JPS62102024A - Vaporizer abnormality sensing device - Google Patents

Abstract

PURPOSE:To provide an automatic sensing of an abnormal condition of a vaporizer by a method wherein a pressure in a surge tank is sensed and stored, a present pressure and a pressure before a specified time are compared to each other, and a fact that a time having no difference between them continues for more than a specified time is detected. CONSTITUTION:A pressure in a surge tank is sensed by a pressure meter 8, its electrical signal is momentarily stored with a memory circuit 15 and outputted after one second as an output from the memory circuit. A comparator 16 may compare the electrical signal from the pressure meter 8 with an output from the memory circuit 15 (an electrical signal of the pressure meter 8 before one second). If there is no difference between both of them, a relay X is turned ON. In case that the relay X is operated for more than a time set by a timer T (for example, 4min), an alarm signal is generated to show that the vaporizer is in an abnormal condition. In this way, a variation in pressure of the surge tank is monitored whereby it is possible to make an automatic discrimination whether the facility is normally operated without generating any clogging at a gas nozzle.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an abnormality detection device for an abnormal situation in which a gas nozzle portion of a vapor riser of an LPG facility freezes, resulting in a decrease in gas amount and poor air suction.

``Prior Art'' A block diagram of a vaporizer for LPG equipment is shown in Figure 2.

That is, the liquefied petroleum gas 2 sent from the storage tank 1 is vaporized in the evaporator tube 3 using the heat of the hot water 4, and the vaporized gas is mixed with air 6 in the mixer 5 to adjust the calories. The pressure in the surge tank 7 is detected by the pressure gauge 8, and the gas is detected based on the pressure signal.

Opening and closing air valves 9.10.

The concave line 11 is a vaporizer.

The gas valve 9 and the air valve 10 installed on the inlet side of the mixer 5 of the vaporizer 11 are mechanically connected to maintain a constant ratio between the gas amount and the air amount, and the gas valve 9 and the air valve 10 are mixed at regular intervals of 4 to 5 seconds. Intermittently turn on and off so that the pressure on the outlet side of machine 5 remains constant.
It is controlled by FF.

However, various causes (for example, signal system malfunctions, etc.)
In this case, an abnormal situation may occur in which the valve operation time is short (for example, 2 to 35 ec).
The appropriate amount of gas and air ratio will be disrupted, resulting in a decrease in air.

If the air ratio decreases, the calories of the mixed combustion gas will increase,
The combustion in the annealing furnace that uses this gas becomes incomplete combustion, resulting in a lower combustion temperature. In addition, soot is generated and a defective pattern appears on the surface of the strip product.

On the other hand, the valve operation time becomes longer (e.g. 4-5 m1n)
There are also breakdowns.

This is because the gas nozzle is clogged and the amount of gas is reduced.
Suction becomes poor. In other words, the ratio of gas and air changes, resulting in a gas-rich state, resulting in the same situation as in the case where the operating time is short, as described above.

In addition, the time chart of the valve operating state and the calorie of the mixed combustion gas in each of the above-mentioned embodiments is shown in Figure 3 a''-c.
It's like this.

a indicates normal time, b indicates short time, and C indicates long time. In the operating state line, the raised portion indicates the opening of the gas valve 9, and the base portion indicates the closing of the gas valve 9.

Also, on the calorie line, the calorie during mixing is high at the beginning and end of mixing, normal in the middle, and becomes the standard calorie when averaged, so if the mixing time is short, the calorie is high and is in an abnormal state.

As mentioned above, causes of abnormalities in the vaporizer include malfunction of the signal system, clogging of the gas nozzle portion of the mixer 5, and the like.

Among these, clogging of the gas nozzle portion of the mixer 5 often occurs.

To explain this phenomenon in detail, it is like a deficiency.

That is, FIG. 4 shows the structure of the mixer 5. When the gas valve 9 is opened, gas is injected from the gas nozzle 12, and at the same time, air in the air pipe 14 is sucked to generate a mixed gas.

The mixed gas is temporarily stored in the surge tank 7 and sent to the consumption equipment.

Here, the amount of mixed gas generated is greater than the consumed amount, and when the amount of mixed gas generated is excessive, the pressure in the surge tank 7 increases, and by detecting this pressure with the pressure gauge 8, the gas valve 9 is activated.
．． Air valve IO is closed to stop generation of mixed gas. Also, when the pressure in the surge tank 7 decreases due to gas consumption in the consuming equipment, the gas valve 9. The air valve 10 is opened to generate a mixed gas. In this way, the gas valve 9. air valve 1
Opening of 0.

