JP2593224Y2 - Impeller type flow detector - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impeller type flow detector for electrically detecting the amount of fluid flowing in a flow path.
It is used for measuring a fuel consumption rate in an internal combustion engine or for measuring a residual fuel in a fuel source.

[0002]

2. Description of the Related Art A conventional impeller type flow detector is disclosed in
No. 22492. According to this, fluid flows in from the inflow hole formed in the housing in the tangential direction of the concave hole of the housing, generates a swirling flow in the concave hole, and rotates the impeller in the concave hole. According to the rotation of the impeller, the light emitted from the light emitting element toward the light receiving element is blocked by a blocking piece erected on the impeller, and this light blocking action is converted into an electric signal to detect the rotation speed of the impeller. Thus, the fluid flow rate is detected. In order to measure the amount of fuel supplied to the engine using such an impeller type flow detector, each device is connected as shown in FIG. 4 to form a fuel supply system. To explain from the upstream side to the downstream side in the fuel flow direction, T is a fuel source in which fuel is stored, F is an impeller type flow detector, P is a fuel pump,
C is a vaporizer and E is an engine. According to the above, when the fuel pump P is driven, the fuel in the fuel source T flows from the inlet of the impeller type flow detector into the recess of the housing, and then is drawn into the fuel pump P from the outlet. And the fuel pump P
The fuel discharged toward the carburetor C from the discharge hole is supplied to the engine E via the carburetor C. In the impeller type flow rate detector, the fuel flow rate is detected according to the flow velocity of the swirling flow flowing in the recess of the housing.

[0003]

In such a fuel supply apparatus, a diaphragm pump is often used as the fuel pump P. This is a pulsating pressure generated in the engine or a mechanical reciprocating motion of the diaphragm to increase or decrease the volume of the pump chamber divided by the diaphragm to suck and discharge the fuel into the pump chamber. Pumps are often employed because their structure is relatively simple and can be manufactured at low cost. As described above, when the diaphragm type fuel pump P is used, the error tends to be deviated in the minus direction in a small flow rate region of the fuel flowing into the recess of the housing from the inlet of the impeller type flow detector. However, improvement in measurement accuracy in a small flow rate region cannot be expected. This means that in a small flow rate range of the fuel flow rate, the time required for one reciprocating operation stroke of the diaphragm of the fuel pump P becomes long, and a large pulsating pressure is generated. (The large pulsating pressure is the absolute pressure difference per cycle.) This pulsating pressure acts in the recess of the impeller type flow detector via the outflow hole, and acts to suppress the rotation force of the rotation of the impeller. That is, in the small flow rate range of the fluid, the impeller performs low rotation by the swirling flow having a small rotating force generated according to the small flow rate. When the pulsating pressure acts, a speed change always occurs with respect to the rotational force of the small swirling flow, which leads to a further decrease in the rotational force, and the rotation of the impeller tends to decrease, so that an error occurs in a small flow rate region. It is thought that it is shifted to a negative trend. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides an impeller-type flow detector capable of improving flow measurement accuracy in a small flow region without increasing pressure loss of the flow detector. is there.

[0004]

