saving of 70,000 kW · h.

2. Comparison with constant speed operation

Taking steel - making converter dust removal fan as an example. According to the requirements of steelmaking process, when the fan blowing at full speed operation, lead to the production of steel gas recycling. In the non-blowing (tapping, feed) time, do not need to smoke and dust, but the large motor should not be frequent start and stop, still using full-speed operation, so that the fan does not need to smoke and dust to the atmosphere Power consumption. The installation of adjustable speed hydraulic coupler can be applied to the fan speed control, thus saving a lot of power.

A steel factory at constant speed operation of the T18t argon oxygen converter dust removal fan installed speed control hydraulic coupler to achieve a variable speed control operation, the following analysis of its energy efficiency.

The converter blows a furnace steel cycle for 2h, where the blowing time t1 and the tapping feed time t2 each account for 1h (Figure 1).

When the constant speed operation, the motor high speed full power operation, the motor energy consumption

W d = P1 (t1 + t2)

The use of hydraulic coupler speed control operation, the blower when the high-speed operation, tapping, feeding low-speed operation of the fan. Its motor energy is

W 0 = P1 t1 + P2 t2

Where t is the time for the converter blowing (fan high-speed operation), h; t2 for the converter tapping, the feed (fan), the furnace is the high-speed operation of the fan when the motor power consumption, kW; P2 for the low-speed operation of the motor when the motor power consumption, Low speed operation) time, h; t1 = t2 = 1h.

Variable speed adjustment on the fan constant speed operation of energy saving WJ:

WJ = W d - W 0

= P1 (t1 + t2) - (P1 t1 + P2 t2) = (P1 - P2) t2

Where (P1 - P2) t2 is the hatched portion of Fig. In the normal production of the actual calculation (digital process slightly) in the annual energy savings of 637632kW · h, the annual energy saving rate:



Figure 1 converter fan power cycle diagram

3. Hydraulic coupler matching calculation and installation and maintenance

3. 1 match calculation

3. 1. 1 selection

The hydraulic coupler is matched to obtain the motor and work machine

Best supporting performance for the purpose. Three simplified methods are recommended.

(1) look-up table method

According to the work of the machine rated speed and power to check the hydraulic coupler product samples of the relevant map line, parameter table to determine the model, specifications.

(2) Calculate the effective diameter method

The effective diameter of the working chamber of the hydraulic coupler is calculated according to the known conditions. The calculation formula can be derived from the impeller moment equation:

Where MB is the pump wheel torque, MB = 1. 05 MT (N · m) (considering the loss); λB is the pump wheel torque coefficient, check the liquid coupler original characteristic curve i = 0.97 λB value, Calculate the effective diameter D value of the working chamber of the hydraulic coupler, check the table round, by gear selection.

(3) power coefficient method

When the load capacity is uncertain, you can directly press the motor or the rated capacity of the machine to calculate the choice, so that K is the power factor of the coupler; P for the motor

Fixed power or 1. 05 times the working machine shaft power, kW; n for the motor rated speed or when the maximum output speed of the coupler, r / min; D for the coupler working chamber effective diameter, m.

Calculation example: a steel converter dust removal fan power of 520kW, motor power 560kW, speed 960r / min. By comparing the primary YO TGC875 hydraulic coupler, n = 960r / min, P = 400 ~ 960kW

3. 1. 2 cooler selection calculation

The slip loss (and other losses) of the hydraulic coupler during the speed control process will be converted to heat to raise the working oil temperature. Both the torque type and the general type hydraulic coupler are designed with self-cooling capability without worrying, but the cooling system must be configured for the differential loss (heat generation) for the speed control type hydraulic coupler so that the heated working oil enters the cooler Cooling and then back to the coupler working chamber, constitute a cooling cycle.

3. 1. 3 Select the coupling

The hydraulic coupler is installed between the motor and the working machine, and its input and output are connected by coupling. Should be combined with the load situation, the installation environment reasonable choice coupling.

If no special requirements (special requirements should be specially designed), the following conditions can be used to select the standard coupling:

M G = λM ≤ [M]

Where M G is the working torque of the coupling; M is the theoretical torque of the coupling; [M] is the allowable torque of the standard coupling; λ is the working condition coefficient. λ and the nature of the load, the general for small and medium sized fans, λ = 1. 3 ~ 1.5. Important occasions should be calculated by calculation or test.

Select the value of λ should be noted that the size and quality of the coupling increases, will increase the load on the support, causing additional dynamic load increases, so the size of the coupling is sufficient on the line, not necessarily the bigger the better. In the choice of coupling type should be considered: coupler during the work of the heat loss caused by the heat will make its center high, the axial size of the thermal expansion changes,

In the position tolerance, the type of coupling selected should be able to compensate for the amount of change in this size position. Optional elastic pin coupling.

3. 2 Installation and maintenance

In order to ensure the normal operation of hydraulic coupler and extend the service life, should be strictly installed quality. General should pay attention to the following aspects:

(1) to work machine for the installation of the benchmark, motor, coupler hanging

Loading, positioning, coarse after the watering foundation, fine tune after the second watering;

(2) fine tuning to the installation of technical requirements as the yardstick to work machine as a benchmark to find the coupler, and then coupler to correct the motor;

(3) strict adjustment to find the order can improve the efficiency of correction, to ensure correctness. If the working machine, coupler, motor coaxial between the positive accuracy is good, will cause the coupling of the elastic body quickly damaged, and produce vibration and damage the bearings, and even those who will cause the machine shaft bending or fracture;

(4) The mounting axis of the coupler should be lower than the motor and work

Machine axis. This is the center of the reserved heat for the coupler

High expansion, to ensure that the coupler thermal work can be higher

Of the coaxiality, improve operating efficiency.