阅读说明：本技术 弹性负载式金属管浮子流量计 (Elastic load type metal tube float flowmeter ) 是由 刘文凤 于闰成 顾丽娜 田野 于 2020-07-07 设计创作，主要内容包括：本发明弹性负载式金属管浮子流量计,其特征是传感器由测量管、圆形孔板、浮子组件、导杆、导杆前端支架、导杆后端支架、浮子弹簧构成；浮子组件由类锥形浮子、磁钢套、导套构成；导套的前部与类锥形浮子的中心孔固定配合连接,导套的前部内孔与导杆滑动配合,在导杆后端支架的前端设有浮子弹簧座套,浮子弹簧座套的前部与类锥形浮子的导套的内孔滑动配合,浮子弹簧安装在浮子弹簧座套上对类锥形浮子实施弹簧压力作用；所述的类锥形浮子的截面为在轴向等间距设点、半径由大至小变化的拟合曲线形。其流量输出的刻度显示跨度均匀,检测精度可达±1%FS,压力损失小,便于装卸维修。(The invention relates to an elastic load type metal tube float flowmeter, which is characterized in that a sensor consists of a measuring tube, a circular orifice plate, a float assembly, a guide rod front end bracket, a guide rod rear end bracket and a float spring; the floater component consists of a cone-like floater, a magnetic steel sleeve and a guide sleeve; the front part of the guide sleeve is fixedly matched and connected with a center hole of the similar conical floater, an inner hole at the front part of the guide sleeve is in sliding fit with the guide rod, a floater spring seat sleeve is arranged at the front end of the support at the rear end of the guide rod, the front part of the floater spring seat sleeve is in sliding fit with the inner hole of the guide sleeve of the similar conical floater, and the floater spring is arranged on the floater spring seat sleeve and exerts spring pressure action on the similar conical floater; the section of the cone-like floater is a fitting curve shape with points arranged at equal intervals in the axial direction and with the radius changing from large to small. The scale display span of the flow output is uniform, the detection precision can reach +/-1% FS, the pressure loss is small, and the loading, unloading and maintenance are convenient.)

1. An elastic load type metal tube float flowmeter is composed of a sensor and a converter,

the sensor is characterized by comprising a measuring pipe, a circular orifice plate, a floater component, a guide rod front end bracket, a guide rod rear end bracket and a floater spring;

the front end and the rear end of the measuring pipe are respectively provided with a measuring pipe front end flange and a measuring pipe rear end flange;

the front end bracket of the guide rod is fixedly arranged in the inner hole of the front end flange of the measuring tube, the rear end bracket of the guide rod is fixedly arranged in the inner hole of the rear end flange of the measuring tube, the front end of the guide rod is fixedly connected with the center of the front end bracket of the guide rod, and the rear end of the guide rod is in positioning fit connection with the center of the rear end bracket of the guide rod;

the floater component consists of a cone-like floater, a magnetic steel sleeve and a guide sleeve; the magnetic steel sleeve is arranged in a spigot groove of a central hole of the similar conical floater, the front part of the guide sleeve is fixedly matched and connected with the central hole of the similar conical floater, and an inner hole at the front part of the guide sleeve is in sliding fit with the guide rod; the rear part of the guide sleeve extends out of the rear end of the cone-like floater;

the front end of the guide rod rear end support is provided with a float spring seat sleeve, the front part of the float spring seat sleeve is in sliding fit with an inner hole of the guide sleeve of the similar conical floater, a cylindrical floater spring is arranged on the float spring seat sleeve of the guide rod rear end support, and the cylindrical floater spring pushes the rear end of the guide sleeve of the similar conical floater to apply spring pressure action on the similar conical floater; a circular pore plate is fixedly arranged in the measuring tube corresponding to the similar conical floater;

the section of the cone-like floater is a fitting curve shape with points arranged at equal intervals in the axial direction and with the radius changing from large to small;

when the cone-like floater is at the maximum flow position, namely the maximum compression amount Xmax of the floater spring, the maximum elastic force F of the floater spring is equal to the difference value between the gravity and the buoyancy of the floater in the vertically-installed metal tube floater flowmeter, namely the maximum elastic force F of the floater spring is equal to the thrust of the cone-like floater corresponding to the fluid at the maximum flow;

F=K·X_max= gravity-buoyancy

F is the elastic force of the float spring, kgf

X_maxMaximum compression of float spring,mm

K is the elastic coefficient (kgf/mm) of the float spring;

when the cone-like float is in the zero position, the spring force of the float spring is preferably set to 0.12 times the maximum spring force of the float spring.