According to the present invention, in order to achieve the above object, an impeller is rotatably supported in a recess formed in a housing, and a recess is formed through an inflow hole opened in the recess. The impeller is rotated by a fluid flow that supplies a fluid into the inside and discharges the fluid from an outflow hole that opens into the recess to generate in the recess. In the impeller flow rate detector that detects the flow rate of fluid by electrically detecting the rotation speed of the impeller by this blocking action, the light emitted toward the light receiving element from the The area S1 of the opening is set in a range of 1 to 1.3 times the area S2 of the opening in the recess of the inflow hole.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an impeller type flow detector F according to the present invention will be described below with reference to the drawings. Lower end surface 1 of housing 1
A recess 2 is recessed upward from A, and a locking step 2A is formed at an intermediate position of the recess 2 and the locking step 2 is further formed.
A sensor housing concave portion 2B is formed which is expanded to the side of the concave hole 2 toward the lower end surface 1A from the concave hole 2 located above A. The sensor storage recess 2B is shown in FIG. The upper bottom surface 2C formed above the concave hole 2 is the deepest bottom surface 2D.
And the middle deep bottom surface 2E. The middle deep bottom surface 2E and the deepest bottom surface 2D are connected by a vertical wall surface 2F. The inflow hole 3 opening in the tangential direction of the recess 2 is the right side wall of the recess 2 and opens toward the middle deep bottom surface 2E, while the outflow hole 4 opening in the tangential direction of the recess 2 is It is a vertical wall surface 2F and opens toward the deepest bottom surface 2D. The difference between the depths of the opening positions of the inflow hole 3 and the outflow hole 4 in this way means that the fluid flowing into the recess 2 is
It is performed because it is effective to generate a swirling flow by rotating it by 60 degrees or more. The following components are assembled to the housing 1. Reference numeral 5 denotes a partition plate fixed on the locking step 2A, and an adjusting screw 6 is screwed into the center of the partition plate. Reference numeral 7 denotes an impeller, which is well known, has a shaft 8 at the center thereof, a plurality of blades 10 erected upward from the disk 9, and a plurality of blades 10 on the outer periphery of the disk 9. The blocking pieces 11 are erected downward at equal intervals on the circumference. The impeller 7 is rotatably supported in a recess 2 (hereinafter referred to as a rotating chamber D) above the partition plate 5.
The upper end of the adjusting screw 6 is supported by the bearing 12 at the upper end of the adjusting screw 6. According to this, the impeller 7 is in the rotation chamber D, the blade 10 of the impeller 7 faces the inflow hole 3, and the lower end face of the blocking piece 11 faces the upper end face of the partition plate 5. Reference numeral 14 denotes a sensor, and a light emitting element 15 and a light receiving element 16 are provided on an upper end surface 14B of the sensor supporting portion 14A.
Are erected upward with a gap. The sesan 14 is integrally attached to a cover 17 that closes an opening in the lower end surface 1A of the concave hole 2 of the housing 1.
By closing the opening of the concave hole 2 in the lower end surface 1A with the cover 17, the sensor support portion 14 of the sensor 14 is closed.
A is inserted into the concave hole 2 including the sensor housing recess 2B, and the light emitting element 15 and the light receiving element 16 are inserted into the sensor housing recess 2B.
B is inserted into the rotating chamber D containing the light emitting element 15
The blocking piece 11 of the impeller 7 is inserted and arranged with a gap in a gap between the light receiving element 16 and the light receiving element 16. Since the sensor 14 itself is publicly known, the description of the resistance, the terminal, the lead wire, and the like is omitted. The inlet 3 of the impeller type flow detector F is connected to the fuel source T in FIG. 4, and the outlet 4 is connected to the fuel suction passage P1 of the fuel pump P.
When the fuel pump P is driven, the fuel in the fuel source T flows in the tangential direction of the rotating chamber D from the inflow hole 3 opened in the rotating chamber D of the housing 1, and the fuel turns in the rotating chamber D. A flow is generated, and fuel is sucked from the outlet hole 4 toward the fuel suction passage P1 of the fuel pump P. According to the wing 10 receiving the swirling flow of the fluid in the rotating chamber D,
The impeller 7 disposed in the rotation chamber D rotates, and according to the rotation of the blocking piece 11 due to the rotation of the impeller 7, the light beam emitted from the light emitting element 15 toward the light receiving element 16 is blocked. The blocking action is converted into an electric signal to detect the rotation speed of the impeller 7 and thus the flow rate of the fluid.

