US 4,774,676 A · Linear digital flowmeter

Abstract

A linear digital flow meter includes a float in a passageway as is located positioned with the rate of flow. A sight glass tube is secured to the end of the unit and a rod connects the float to a tube. A generally H-shaped housing has the tube located in an opening in the cross bar with a light chamber to one side and a detector chamber to the opposite. A bank of LEDs in the light chamber is aligned with a transmitting slot and a bank of phototransistors is aligned with a receiving slot in the detector chamber. A shadow mask between the phototransistors and the slot concentrate the light so the phototransistor receive light according to the length of rod in the sight glass. A bottom connector chamber is in the bottom of the housing with L-shaped passages to the light and detector chambers with the appropriate leads to the lamp and detector chambers. A multiplexer connects the phototransistors to a microprocessor which stores and processes the signal. The microprocessor has a programmable range selection unit, a limit control unit and an output circuit establishing a voltage output signal unit and a current output signal unit to produce voltage and current signals proportional to the flow rate.

Claims21

Dependent claims

A linear digital flow meter, comprising a transparent sight glass tube, a movable indicator position within said sight glass tube in accordance with the flow, a housing mounted to enclose said sight glass tube and establishing a substantial light enclosure about said glass tube, a light bank secured within said housing and establishing a light bar aligned with and passing through said tube, a plurality of individual light sensitive elements arranged in a bar fashion to the opposite side of said tube, a microprocessor coupled to read the output of each of said light sensitive elements and operable to establish a signal linearly proportional to the position of the indicator in said tube, and range selection means connected to said microprocessor for selecting the flow range being monitored.

A linear digital flow meter, comprising

a flow passageway body having a fluid inlet and a fluid outlet with a flow passage connected between the inlet and outlet,
a float assembly disposed within said passageway and positioned within the pasageway in accordance with the rate of flow of fluid through said passageway,
a transparent sight glass tube secured to the one end of said passageway, a rod-like member connected to the float assembly and extended into the sight glass tube and including an indicator securd to the end of said rod-like member within said tube,
an elongated housing secured to the lower end of said body and substantially enclosing said sight glass tube,
said housing having a generally H-shaped cross section with a realtively heavy cross bar including an opening telescoped over said tube, said H-shaped housing defining a light chamber to one side of said tube and a detector chamber to the opposite side of said tube, said light chamber having a light transmitting slot in the cross bar and said detector chamber having a light receiving slot in the cross bar,
lamp means arranged in alignment within said light chamber with said light transmitting slot in the cross bar adjacent the light chamber and transmitting a light beam bar from the light chamber through said tube,
a support mounted within said detector chamber, a plurality of individual light sensitive elements secured to said support within the detector chamber and aligned to define a detecting bar located in alignment with said light receiving slot in said detector chamber to receive light from the tube passing through said slot and into the detector chamber,
a shadow mask supported between said elements in alignment with said light receiving slot whereby said light sensitive elements are illuminated in accordance with the location of said rod-like member in said sight glass tube,
a multiplexing module connected to said support and having a plurality of inputs connected one each to each of said elements and to a plurality of output and control leads for sequentially reading the state of each of said elements and having a common input/output line providing an output signal for each of said elements,
a microprocessor having a programmed means and coupled to said multiplexing module for reading of said output signals,
an A/D converter connected to said microprocessor and having an analog signal line for establishing an output analog signal proportional to the instantaneous level of said output signal,
a voltage output signal means connected to said analog signal line to generate an operating voltage signal providing a voltage proportional to the position of said indicator, and
an electric current drive including a plurality of individual parallel circuits, each of said parallel circuits including a field effect transistor having its main terminals connected in series to the analog signal line and an output means having an amplifying means connecting the field effect transistor to an output port means to establish an electric current signal proportional to the position of said indicator to create an electric current signal proportional to the analog voltage signal.

10 more elements

A linear digital flow meter, comprising

a flow passageway body having a fluid inlet and a fluid outlet with a flow passage connected between the inlet and outlet,
a float assembly disposed within said passageway and positioned within the passageway in accordance with the rate of flow of fluid through said passageway,
a transparent sight glass tube disposed to the one end of said passageway, a rod connected to the float assembly and extended into the sight glass tube,
an indicating disc connected to the rod within said tube, an elongated housing secured to the lower end of said body and enclosing said sight glass tube and having a visual slot portion exposing a slot like portion of said tube for visual view of the tube,
a rod connected to the float assembly and extended into the sight glass tube,
an indicator connected to the rod within the sight glass tube whereby the position of the indicator within the sight glass tube is proportional to the rate of flow,
said housing having a generally H-shaped cross section with a relatively heavy cross bar including a tube opening telscoped over said tube, said H-shaped housing defining a light chamber to one side of said tube and detector chamber to the opposite side of said tube and having elongated light transmitting slots to the opposite sides of said tube opening,
a mounting board located in said detector chamber,
a plurality of LED diode lamps arranged in alignment with said light chamber and said light transmitting slot in the cross bar adjacent the light chamber and transmitting light through the tube into the detector chamber,
a plurality of phototransistors secured to said mounting board and arranged in alignment with said light transmitting slots,
a shadow mask interposed between said mounting board and said cross bar, said mounting board and said mask being laterally adjustable relative to said light transmitting slot, whereby said phototranasistors are illuminated in accordance with the length of said rod projecting into said sight glass tube,
a multiplexing module having a plurality of inputs connected one to each of said phototransistors and plurality of output and control leads, latch circuit means connected to said multiplexing module for sequentially reading the state of each of said phototransistors, a common input/output line connected to said latch circuit means providing an output signal for each of said lamps in sequence.
a microprocessor having a programmed means,
a coupling circuit coupled to said latch circuit means for reading of said successive signals,
a programmable range selection means connected to said microprocessor and programmed to define an operable range of signals and including a plurality of programming means operable to adjust the input signals to different flow ranges,
an D/A converter connected to said microprocessor and having an anlog signal line and establishing an output signal proportional to the instantaneous level of said flow related signal,
a voltage output signal means connected to said analog signal line to generate an operating voltage signal providing a voltage proportional to the position of said indicator, and
a current drive including a plurality of individual parallel circuits, each of said current drive circuits including a field effect transistor having its main terminals connected in series to the analog signal line and an output stop having an amplifying means connecting the field effect transistor to an output port means to establish a current signal proportional to the position of said indicator to create a current signal proportional to the analog voltage signal.

15 more elements

Dependencies are inferred from the claim text.

Linear digital flowmeter

Life of this patent

Linear digital flowmeter

Life of this patent

Abstract

Claims21