2. The spring-loaded metal tube float flowmeter of claim 1, wherein:

a plurality of axial elongated drainage slotted holes (33) are distributed on the rear part (32') of the guide sleeve extending out of the rear end of the similar conical floater;

a plurality of axial elongated slotted holes (611) are distributed on the float spring seat sleeve (61);

a boss (612) is arranged at the front end of the float spring seat sleeve (61), and the boss (612) is in sliding fit with an inner hole at the rear part (32 ') of the guide sleeve so as to reduce the sliding fit surface of the float spring seat sleeve (61) and the inner hole at the rear part (32') of the guide sleeve.

Technical Field

The invention relates to a metal tube float flowmeter.

Background

The metal tube float flowmeter is a pipeline flow measuring instrument, and the installation mode is divided into a vertical mode and a horizontal mode.

The present metal tube float flowmeter installed horizontally consists of two parts, sensor and converter. The sensor part comprises an input pipe, an output pipe, a vertical pipe, a measuring pipe, a conical floater, a floater lower limiting ring, a floater upper limiting ring and a pore plate, wherein the input pipe and the output pipe are arranged at the left side and the right side of the lower end of the vertical pipe, the upper end of the measuring pipe is fixedly connected with the upper end of the vertical pipe through a flange plate, the lower end of the measuring pipe is communicated with the input pipe, the upper end of the measuring pipe is provided with a discharge hole, the floater lower limiting ring and the floater upper limiting ring are respectively and fixedly arranged at the upper end and the lower end of the measuring pipe, guide rods at the upper end and the lower end of the conical floater are respectively in sliding fit.

The working principle is that a medium enters the measuring pipe from the input pipe and flows upwards, the conical floater is acted by upward lifting force, buoyancy force and downward gravity, when the three forces are balanced, the conical floater stays at a certain position, the conical floater and the pore plate form an annular gap flow surface, the annular gap flow surface and the passing flow are in a certain corresponding relation, and the flow is large when the area of the annular gap flow surface is large. The magnetic steel in the conical floater is coupled with the magnetic steel on the rotating shaft in the converter, the magnetic steel is converted into a flow value through the converter, and a pointer dial is used for indicating or outputting a 4-20 mA current signal.

The horizontal metal tube float flowmeter in the prior art is a deformation of a vertical structure, although media are fed in and discharged out of a horizontal tube, a measuring part is still in the vertical structure, fluid enters the measuring tube to be baffled by 90 degrees, so that the fluid generates turbulent flow, namely, bias flow and rotational flow, the flow field of the lower part of a conical float and the annular gap flow surface of a pore plate is distorted, the conical float is seriously shaken, the matching with a converter is influenced, the measuring precision of the metal tube float flowmeter is reduced, and the detection precision is greater than +/-1.5% FS.

The flow area between the conical floater and the orifice plate of the metal pipe floater flowmeter in the prior art is in corresponding relation with the flow, but the scale display span of the flow output is large in change, particularly, the scale span is small when 50% -100% of the flow is output, namely, the display scale is dense, so that the scale display is uneven, and the visual effect is poor.

In addition, the sensor of the metal pipe float flowmeter installed on the pipeline is a resistance element, pressure loss is generated when the fluid passes through the sensor of the metal pipe float flowmeter, certain pipeline pressure loss is caused, the smaller the pipeline pressure loss is better in production, and the continuous baffling of the fluid in the prior art can cause larger pressure loss.

Disclosure of Invention

The invention aims to improve the defects of the prior art and provides a horizontal metal tube float flowmeter which has high detection precision, small pressure loss, uniform scale display distribution, reliable work and convenient installation, use and maintenance.

The invention relates to an elastic load type metal tube float flowmeter, which consists of a sensor and a converter;

the sensor comprises a measuring tube, a round orifice plate, a floater component, a guide rod front end bracket, a guide rod rear end bracket and a floater spring.

The front end and the rear end of the measuring pipe are respectively provided with a measuring pipe front end flange and a measuring pipe rear end flange.

The guide rod front end bracket is fixedly arranged in an inner hole of a measuring pipe front end flange, the guide rod rear end bracket is fixedly arranged in an inner hole of a measuring pipe rear end flange, the guide rod front end is fixedly connected with the guide rod front end bracket center, and the guide rod rear end is connected with the guide rod rear end bracket center in a positioning matching manner.

The floater component consists of a cone-like floater, a magnetic steel sleeve and a guide sleeve; the magnetic steel sleeve is arranged in a spigot groove of a central hole of the similar conical floater, the front part of the guide sleeve is fixedly matched and connected with the central hole of the similar conical floater, and an inner hole at the front part of the guide sleeve is in sliding fit with the guide rod; the rear part of the guide sleeve extends out of the rear end of the cone-like floater.