Repeated closing (ON-OFI' control) allows the vapor riser to operate normally.

Here, the gas entering mixer 5 is cold (, gas nozzle 12
Freezes at the tip of the gas nozzle, narrowing the opening area of the gas nozzle. In this case, the amount of gas discharged from the gas nozzle 12 also decreases, and therefore the amount of air sucked also becomes extremely small, making the mixed gas rich in gas, and the amount of gas generated also decreases.

In such a case, there is no large difference between the amount of mixed gas generated and the amount consumed, and only the amount that is generated is consumed, and the pressure in the surge tank 7 hardly changes or changes only gradually. FIG. 5 shows pressure changes in the surge tank 7. Under normal conditions, the pressure is a sine wave with a period of 4 to 5 seconds, but when abnormal, there is no pressure change or the amount of change is small.

In case of abnormal situation such as clogging of gas nozzle,
Considering this from the viewpoint of calories as shown in Fig. 3, which has already been described, in the past, workers regularly checked the calories of the vaporizer to discover abnormalities.

``Problems to be Solved by the Invention'' As described above, conventional detection means have the inconvenience of being unable to detect equipment abnormalities when a gas nozzle is clogged unless a person constantly monitors the system.

"Means for Solving Problems" and "Operation" The present invention was made in view of the above circumstances, and its gist is that surge A g91 circuit relay that detects the tank pressure, stores it in a memory circuit, uses a comparator to compare the current pressure with the pressure from a certain period of time stored in the memory circuit, and operates if there is no difference between the two. By operating for more than a predetermined time set by the timer, it is detected that the time with no difference between the two has continued for more than a predetermined time, and it is determined that the pressure in the vapor riser has not changed for more than a certain time, and the vapor riser is activated. The point is that it is possible to automatically detect the occurrence of an abnormality.

"Example" This will be explained in detail below based on the drawings.

FIG. 1 is a sequence diagram showing one embodiment of the present invention, and the same figure shows a circuit that issues an alarm as a vapor riser abnormality when a period of four minutes with almost no pressure change in the surge tank continues.

The pressure in the tank 7 is detected by a pressure gauge 8 and obtained as an electrical signal. The electrical signal is input to the memory circuit 15, the electrical signal is temporarily stored in the memory circuit I5, and is outputted as an output of the memory circuit after one second. The comparator 16 compares the electrical signal of the pressure gauge 8 with the output of the memory circuit 15 (the electrical signal of the pressure gauge 8 one second ago), and turns on the relay X if there is no difference between the two. If relay X operates for longer than the time set by timer T (for example, 4 minutes), it lights up and issues an alarm.

As described above, the electrical signal of the pressure gauge 8 is compared with the electrical signal of one second before, and if there is no difference between the two, the comparator 16
is operated, and when the operating time of the comparator 16 is longer than a predetermined time, it is possible to determine that the vaporizer is abnormal and issue an alarm.

By monitoring changes in the pressure of the surge tank in this way, it is possible to automatically determine whether the equipment is operating normally without clogging the gas nozzle.

"Effects of the Invention" As described above, according to the present invention, abnormality can be automatically detected, and as a result, various effects listed below are achieved.

I) The number of periodic inspections (1 time/hour) can be reduced.

ii) Conventionally, abnormalities could not be detected only during inspection, but with this device, '1ffJ can be detected at all times.

iii) There will be no gas combustion defects in the annealing furnace, which is gas consuming equipment, and product defects will no longer occur.

[Brief explanation of drawings]

FIG. 1 is a sequence diagram showing one embodiment of the present invention, and FIG.
The figure is an explanatory diagram of the vapor riser, Figures 3a-c are time charts showing the mixing state, Figure 4 is an explanatory diagram of the mixer, and Figure 5 is a time chart showing pressure fluctuations in the surge tank.15 -Memory circuit, 16-Comparator X-Relay, T-Timer.

Claims (1)

[Claims] In a vaporizer that intermittently mixes liquefied gas and air, the pressure in a surge tank is detected and stored in a memory circuit, and the current pressure and a certain period of time before that stored in the memory circuit are detected. A comparator compares the pressure between the two, and the relay in the alarm circuit, which activates when there is no difference between the two, operates for more than a predetermined time set by a timer, and detects that the time with no difference between the two has continued for more than a predetermined time. By checking, it is determined that the pressure of the vaporizer does not change for a certain period of time,
A vapor riser abnormality detection device characterized by detecting that the vapor riser is abnormal.