JPH0210312B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is a constant flow valve configured to automatically maintain a constant fluid flow rate regardless of pressure fluctuations by being installed in a water supply system such as a water heater.
Specifically, there is a piston that slides along the fluid flow direction in response to fluctuations in the differential pressure between the primary pressure and the secondary pressure, and a fluid communication portion formed between the piston and the piston due to the sliding movement of the piston. The present invention relates to a constant flow valve having a needle that automatically changes the area so that the area becomes narrower as the differential pressure increases. Conventional constant flow valves have only one flow rate control section, the needle working with the piston to maintain a constant flow rate; however, when using this, when changing the flow rate ,
It may be necessary to replace the needle with one equipped with the necessary flow control unit, or to replace the entire valve.
It was difficult to change the flow rate on the user side. In view of the above-mentioned circumstances, an object of the present invention is to make it possible to change the set flow rate easily, quickly, and accurately. In the constant flow valve according to the present invention, a large flow rate control part and a small flow rate control part are arranged in the needle in the axial direction, and the large and small flow rate control part selectively controls the needle with respect to the piston. It is characterized by being provided with a mechanism for changing and fixing the position so as to function. That is, the needle is equipped with two types of flow rate control parts, a large flow rate control part and a small flow rate control part, and the flow rate can be switched by selectively operating both flow rate control parts. Therefore, according to the present invention, the needle can be replaced on the user's side without requiring labor-intensive work such as needle replacement or valve replacement that requires disassembling and assembling the valve, and requiring specialized knowledge. The set flow rate can be easily and quickly changed by a simple external operation such as changing the position in the fluid flow direction. Moreover, both the flow rate control parts of the needle are dedicated to each large and small flow rate control part, and both flow rate control parts act on the piston by changing the position between two positions in the axial direction of the needle, so accurate control can be achieved. Flow rate changes can be made. An object of the second invention is to reduce the operating force when changing the position of the needle by holding it against the fluid flow. An improvement of the second invention over the first invention is that the piston member is provided with a piston member that applies a moving force to the needle in a direction opposite to the fluid flow direction by using a pressure difference between the primary pressure and the secondary pressure. It is located at the point connected to the needle. Therefore, according to the second invention, when changing the position of the needle against the fluid flow, the needle movement resistance due to the fluid flow can be offset or reduced by the movement force due to the differential pressure, so that the needle movement operation force is reduced. Therefore, when changing the position of the needle using an actuator, it is possible to use a small solenoid or the like as the actuator, and it can be implemented at low cost. Moreover,
Since the piston member is simply provided on the needle, the structure is simple and easy to manufacture. Embodiments of the present invention will be described below based on the drawings. 1 is a piston provided in a fluid flow path 3 formed in a case 2 so as to be able to slide freely along the fluid flow direction; 4 is a piston that allows the piston 1 to maintain the differential pressure between the primary pressure and the secondary pressure; A control spring 5 biases the piston 1 toward the upstream side so as to slide in response to fluctuations, and 5 indicates a fluid flow formed between the piston 1 and the piston 1 by the sliding movement of the piston 1. This is a needle that automatically changes the area of the passage 6 so that it becomes narrower as the differential pressure increases, and as shown by line _A in FIG. Q, flow rate Q
large flow rate control unit 5 for maintaining the large flow rate _Q1
A and the primary pressure P ₁ as shown by the line B in Figure 3.
A small flow rate control section 5B for maintaining the flow rate Q at a small flow rate _Q2 regardless of fluctuations in the flow rate is formed side by side in the axial direction. 7 is energized to move the large flow rate control part 5A from the axial position where it acts on the piston 1 to the upstream axial position where the small flow rate control part 5B acts on the piston 1 due to the biasing force of the spring 8. 9 is a solenoid whose position is changed and fixed while resisting, and 9 is a position where the small flow rate control section 5B acts on the piston 1 by receiving the spring 8 and coming into contact with the case 2 when the solenoid 7 is energized. 10 is a stopper which, by contacting the case 2, prevents the needle 5 from moving downstream from the position where the large flow rate control section 5A acts on the piston 1. be. Reference numeral 11 denotes a cylinder chamber formed in a posture along the axial direction in a portion of the case 2 facing the upstream end of the needle 5 in the axial direction, and this cylinder chamber has an open communication with the primary pressure chamber 12 at one end. However, the other end communicates with a secondary pressure chamber 14 via a pressure guiding passage 13. Reference numeral 15 denotes a piston member fitted in the cylinder chamber 11 so as to be movable in the axial direction. It is integrally connected to the needle 5 so as to apply it to the needle 5. The diameter of the piston member 15 is arbitrary as long as the spring constant of the spring 8 and the mounting load are selected. The following table shows the resistance at each water pressure value when moving the needle 5 to the upstream side in cases where the piston member 15 is provided as in the above embodiment, and when the piston member 15 is not provided. In addition, piston member 1
The diameter of portion 5 is the same as the diameter of portion 5C located between both control portions 5A and 5B.

[Table] The position change fixing mechanism 7 may be a manually operated lever.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional view showing the state during large flow control;
FIG. 2 is a longitudinal sectional view showing the state during small flow rate control, and FIG. 3 is a graph showing the flow rate control characteristics. 1... Piston, 5... Needle, 5A... Large flow control section, 5B... Small flow control section, 7...
Position change fixing mechanism, 15... Piston member.

Claims (1)

[Claims] 1. A piston 1 that slides along the fluid flow direction in response to fluctuations in differential pressure between primary pressure and secondary pressure.
and a needle 5 that automatically changes the area of the fluid circulation portion 6 formed between the piston 1 and the piston 1 by sliding the piston 1 in such a manner that the area becomes narrower as the differential pressure increases. , a large flow rate control section 5A and a small flow rate control section 5B are formed side by side in the axial direction on the needle 5, and
The needle 5 is connected to the large/small flow rate controllers 5A, 5.
A constant flow valve characterized in that a mechanism 7 for changing and fixing the position of B so as to selectively act on the piston 1 is provided. 2 Piston 1 that slides along the fluid flow direction in response to differential pressure fluctuations between primary pressure and secondary pressure
and a needle 5 that automatically changes the area of the fluid circulation portion 6 formed between the piston 1 and the piston 1 by sliding the piston 1 in such a manner that the area becomes narrower as the differential pressure increases. , a large flow rate control section 5A and a small flow rate control section 5B are formed side by side in the axial direction on the needle 5, and
The needle 5 is connected to the large/small flow rate controllers 5A, 5.
A mechanism 7 is provided for changing and fixing the position of B so as to selectively act on the piston 1, and the needle 5 is provided with a mechanism 7 for changing and fixing the position so that B acts selectively on the piston 1, and the needle 5 is provided with a mechanism 7 that changes the position of the needle 5 by using a pressure difference between the primary pressure and the secondary pressure to adjust the fluid flow direction. A constant flow valve characterized in that a piston member 15 is connected to the needle 5 to apply a moving force in the opposite direction. 3. The constant flow valve according to claim 2, wherein the position change fixing mechanism 7 is a solenoid.