Here, the inventor of the present application reduces the opening area S1 of the outflow hole 4 into the concave hole 2 so that the pulsating pressure generated in the fuel pump P causes the rotation chamber D of the impeller type flow detector to rotate.
The impeller-type flow rate detector F is improved by reducing the influence on the inside and thereby reducing the error of the negative tendency especially in the low flow rate region, and by reducing the opening area S1.
It was confirmed that the pressure loss of the fuel pump P became large and the pump capacity of the fuel pump P needed to be increased. In order to improve the negative error in the low flow rate region without increasing the pump capacity of the fuel pump P, the opening area S2 of the inflow hole 3 and the opening area of the outflow hole 4 opened in the concave hole 2. It is noted that this is achieved by setting S1 appropriately. The tests were performed on the following samples. In this case, in each sample, the diameter of the suction hole 3 was fixed at 5.2 mm, and in this state, the diameter of the outflow hole 4 was changed to change S1 / S2. The test results as described above are shown in FIG. According to this, in sample 1, the opening area S1 of the outflow hole 4 is the smallest diameter (4.65 mm) and S1 / S2 is as small as 0.8, so that the pulsating pressure generated in the fuel pump P is reduced by the impeller type. Although it is difficult for the flow rate to be transmitted to the inside of the rotation chamber D of the flow rate detector F and the error in the negative tendency in the low flow rate area can be remarkably improved, the pressure loss increases due to the small diameter of the outflow hole 4 and the pump capacity of the fuel pump P increases. And has a disadvantage that it cannot be put to practical use. Further, in the sample 3, the opening area S1 of the outflow hole 4 is the largest diameter (6.37 mm).
Since / S2 is 1.5, the pressure loss in the impeller type flow rate detector F does not increase and the pump capacity of the fuel pump P can be reduced, but the fuel pump in the low flow rate range The pulsating pressure generated in P greatly affects the inside of the rotating chamber D, so that the error of the minus tendency in the low flow rate region cannot be improved. On the other hand, according to Sample 2, the opening area S1 of the outflow hole 4 is a medium diameter (5.58 mm) and S1 / S2 is 1.15,
The influence of the pulsating pressure generated in the fuel pump P on the rotating chamber D can be reduced, the error of the negative tendency in the low flow rate region can be improved, and the fuel pump P
The conventional fuel pump can be used as it is without changing the pump capacity. And S1 / S2
Was in the range of 1.0 to 1.3, it was confirmed that substantially the same effect as that of Sample 2 was obtained.

[0007]

As described above, according to the present invention, the pressure loss is relatively small, and the error of the negative tendency in the low flow rate region can be improved without increasing the pump capacity of the conventional fuel pump. The practical effect is great.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of an impeller type flow detector according to the present invention.

FIG. 2 is a longitudinal sectional view taken along line RR of FIG. 1;

FIG. 3 is a transverse sectional view taken along line QQ in FIG. 1;

FIG. 4 is a system diagram showing a fuel supply system in which an impeller type flow detector is used.

FIG. 5 is a diagram showing a relationship between a fluid flow rate and an error of an impeller flow rate detector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Concave hole D Rotating chamber 3 Inlet hole 4 Outlet hole 7 Impeller P Fuel pump P1 Fuel suction path T Fuel source

Claims (1)

(57) [Scope of request for utility model registration] An impeller is rotatably supported in a recess formed in a housing, and fluid is supplied from an inflow hole opened in the recess to the recess and an outflow hole opened in the recess. The impeller is rotated by a fluid flow generated in the concave hole by discharging the fluid, and a light beam emitted from the light emitting element toward the light receiving element is blocked by a blocking piece provided on the impeller. In the impeller type flow rate detector, which electrically detects the rotational speed of the impeller to detect the flow rate of the fluid, the outflow hole 4 is connected to the fuel suction passage P1 of the fuel pump P, and the inflow hole 3 is connected to the fuel source T And the recess 2 of the outflow hole 4
An impeller type flow detector characterized in that a hole area S1 opening into the inside is set in a range of 1 to 1.3 times a hole area S2 opening into the concave hole 2 of the inflow hole 3.