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1. 发明专利

JP2000337288A CAVITATION DETECTING METHOD 失效
公开(公告)号：JP2000337288A
公开(公告)日：2000-12-05
申请号：JP14278499
申请日：1999-05-24
申请人： HITACHI LTD
发明人： KOGA MASAAKI , MAEDA ISAMU , TAKAHASHI JIRO
IPC分类号： F04D15/00 , F04D29/66
摘要： PROBLEM TO BE SOLVED: To improve cavitation detecting accuracy by fitting a vibration detecting pickup to a machine to be measured, and discriminating the generation of cavitation of an operating fluid of the machine to be measured when the bispectrum value of the detection value of the pickup is outside a fixed range. SOLUTION: A vibration detecting pickup is fitted to a machine to be measured which is a fluid machine such as a pump, and cavitation of an operating fluid of the machine to be measured is monitored on the basis of the detected value of the pickup. At this time, an output signal of the vibration detecting pickup is inputted to a fast Fourier transformer (FET) 2. Bispectrum is obtained in a computer 3 from the output data of the FET 2, and the generation of cavitation is discriminated when the obtained bispectrum value is outside a fixed range. The analyzed result of the bispectrum is outputted from a printer 4.

2. 发明专利

JPH10281832A PULSE DOPPLER TYPE ULTRASONIC FLOWMETER 失效
公开(公告)号：JPH10281832A
公开(公告)日：1998-10-23
申请号：JP8908897
申请日：1997-04-08
申请人： HITACHI LTD
发明人： ANZAI YOSHIRO , YAZAWA SETSUO , OKAMURA TOMOYOSHI , KOGA MASAAKI
IPC分类号： G01F1/66
摘要： PROBLEM TO BE SOLVED: To enhance accuracy in the measurement of flow rate by neglecting a current A in the vicinity of the pipe wall on the receiver side where the measurement accuracy is low and determining a current distribution data C in the vicinity of the pipe wall from a current distribution data B detected with high accuracy from a part other than the vicinity of the pipe wall and then calculating the flow rate from the current distribution data B and C. SOLUTION: In the region Xm remote from the pipe wall, effect of noise reflected on a boundary face is suppressed and a normal current distribution B is detected. A current distribution indicator/corrector sets a normally detected current distribution B positive and extrapolates the positive current distribution B on the region Xm side thus determining a current distribution C by numeric analysis. The current distribution is approximated by a quadratic or cubic curve by a method of least squares, for example, and the current in the region Xm is extrapolated using that curve to obtain a current distribution as shown by a dashed line C. A flow rate calculator calculates the flow rate from the corrected current distributions b and C according to a specified formula.

3. 发明专利

JPS51103387A 失效
公开(公告)号：JPS51103387A
公开(公告)日：1976-09-11
申请号：JP2803075
申请日：1975-03-10
申请人： HITACHI LTD
发明人： KOGA MASAAKI , BABA NOBUYUKI
IPC分类号： B21B15/00 , B23D15/04 , B23D33/02

4. 发明专利

JPH11132182A PUMP INSIDE LIQUID LEVEL DETECTOR FOR HORIZONTAL SHAFT PUMP 失效
公开(公告)号：JPH11132182A
公开(公告)日：1999-05-18
申请号：JP29669197
申请日：1997-10-29
申请人： HITACHI LTD
发明人： KOGA MASAAKI , TSUNEMITSU AKIRA , MATSUI SHIRO
IPC分类号： G01F23/30 , F04D15/00
摘要： PROBLEM TO BE SOLVED: To prevent it from erroneously detecting that a water level lowers when a float lowers by a stay of bubbles by constituting so that a pump pumping-up liquid containing bubbles is discharged by introducing it to upper connecting piping from lower connecting piping of a detector by differential pressure in a connecting position of the detector. SOLUTION: When a horizontal shaft pump 1 is operated, a pumping liquid is sucked in the pump 1 from suction piping 8, and is discharged from delivery piping 9 by increasing pressure by rotation of an impeller. In this case, when connecting a float type liquid level detector 2 attached to the horizontal shaft pump 1, it is connected by upper and lower connecting piping 4 and 5 communicated with an intake port 6 higher than a height of an underwater bearing and an intake port 7 lower than a height of the underwater bearing so that a pumping liquid of the horizontal shaft pump 1 is introduced upward from below the liquid level detector 2. In this case, the upper connecting piping 4 is set as an upward gradient from the liquid level detector 2 to the intake port 6, and the lower connecting piping 5 is set as an upward gradient from the intake port 7 to the liquid level detector 2, and a stay of bubbles in the liquid level detector 2 is prevented.