The front end of the guide rod rear end support is provided with a float spring seat sleeve, the front part of the float spring seat sleeve is in sliding fit with an inner hole of the guide sleeve of the similar conical floater, a cylindrical floater spring is arranged on the float spring seat sleeve of the guide rod rear end support, and the cylindrical floater spring pushes the rear end of the guide sleeve of the similar conical floater to apply spring pressure action on the similar conical floater; and a circular orifice plate is fixedly arranged in the measuring tube corresponding to the similar conical floater.

The section of the cone-like floater is a fitting curve shape with points arranged at equal intervals in the axial direction and with the radius changing from large to small.

The invention relates to a sensor working principle of an elastic load type metal tube float flowmeter, which comprises the following steps:

when fluid in the measuring pipe flows, the similar conical floater is pushed to move axially, an annular gap flow surface is formed between the similar conical floater and the circular pore plate, pressure difference between the front end and the rear end of the similar conical floater is formed, the cylindrical floater spring acts on the rear end of the similar conical floater, the pressure of the front end and the rear end of the similar conical floater is balanced, and the similar conical floater stays at a certain position.

The circulation area delta F is the annular gap circulation surface formed by the outer diameter of the cone-like floater and the inner diameter of the circular orifice plate

The following is obtained according to Bernoulli's equation and continuity equation: volume flow rate Q_VThe following relationship is associated with flow area △ F:

wherein:

Q_V: flow value of each flow point of float

α: flow coefficient of meter

: =1 when the fluid to be measured is liquid, and the gas expansion coefficient when the fluid to be measured is gas, which is normally ignored because the correction amount of this coefficient is small, and which can be included in the flow coefficient of the meter by verification

Delta F: flow area

g: acceleration of gravity, m/s²

G_f: mass of float, kg

V_f: volume of float and fruit of bear Ding

ρ: measured fluid density, kg/m

F_f: the cross-sectional area of the maximum radius of the floater is square meter.

Round orifice plate and float of sensorWhen the structure and the measured fluid are timed, α, G and G in the formula (1)_f、V_f、ρ、F_fThese parameters are determined and can be considered as a constant C during operation, namely:

the formula (1) is changed into an integration formula:

q in formula (3)_VAnd △ F are in direct proportional correspondence, this configuration allows for measurement of fluid flow in the pipe.

r₀Maximum radius of float (corresponding to zero position)

r_nFor the radius of each flow point of the float (n is the flow set point: 0, 1, 2, 3 … … 8, 9, 10)

It can be known from the formula (3) that the flow rate is only related to the annular gap flow area between the cone-like float and the orifice plate, and is not related to the spring force of the float spring. The main function of the float spring is to return the cone-like float when the flow is small.

The parametric design of the float spring was analyzed with reference to the force of the float in a vertically mounted metal tube float flowmeter:

when the cone-like floater is at the maximum flow position, namely the maximum compression amount Xmax of the floater spring, the maximum elastic force F of the floater spring is equal to the difference value between the gravity and the buoyancy of the floater in the vertically-installed metal tube floater flowmeter, namely the maximum elastic force F of the floater spring is equal to the thrust of the cone-like floater corresponding to the fluid at the maximum flow;

F=K·X_max= gravity-buoyancy … … … … (5)

F is the elastic force of the float spring, kgf

X_maxFloating foodMaximum compression of the sub-spring, mm

K is the elastic coefficient (kgf/mm) of the float spring.

In order to ensure that the flow is zero, the float spring pushes the cone-like float back to the zero position, and when the cone-like float is in the zero position, the float spring keeps certain elastic force.

Table 1: steel-steel friction coefficient:

as can be seen from the above table, when the cone-like float is at the zero position, the elastic force of the float spring is preferably set to be 0.12 times the maximum elastic force of the float spring, so as to overcome the friction force between the cone-like float and the guide rod and push the cone-like float back to the zero position.

When no medium flows in the measuring pipe, the clearance between the maximum end of the cone-like floater and the circular hole plate is about 0.2mm, namely the zero point position. When a medium flows in the measuring pipe, the medium flows to push the cone-like floater to move axially to compress the cylindrical floater spring, the gap between the circular pore plate and the cone-like floater is enlarged, the flow area is enlarged, and when the minimum end of the cone-like floater corresponds to the circular pore plate, the flow is maximum.

According to the requirements of the JJG 257-2007 float flowmeter verification regulations, the appearance design of the cone-like float is a fitting curve with points arranged at equal intervals in the axial direction 10 equal parts and with the radius changing from large to small. The flow setting points correspond to the equal-interval points of 10 equal parts in the axial direction of the cone-like floater one by one, and each setting point corresponds to a scale value on the dial, so that the flow indicating values on the dial are distributed in a uniform state, and the reading of the values is facilitated.

