摘要:
A cooling device is provided with an inverter compressor. Set speeds of the inverter compressor can be switched to six stages from a first speed to a sixth speed. The relationship between each of the set speeds of the rotational speed is set so that the stages adjacent to each other have gradually larger differences in rotational speed as the rotational speed becomes higher. With this, independently from the level of the rotational speed, a degree of increase in cooling performance between each of the stages can be equalized. In a case of performing a control to increase or decrease the rotational speed of the inverter compressor stage by stage depending whether an actual temperature drop rate is larger or smaller than a target temperature drop rate, the change amounts in cooling performance that can be substantially equalized, and too high or too low cooling performance does not result, i.e. fluctuation in cooling performance can be minimized. Thus, control to drop the internal temperature in accordance with a predetermined cooling characteristic can be stably performed.
摘要:
An on-line roll grinding method for a work roll, which can decrease an overshoot, by which the pressing load of a rotating grinding wheel on a work roll exceeds a set grinding pressing load, is provided. This method is an on-line grinding method for a work roll, adapted to press a rotating grinding wheel (3a) having elasticity against a work roll (1) of a rolling mill to grind the work roll, wherein when the pressing load of the rotating grinding wheel (3a) reaches a set load F, which has been set beforehand, after the rotating grinding wheel (3a) contacts the work roll (1), the forward velocity of the rotating grinding wheel (3a) is reduced to decrease an overshoot by which the pressing load of the rotating grinding wheel (3a) on the work roll (1) exceeds a set grinding pressing load F0.
摘要:
A storing section 49 stores data of a pull down cooling characteristic indicative of a time-varying mode of reduction in a target temperature drop. For example, when this is a linear function line xp, a target internal temperature drop degree takes a constant value Ap, irrespective of an operating time. An actual temperature drop degree Sp is computed on the basis of the detected internal temperature. The computed value Sp is compared with a target value Ap read from the storing section 49. When the computed value Sp is less than the target value Ap, a rotational speed of an inverter compressor 32 is increased via an inverter circuit 55. When the computed value Sp is larger than the target value Ap, the rotational speed of the compressor 32 is decreased. The speed increases and decreases are repeated so that pull down cooling is performed along the linear line xp.
摘要:
A rolling mill, a gap-removing apparatus for roll bearing boxes, a rolling method, a modifying method for a rolling mill, and hot finish tandem rolling equipment are provided with roll bearing boxes for rotatably supporting work rolls in a housing, a first pushing device for applying a vertical balancing force or bender force to the work rolls through the roll bearing boxes, and a second pushing device for applying a pushing force in a direction orthogonal to the work roll axis in a horizontal plane to the roll bearing boxes. The first pushing device and the second pushing device are disposed to be offset from each other in the work roll axis direction. In certain arrangements, the second pushing device is disposed between a plurality of the first pushing devices in the work roll axis direction. Gaps at the roll bearing boxes in the rolling mill can be removed without enlarging the equipment in size.
摘要:
A small steam generator uses a cylindrical steam generation vessel having a steam generation portion formed to store an amount of water for generating steam and a steam passage portion formed on the upper end of the steam generation portion for spouting steam generated in the steam generation portion. A heater element is disposed within the steam generation vessel, and an induction heating coil is wound around the periphery of the steam generation vessel for energizing the heater element. The heater element is energized by supply of electric power to the heating coil so that steam generated by boiling of the water in the steam generation portion spouts upward from the steam passage. In the steam generator, a steam discharge duct is mounted on the upper end of the steam passage for receiving the steam spouting upward from the steam passage and to discharge it in a lateral direction such that drops of hot water adhered to a ceiling surface of the discharge duct fall and re-circulate back into the steam generation part.
摘要:
Provided is an inexpensive and compact cooling device which does not increase the circulation resistance of a refrigerant, filling quantity of a refrigerant in a natural circulation circuit wherein natural convection of the refrigerant is caused by using a thermo-siphon, and cross-sectional areas of individual passages while maintaining a desired cooling efficiency in the circuit. A secondary cooling device (40) includes a secondary heat exchange section (42) of a cascade heat exchanger (HE) which liquifies a gaseous-phase secondary refrigerant, and an evaporator (EP) which vaporizes a liquid-phase secondary refrigerant. The secondary cooling device (40) is provided with a plurality of natural circulation circuits (48) equipped with liquid pipings (44) and gas pipings (46) which connect the secondary heat exchange section (42) and the evaporator (EP). The evaporator (EP) has evaporation passages (52) of the natural circulation circuits (48) provided in layers vertically apart from one another. The evaporation passage (52) is formed by a spiral fin tube type heat exchanger whose fins are spirally wound on the outer circumference of an evaporation pipe through which the secondary refrigerant circulates.
摘要:
In controlled cooling operation, data on the controlled cooling operation characteristics is read out from a memory and compared with a drop degree of an inside temperature actually measured by an inside temperature sensor 46, and a cooling device is operated so that the inside temperature drops following a temperature curve stored in advance. A state where the inside temperature is higher than the set temperature by 7 K or more lasts for 15 minutes, for example, the cooling capacity by the cooling device is increased than the cooling capacity based on control of a controlled operation controller so that even if a door 17 is frequently opened/closed and the inside temperature tends to gradually rise, it can be detected at an early stage and kept close to the set temperature.
摘要:
PROBLEM TO BE SOLVED: To provide a cooling storage, in which a refrigerant from one compressor is selectively supplied to multiple evaporators respectively disposed in multiple storage rooms having different thermal loads, and prevent any temperature rise of a storage room of higher thermal load.SOLUTION: The liquid refrigerant from the compressor 20 and the condenser 21 is alternately supplied to the cooling device for the freezing room 27F and the evaporator for the refrigeration room 27R through the three-way valve 24, so that the freezing room and the refrigeration room are alternately cooled. Even if any one of the freezing room 13F and the refrigeration room 13R reached the lower limit set temperature on ahead, the freezing room 13F (the storage room of higher thermal load) is always cooled last and certainly cooled until it reaches the lower limit set temperature.
摘要:
Deviation calculating means 42 calculates a deviation between an internal temperature detected by a temperature sensor 35 and a target temperature provided from target temperature setting means 41 for each predetermined time period. The deviation is integrated by deviation integrating means 46. When the integrated value exceeds a predetermined reference value, a rotational speed of an inverter motor that drives a compressor is increased. Therefore, for example, even if an internal temperature temporarily rises because a door is opened temporarily and outside air flows into a storage compartment, because there is no sudden change in the integrated value of the temperature deviation and the rotational speed of the compressor does not react in an oversensitive manner and rapidly increase. Consequently the control is stable. Thus, an unnecessarily oversensitive response to a sudden change in an internal temperature can be prevented, enabling operation at a higher efficiency.
摘要:
A cooling apparatus which stably cools a target. The cooling apparatus includes a primary circuit that has a first heat exchanging section which is provided at a heat exchanger, and vaporizes a liquid-phase primary coolant to be a gas-phase primary coolant, and a condenser which condenses the gas-phase primary coolant to be the liquid-phase primary coolant, and lets the liquid-phase primary coolant flow to the first heat exchanging section from the condenser through a liquid piping and lets the gas-phase primary coolant flow to the condenser from the first heat exchanging section through a gas piping. The cooling apparatus further includes a secondary circuit having a second heat exchanging section, an expansion valve, an evaporator, and a compressor connected together by a coolant piping.