Patent Application
20110100487
This application claims priority of Chinese Patent Application No. 200910208966.3, filed on Nov. 1, 2009, entitled “Flow Path Switch Control Device”, which is incorporated by reference herein.
The present invention relates to a fluid control field, in particular, to a switch device in a control system such as HVAC (heating, ventilating and air conditioning), refrigeration system, etc., and specifically to a flow path switch control device suitable for large capacity and high pressure environment.
A solenoid switch is often used in a temperature controlling and regulating system such as HVAC, refrigeration system, etc. The main principle of the solenoid switch lies in that the up or down movement of an iron core is controlled through an electromagnetic force generated by a energized coil, so as to open or close a solenoid valve in an air conditioning system, thereby controlling on/off of the medium in a pipeline system. As individual housing area becomes larger and buildings such as shopping malls are increased, demand for large capacity air conditioning unit is increased. In such large capacity air conditioning unit, it is required that the solenoid switch should also be of large capacity and large diameter. A conventional direct-operated solenoid valve can not meet the requirement of such working conditions due to limited diameter of the valve. Mostly, a pilot-operated solenoid switch is used to replace the direct-operated solenoid valve. However, since the pressure at an upper portion of a piston will drop instantaneously to the pressure at an outlet at the moment when a pilot valve is opened, a large pressure difference is formed between the upper and lower sides of a piston to drive the piston to move, which results in a strong impact between a piston stopping member and the piston. The impact will be stronger in the valve having larger pressure difference and larger valve diameter. Therefore, there is a problem that the start up of the large capacity pilot solenoid valve in the prior art is not stable.
Accordingly, a large diameter pilot solenoid switch is disclosed in the applicant's Chinese patent No. CN2753926Y published on Jan. 25, 2006. Referring to
In the above solenoid valve configuration, a boss is provided either on the end cover 11 or inside the piston 10 in order to avoid a direct impact between the end surface of the piston 10 and the end cover 11. However, since the pressure difference between the opposite sides of the piston 10 is changed instantaneously at the time of starting up of the valve, such configuration can not thoroughly solve the impact problem, which will affect the life span of the valve and the operating stability of the system.
The technical problem to be solved by the present invention is to control and reduce the pressure change in fluid passing through a valve device by improving the configuration of a conventional large diameter solenoid switch in a refrigeration system. Specifically, during opening of the valve, the fluid flow area in a pressure balancing control circuit is slowly increased such that the pressure difference between the opposite sides of a valve body is increased gradually. Therefore, the opening of the valve is smooth without strong impact and vibration, and thus the problem of strong vibration and noise occurred at the moment when the solenoid switch is operated under large pressure difference is avoided. For this purpose, the present invention provides a flow path switch control device.
The flow path switch control device includes a fluid inlet, a fluid outlet, a valve device arranged between the fluid inlet and the fluid outlet, and a pressure balancing control circuit, wherein an adjusting device is provided in the pressure balancing control circuit to reduce a pressure change in fluid passing through the pressure balancing control circuit when the flow path switch control device is opened/closed.
Specifically, the adjusting device reduces the pressure change in the fluid in the circuit by changing the flow area of the fluid.
Specifically, the adjusting device of the flow path switch control device is driven by a pulse signal.
Further, a pressure balancing hole is further provided in the pressure balancing control circuit. There may be two or more pressure balancing holes. Further, the flow path switch control device also includes a casing which receives the valve device and the adjusting device. A connecting passage communicating the valve device with the adjusting device is provided in the casing.
Further, the valve device and the adjusting device are communicated via a connecting pipe.
The flow path switch control device of the present invention is provided with an adjusting device in the pressure balancing control circuit. The adjusting device is actuated and driven by an external pulse signal to change the flow area of the fluid in the pressure balancing control circuit, and to gradually release the fluid pressure in the pressure balancing control circuit. The flow path switch control device closes the flow path in a full-closed area. The flow path switch control device allows the flowrate to increase slowly and thus open the main vale, or to decrease slowly and thus close the main valve in a flowrate changing area. The flow path switch control device maintain stable open of the mail valve in a full-opened area. In this way, it is smooth during opening and closing of the valve, and thus the problem of strong vibration and noise occurred at the moment when the solenoid switch is operated under large pressure difference is avoided.
In order that those skilled in the art can better understand the technical solutions of the present invention, the opening process of the flow path switch control device will be explained in detail below with reference to the drawings and embodiments.
As shown in
The valve device 103 is wholly disposed in a first receiving chamber 161 of the casing 106. The valve device 103 mainly comprises a valve body 131 and a support member 132. The valve body 131 is slidable within the first receiving chamber 161 and partitions a closed balancing chamber 137 from the first receiving chamber 161. The support member 132 is welded on the casing 16 and seals the first receiving chamber 161. The first receiving chamber 161 is communicated with the inlet chamber 111 via a pressure balancing hole 134 machined in the valve body 131. The balancing hole 134 has a diameter ranged from 0.3 to 1.5 mm, and preferably from 0.5 to 1 mm. The inner cross sectional area of the balancing hole 134 may be set as the flow area S3 of the balancing hole 134. In this embodiment, only one balancing hole 134 is machined in the valve body 131. Certainly, two balancing holes may also be symmetrically machined in the valve body. A seal member 135 made of non-metal material is mounted at the leading end of the valve body 131. A spring 133 is disposed between the valve body 131 and the support member 132 to urge the seal member 135 of the valve body 131 against a first valve port 163 of the casing 106. The flow area of the fluid flowed between the seal member 135 of the valve body 131 and the first valve port 163 of the casing 106 may be set as S1. The flow path between the inlet chamber 111 and the outlet chamber 121 is shut off when the seal member 135 seals against the first valve port 163.