5. 发明专利

JP2000018464A DOUBLE TUBE-TYPE BRANCH PIPE 失效
公开(公告)号：JP2000018464A
公开(公告)日：2000-01-18
申请号：JP18856798
申请日：1998-07-03
申请人： HITACHI LTD
发明人： KOBAYASHI YOSHIO , KOGA MASAAKI
IPC分类号： F16L41/02 , F16L45/00
摘要： PROBLEM TO BE SOLVED: To clean a branch part during the transportation of the fluid in a base pipe by forming the branch part by the combination of a double pipe comprising an outer cylinder connected to the base pipe and an inner cylinder demountable from the branch part for its cleaning, and a separation valve connected to the outer cylinder for separation. SOLUTION: In the cleaning of a branch pipe, a bolt 11 and a nut 12 for guiding the inner cylinder ejection, and an inner cylinder ejection bolt 13 are inserted into an inner cylinder flange 3 and an outer cylinder flange 7, the bolt and nut for fastening the flange are demounted, a nut 12 for the inner cylinder ejection bolt is gradually loosened, an inner cylinder 2 is ejected while screwing the inner cylinder ejection bolt 13, and a ball valve 1 for separation is completely closed and the inner cylinder is completely ejected in a stage when one packing sealing the inner cylinder and the outer cylinder can be seen. A bolt 5 for fastening an inner cylinder closing plate is loosened to demount an inner cylinder closing plate 4, whereby the inner and outer surfaces of the ejected inner cylinder 2 can be cleaned. The ball valve for separation 1 has high structural workability, and the foreign matters are hardly entraped between a valve element and a valve seat, so that the cleaning of the ball valve 1 is almost unnecessary.

6. 发明专利

JPH10239127A METHOD AND DEVICE FOR DETECTING FLOW RATE OF FLUID MACHINE 失效
公开(公告)号：JPH10239127A
公开(公告)日：1998-09-11
申请号：JP3922097
申请日：1997-02-24
申请人： HITACHI LTD
发明人： OKAMURA TOMOYOSHI , YAMADA MASAYUKI , KATAKURA KAGEYOSHI , KOGA MASAAKI
IPC分类号： G01F1/66
摘要： PROBLEM TO BE SOLVED: To provide a method and device for detecting the flow rate of fluid machine that can detect the flow rate of an already existing fluid machine with high accuracy at a low cost. SOLUTION: In the method for detecting flow rate of fluid machine, in which the flow rate Q of a fluid in at least one cross section of a flow passage in a fluid machine or flow passages before and after the fluid machine is detected, the acoustic velocity C in the fluid at the objective cross section or its vicinity is detected by means of an ultrasonic current meter 102 for detecting acoustic velocity and the velocity distribution V(x) at the objective cross section is detected by means of a pulse Doppler type ultrasonic current meter for detecting flow velocity. Then, the flow rate Q is calculated by using the velocity distribution V(x) and the cross-sectional area of the objective cross section.

7. 发明专利

JPS5134853A 失效
公开(公告)号：JPS5134853A
公开(公告)日：1976-03-24
申请号：JP10674474
申请日：1974-09-18
申请人： HITACHI LTD
发明人： KOGA MASAAKI , FUKUI KAKICHI
IPC分类号： B21B39/20 , B65G47/248 , B65G47/94

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