JPH057484Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device for detecting gas pressure supplied to a gas engine, and in particular, the present invention relates to a device for detecting gas pressure supplied to a gas engine. This invention relates to a pressure detection device.

[Conventional technology]

Conventionally, as shown in FIG. 3, a branch pipe 6 is provided between an inlet joint 1 of a gas pipe supplied to a gas engine 5 and a solenoid valve 2, and the pressure of the gas supplied to the branch pipe 6 is detected. Those equipped with a semiconductor pressure sensor or a mechanical pressure switch 8 are known. When the gas engine 5 is stopped, the supplied gas pressure is constant, but when the gas engine 5 starts operating, the gas is intermittently supplied to the gas engine 5, so the rotation of the engine changes. The gas pressure on the inlet side varies depending on the number of cycles and the number of cycles, and in the worst case, it may become negative pressure. When the gas engine 5 is in operation, the gas pressure between the gas engine inlet and the gas inlet joint 1 changes depending on the operating conditions as shown in Figure 4, with the vertical axis representing the gas pressure and the horizontal axis representing time. This waveform attenuates as it moves away from the gas engine 5. Furthermore, the smaller the number of cycles, the larger the pulsation width, and the period of pulsation is determined by the number of rotations.

Gas is supplied from the gas supply source to a plurality of demand destinations including the gas engine, and the gas engine 5
If the gas demand at other gas demand destinations increases and the gas pressure at the supply source decreases, and if there is a pulsation in gas pressure as described above, the gas engine 5 will suck in gas and reduce the demand for other gas. It is expected that the use of gas at the destination will become impossible. Therefore, when the gas pressure on the supply side falls below a certain predetermined gas pressure, it is necessary to stop the gas engine 5 and install a semiconductor pressure sensor or mechanical pressure switch 8, etc. to detect the gas pressure on the supply side. is provided.

[The problem that the idea attempts to solve]

In the above-mentioned known technology, gas passes through a gas inlet joint 1, a solenoid valve 2, and a gas pressure regulator (governor).
4 to the gas engine 5, the gas pressure on the gas inlet side causes pulsations that change with the operating state (rotational speed) of the gas engine 5, as shown in FIG. A sensor or pressure switch 8 receives this pulsating gas pressure.

Therefore, when using a semiconductor pressure sensor, it is necessary to install an integration circuit that converts the pressure into electricity and then integrates it for a certain period of time to calculate the average value to prevent the influence of pulsation, or to calculate the maximum value detected during a certain period of time. A circuit that calculates the average value of the minimum values is provided to prevent malfunctions due to pulsation, but such a circuit increases costs and inevitably reduces durability because pulsation is applied to the pressure receiving plate. In addition, in the case of a mechanical pressure switch, the response speed is slower than the pulsation cycle, so it is used as is, but the durability of the pressure receiving plate is similarly reduced. Furthermore, in either case, deviations in set values were likely to occur due to the influence of pulsation, and variations in setting accuracy were likely to occur.

Utility Model Application No. 61-198557 discloses a fuel passage from the vaporizer to the mixer in a liquefied gas supply device equipped with a vaporizer for reducing the pressure of liquefied gas and a mixer for mixing the reduced pressure vaporized liquefied gas with air. A pulsation absorption mechanism for absorbing engine pressure pulsations is provided in the pulsation absorption mechanism, and this pulsation absorption mechanism is connected to an absorption chamber connected to a fuel passage, a back chamber in contact with this absorption chamber via a diaphragm, and a pulsation absorption mechanism provided in this back chamber. A configuration including a spring acting on a diaphragm is disclosed. However, this pulsation absorption mechanism attempts to absorb the pulsation of the gas pressure as a whole flowing through the fuel passage, but does not attenuate the pulsation of the gas pressure in the portion led to the pressure detection means. Since it utilizes the displacement of a diaphragm, deterioration over time is unavoidable.

The object of the present invention is to prevent gas pressure pulsations from being applied directly to the pressure sensor or pressure switch.

[Means to solve the problem]

The above problem is solved in a gas pressure detection device for a gas engine, which includes a branch pipe provided in a gas supply pipe that supplies gas to a gas engine, and a pressure detection means connected to the branch pipe. means connected to the branch pipe via a pulsation damping means;
This is achieved by configuring the pulsation damping means to include an orifice with a hole diameter of 0.08 to 0.16 mm.