The flow area between the similar conical floater of the metal tube floater flowmeter and the circular orifice plate is in corresponding relation with the flow, the circular magnetic steel sleeve arranged in the similar conical floater is coupled with the magnetic steel in the converter and is indicated by the pointer and the dial, the scale display span of the flow output is uniform, the visual effect is good, the detection precision is high, and the detection precision can reach +/-1% FS. And the medium does not have 90 degrees baffling, so that the fluid generates turbulent flow, the floater has good stability and small pressure loss, and the maintenance, the assembly and the disassembly of the floater are convenient.

Drawings

Fig. 1 is a schematic diagram of a prior art horizontal metal tube float flow meter.

Fig. 2 and 3 are schematic structural diagrams of an embodiment of the present invention, wherein fig. 2 is a state when the flow rate is zero, and fig. 3 is a state when the flow rate is close to the maximum.

Fig. 4 is a schematic structural view of an embodiment of a guide sleeve with a cone-like floating structure.

FIG. 5 is a schematic structural view of an embodiment of a guide rod rear end bracket.

FIG. 6 is a schematic view of the structure state of a cone-like floater, and a cross-section fitting curve is that points are set at equal intervals in the axial direction and the radius changes from large to small.

Detailed Description

The invention relates to an elastic load type metal tube float flowmeter, which consists of a sensor and a converter; the sensor comprises a measuring tube 1, a round orifice plate 2, a floater component 3, a guide rod 4, a guide rod front end bracket 5, a guide rod rear end bracket 6 and a floater spring 7.

The front end of the measuring pipe 1 is welded with a measuring pipe front end flange 11, and the rear end of the measuring pipe 1 is welded with a measuring pipe rear end flange 12.

The guide rod front end bracket 5 is fixedly arranged in an inner hole of a measuring pipe front end flange 11 through a spigot and a clamp spring 51, the guide rod rear end bracket 6 is fixedly arranged in an inner hole of a measuring pipe rear end flange 12 in a welding mode, the front end of the guide rod 4 is fixedly connected with a center hole of the guide rod front end bracket 5 in a matched mode through a threaded end and a locking nut 41, and the rear end of the guide rod 4 is matched with a center hole of the guide rod rear end bracket 6 in a plug-in locating mode.

The floater component 3 consists of a cone-like floater 30, a magnetic steel sleeve 31 and a guide sleeve 32; the magnetic steel sleeve 31 is fixedly arranged in a slot of a spigot of a central hole of the similar conical floater 30, the front part of the guide sleeve 32 is matched, welded and fixedly connected with the spigot of the central hole of the similar conical floater, and the front part of an inner hole of the guide sleeve 32 is in sliding fit with the guide rod 4; the rear of the guide sleeve 32 extends beyond the rear end of the cone-like float 30.

A float spring seat sleeve 61 is integrally or fixedly connected with the front end of the guide rod rear end support 6, the float spring seat sleeve 61 is in sliding fit with the rear part of the inner hole of the guide sleeve 32, the cylindrical float spring 7 is arranged on the float spring seat sleeve 61 of the guide rod rear end support, and the high-precision stainless steel cylindrical float spring 7 pushes the rear end of the guide sleeve 32 to apply axial spring pressure to the similar conical float 30; the corresponding cone-like floater 30 is fixedly provided with a round orifice plate 2 in the measuring tube.

The section of the cone-like floater is a fitting curve shape with points arranged at equal intervals in the axial direction and with the radius changing from large to small.

In the embodiment shown in fig. 4, a plurality of axial elongated drainage slots 33 are distributed on the rear part 32' of the guide sleeve extending out of the rear end of the similar conical floater 30, which prevent dirt from being deposited in the inner hole of the guide sleeve 32 and block the similar conical floater 30 from axially sliding.

As shown in fig. 5, a plurality of axial elongated slots 611 are distributed on the float spring seat sleeve 61, and are used for preventing dirt from attaching to the surface of the float spring seat sleeve 61 to retard the telescopic motion of the float spring 7, reducing the contact area between the float spring 7 and the float spring seat sleeve 61, and reducing the sliding resistance; the front end of the float spring seat sleeve 61 is provided with a boss 612, and the boss 612 is in sliding fit with the inner hole of the rear part 32 'of the guide sleeve so as to reduce the sliding fit surface between the float spring seat sleeve 61 and the inner hole of the rear part 32' of the guide sleeve, so that the sliding fit is easier.