The adjusting device 105 is mounted in a second receiving chamber 162 of the casing 106 by seal welding. The adjusting device 105 mainly comprises an adjusting rod 151, a magnetic rotor 152, a coil 153 and a signal lead wire 107. The adjusting rod 151 is coupled to the magnetic rotor 152 by a transmission pair of a nut 154 and a screw rod 155. The adjusting rod 151 is extended deeply into the second receiving chamber 162. Thus, a pressure balancing control circuit 104 consisted of the first receiving chamber 161, the pressure balancing hole 134, the balancing chamber 137, a connecting passage 141 and the second receiving chamber 162 is formed between the valve device 103 and the adjusting device 105. The flow area of the fluid flowed between the adjusting rod 151 and a second valve port 164 may be set as the flow area S2 of the pressure balancing control circuit 104.
When a certain amount of pulse signal is inputted from the signal lead wire 107, the magnetic rotor 152 is rotated by a certain angle under the action of the coil 153. Then, being driven by the transmission pair of the nut 154 and the screw rod 155, the adjusting rod 151 is moved upwardly or downwardly by a certain displacement within the second receiving chamber 162, so as to change the flow area S2 of the pressure balancing control circuit 104 and thus control the pressure change in the fluid.
Valve opening characteristics in the flow path of the above flow path switch control device is shown in
When the flow path switch control device 100 is in a closed state (position A0), the pressure balancing control circuit 104 is closed, the inlet chamber 111 and the balancing chamber 137 are in a pressure balanced state. That is, ΔF=F1−F2=0, and the valve body 131 abuts against the first valve port 163 under the force F3 of the spring 133.
When the flow path switch control device is started up from the closed state, by inputting a certain amount of pulse signal, the adjusting rod 151 is moved slowly away from the second valve port 164 of the casing 106 and thus the fluid flow area S2 of the pressure balancing control circuit 104 is slowly increased. When this process proceeds to position A1, S2 is equal to the flow area S3 of the pressure balancing hole 134. After S2>S3, the pressure F2 in the pressure balancing control circuit 104 starts to decrease (that is, F1>F2), and thus a pressure difference occurs between the inlet chamber 111 and the balancing chamber 137. When this process proceeds to position A2, F1=F2+F3. After F1>F2+F3, the valve body 131 starts to move away from the first valve port 163 and thus the valve device 131 is opened until it is fully opened in a stable state (i.e., state A3). Thereafter, the flowrate of the valve device becomes stable (i.e., state A4). The above-mentioned valve opening process is smoothly progressed. Therefore, the valve body 131 is prevented from being drastically moved and from impacting with the support member 132.
A valve device 103 is wholly disposed in a first receiving chamber 161 of the valve device housing 136. The valve device 103 mainly comprises a valve body 131 and a support member 132. The valve body 131 is slidable within the first receiving chamber 161 and partitions a closed balancing chamber 137 from the first receiving chamber 161. The support member 132 is welded on the valve device housing 136 and seals the first receiving chamber 161. The first receiving chamber 161 is communicated with the inlet chamber 111 via the pressure balancing hole 134 machined in the valve body 131. The seal member 135 is mounted at the leading end of the valve body 131. The spring 133 is disposed between the valve body 131 and the support member 132 to urge the seal member 135 of the valve body 131 against the first valve port 163 of the valve device housing 136, so as to shut off the flow path between the inlet chamber 111 and the outlet chamber 121.
The adjusting device 105 is connected to the valve device housing 136 and an outlet pipe 122 via connecting pipes 108 and 109, respectively. The adjusting device 105 mainly comprises the adjusting rod 151, the magnetic rotor 152, the coil 153 and the signal lead wire 107. The adjusting rod 151 is coupled to the magnetic rotor 152 by a transmission pair of a nut 154 and a screw rod 155. The adjusting rod 151 is extended deeply into the second receiving chamber 162. When a certain amount of pulse signal is inputted from the signal lead wire 107, the magnetic rotor 152 is rotated by a certain angle under the action of the coil 153. Then, being driven by the transmission pair of the nut 154 and the screw rod 155, the adjusting rod 151 is moved upwardly or downwardly by a certain displacement within the second receiving chamber 162, such that the adjusting rod 151 cooperates with the second valve port 164 to control the pressure change in fluid by changing the flow area in the pressure balancing control circuit 104 as desired.
Valve opening characteristics in the flow path of the above flow path switch control device is substantially the same as that of the first embodiment and will not be repeatedly described herein.
The above description is only for better explaining the technical solutions of the present invention, in which particular embodiments, functions and resulting effects during opening process of the flow path switch control device is explained in detail. Similarly, with these configurations, the same functions and effects will also be achieved during closing process of the flow path switch control device. It is noted that some variation and modifications can be made by those skilled in the art without departing from the principle of the invention. These variation and modifications should also be considered to fall into the protection scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200910208966.3 | Nov 2009 | CN | national |