[Effect]

The gas pressure in the gas supply pipe, which includes pulsations caused by the intermittent intake of gas by the gas engine, is applied to the pressure detection means after the pulsations are attenuated by a pulsation damping means consisting of an orifice with a hole diameter of 0.08 to 0.16 mm. . Since the pulsation of the gas pressure applied to the pressure detection means is attenuated, the amount of displacement of the pressure receiving plate of the pressure detection means is also reduced.

〔Example〕

An embodiment of the present invention will be explained with reference to FIGS. 1 and 2.
Electromagnetic valves 2 and 3 that connect to the gas inlet joint 1 to open and close the gas passage, and a gas pressure regulator 4 that maintains a constant gas pressure are provided in series in this order to form the gas supply pipe 20.
The outlet of the gas pressure regulator 4 is connected to the inlet of the gas engine 5. A branch pipe 6, which is a vertical branch pipe, is provided between the gas inlet joint 1 and the electromagnetic valve 2, and a flange 7 provided with an O-ring groove 7A is integrally joined to the end of the branch pipe 6. A flange 9, which also has an O-ring groove 9A, is connected to the flange 7 by screws 12, sandwiching an orifice 10 serving as a pulsation damping means in a sandwich-like manner. A semiconductor pressure sensor 8 serving as pressure detection means is integrally joined to the flange 9. O-rings 11 are installed in the O-ring grooves 7A and 9A, and the flange 7A and the semiconductor pressure sensor 8 are connected in a secure manner, and the gas inlet joint 1 and the semiconductor pressure sensor 8 are communicated with each other, and the gas is not allowed to enter the atmosphere between them. The structure is designed to prevent leakage. Further, the orifice 10 has a hole 13 in the center, and both ends of the hole 13 are machined into a cone. The gas engine 5 drives a heat pump (not shown) that uses Freon as a refrigerant.

The appropriate diameter of the hole 13 is 0.08 to 0.16 mmφ as a result of experiments to find a size that suppresses the pulsation of gas pressure and does not slow down the response speed of the pressure sensor. If the diameter of the orifice hole is increased, the response speed becomes faster, but the pulsation is not sufficiently attenuated and the durability of the pressure receiving plate is shortened.If the orifice hole diameter is made smaller, the response speed becomes slower and drilling becomes difficult, increasing the processing cost.

According to this embodiment, since the semiconductor pressure sensor 8 is communicated with the gas inlet joint 1 via the orifice 10, the pulsations of gas pressure are not directly applied to the semiconductor pressure sensor, and the pulsations are attenuated by the orifice 10. In addition to semiconductor pressure sensors, this reduces deviations in the set values of the pressure sensor, and attenuates pulsation, reducing the amount of displacement of the pressure sensor's pressure receiving plate, resulting in a longer life. Further, dust and the like are prevented from entering the pressure receiving plate, and malfunction of the pressure sensor is prevented.

Although the above embodiment uses a semiconductor pressure sensor as the pressure detection means, the same effect can be obtained by using a mechanical pressure switch.

[Effect of idea]

According to the present invention, the pressure detection means for detecting the pressure of gas supplied to the gas engine has a hole diameter of 0.08 to
Since it is communicated with the gas supply pipe through a pulsation damping means including a 0.16mmφ orifice, the pulsation of gas pressure is damped by the orifice and applied to the pressure detection means, and the displacement of the pressure receiving plate of the pressure detection means is reduced. It does not absorb the pulsations in the gas pressure inside the gas supply pipe, but only attenuates the pulsations in the pressure applied to the pressure detection means, which reduces the cost and requires a small device. There is no moving part of the pulsation damping means,
It has the advantage that even if the frequency of pulsation is high, its durability does not deteriorate.

[Brief explanation of drawings]

Fig. 1 is a piping diagram showing an embodiment of the present invention, Fig. 2 is a sectional view showing details of the part shown in Fig. 1, Fig. 3 is a piping diagram showing an example of the prior art, and Fig. 4 is a piping diagram showing the prior art. FIG. 2 is a conceptual diagram showing the pulsation of gas pressure at 5... Gas engine, 6... Branch pipe (branch pipe),
7, 9...flange, 8...pressure detection means (semiconductor pressure sensor), 10...pulsation damping means (orifice), 11...O ring, 20...gas supply pipe.

Claims (1)

[Scope of utility model registration request] A gas pressure detection device for a gas engine comprising a branch pipe provided in a gas supply pipe that supplies gas to the gas engine, and a pressure detection means connected to the branch pipe, wherein the pressure detection means includes a pulsation damping means. A gas pressure detection device for a gas engine, characterized in that the pulsation damping means is connected to the branch pipe via the branch pipe, and the pulsation damping means includes an orifice having a hole diameter of 0.08 to 0.16 mm.