摘要:
A brake or clutch lining (10; 12) has a friction lining (22) arranged on a carrier plate (20). For purposes of detecting a critical operating temperature, an electrically conductive material (24) that has a phase-transition temperature that falls within the range of the critical operating temperature of the friction lining to be detected is provided in at least one place in the friction lining (22).
摘要:
The invention relates to a method and a device for the production of two-channel or multi-channel pulse-width-modulated rectangular pulses. According to the invention, exactly one pulse is discharged within a period in each channel. The inception of a pulse in relation to the moment of inception is delayed by an actual dead time. The dead time is respectively kept constant for at least one period and a new value for the dead time is produced for a modulation of the pulse width and/or a new value is produced for the duration of the period and the actual dead time and/or the actual duration of the period is set at the beginning of the desired period according to the new value of the dead time and/or duration of the period.
摘要:
Flowable devices provide communicate between surface and downhole instruments. The flowable devices having unique addresses are introduced into the flow of a fluid flowing in the wellbore. The flowable devices are used for providing information to a downhole controller and/or retrieving information from a downhole device.
摘要:
A method and apparatus for generating an AC voltage in a system frequency range from a DC input voltage. Two opposite-pole, pulse-width modulated (PWM) rectangular pulses having a high switching rate are applied to the primary winding of a transformer. Every pulse is modulated to correspond to a half-wave of the AC voltage to be generated. On the secondary side of the transformer, the impulses of both PWM pulse trains are rectified to create a pulse train of a single polarity, the pulse width modulation of which corresponds to subsequent half-waves of the AC voltage to be generated. The pulse train so obtained is periodically commutated at double the frequency of the AC voltage to be generated so that a PWM signal representative of the AC output voltage is obtained with respect to amplitude, frequency, and polarity.
摘要:
This invention relates to flowable devices and methods of utilizing such flowable devices in wellbores to provide communicate between surface and downhole instruments, among downhole devices, establish a communication network in the wellbore, act as sensors, and act as power transfer devices. The flowable devices are adapted to move with a fluid flowing in the wellbore. The flowable device may be memory device or a device that can provide a measure of a parameter of interest or act as a power transfer device. The flowable devices are introduced into the flow of a fluid flowing in the wellbore. The fluid moves the device in the wellbore. If the device is a data exchange device, it may be channeled in a manner that enables a device in the wellbore to interact with the memory device, which may include retrieving information from the flowable device and/or recording information on the flowable device. The sensor in a flowable device can take a variety of measurement(s) in the wellbore. The flowable devices return to the surface with the returning fluid.
摘要:
An apparatus and method are disclosed for obtaining samples of pristine formation or formation fluid, using a work string designed for performing other downhole work such as drilling, workover operations, or re-entry operations. An extendable element extends against the formation wall to obtain the pristine formation or fluid sample. While the test tool is in standby condition, the extendable element is withdrawn within the work string, protected by other structure from damage during operation of the work string. The apparatus is used to sense or sample downhole conditions while using a work string, and the measurements or samples taken can be used to adjust working fluid properties without withdrawing the work string from the bore hole. When the extendable element is a packer, the apparatus can be used to prevent a kick from reaching the surface, adjust the density of the drilling fluid, and thereafter continuing use of the work string.
摘要:
The invention relates to a method and a device for the production of two-channel or multi-channel pulse-width-modulated rectangular pulses. According to the invention, exactly one pulse is discharged within a period in each channel. The inception of a pulse in relation to the moment of inception is delayed by an actual dead time. The dead time is respectively kept constant for at least one period and a new value for the dead time is produced for a modulation of the pulse width and/or a new value is produced for the duration of the period and the actual dead time and/or the actual duration of the period is set at the beginning of the desired period according to the new value of the dead time and/or duration of the period.
摘要:
A formation pressure testing while drilling device on a bottomhole assembly makes measurements of fluid pressure during drilling of a borehole. Based on the pressure measurements, drilling direction can be altered to maintain the wellbore in a desired relation to a fluid contact. Acoustic transmitters and/or receivers on the bottomhole assembly can provide additional information about bed boundaries, faults and gas-water contacts.
摘要:
An apparatus and method for obtaining samples of pristine formation or formation fluid, using a work string designed for performing other downhole work such as drilling, workover operations, or re-entry operations. An extendable element extends against the formation wall to obtain the pristine formation or fluid sample. While the test tool is in a standby condition, the extendable element is withdrawn within the work string, protected by other structure from damage during operation of the work string. The test apparatus is mounted on a sliding, non-rotating, sleeve on the work string.
摘要:
An apparatus and method for obtaining samples of pristine formation or; formation fluid, using a work string designed for performing other downhole work such as drilling, workover operations, or re-entry operations. An extendable element extends against the formation wall to obtain the pristine formation or fluid sample. The apparatus includes at least one extendable gripper element for anchoring the apparatus during testing and sampling operations.