JPS5843098B2 - Low-temperature gas injection device for local cooling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a low-temperature gas injection device for local cooling, which is used for rapid cooling of affected areas such as rheumatoid arthritis for pain relief and treatment, cooling anesthesia, and the like.

Conventionally, this type of treatment uses liquid nitrogen at a temperature of -196°C, which is vaporized and heated to become a gas at a temperature of 150°C or less, which is injected directly onto the affected area to prevent frostbite. There is a method of cooling while maintaining the temperature, but in this case, if nitrogen gas is continuously released into the room in a treatment room of a clinic or a hospital with little ventilation, the nitrogen concentration in the room will increase, resulting in a state of oxygen deficiency. , there are drawbacks that have a negative impact on the human body.

Furthermore, conventional methods have been considered to use dry ice or cryosurgical probes, but in this case, the cooling effect cannot be obtained unless they come into contact with the skin, and direct contact poses a great risk of frostbite. be.

Furthermore, it is extremely difficult to obtain gas at a desired temperature using conventional gas injection devices, and for this reason, for example,
In the device shown in Publication No. 5-40336, liquid nitrogen sent from a liquid nitrogen tank to which positive pressure is applied is divided into two passages via valves, and after gasifying the liquid nitrogen in one passage, the liquid nitrogen is transferred to the other passage. However, in order to maintain a constant temperature, liquid nitrogen and gas under positive pressure are controlled by valves and mixed at a constant ratio, which is extremely troublesome and difficult. The problem is not resolved at all.

In order to solve this problem of oxygen deficiency, some devices emit a mixture of oxygen and liquid nitrogen, but it is still difficult to obtain a gas at a constant temperature.

The device of the present invention is designed to solve such problems, and includes a low-temperature gas injection nozzle, an ejector, an oxygen gas supply line having a pressure regulation mechanism connected to the inlet of the ejector, and an oxygen gas supply line connected to the inlet of the ejector. It is characterized by including a liquid nitrogen introduction line at approximately atmospheric pressure connected to the suction port, and a heating mechanism interposed between the outlet of the ejector and the nozzle.

The present invention will be explained in detail below with reference to the drawings.

In the figure, 1 is a liquid nitrogen tank, 2 is a liquid nitrogen supply line to tank 1, 3 is an opening provided at the top of tank 1, and 4
1 is a liquid nitrogen level sensor provided in a tank 1, 5 is an oxygen gas supply line, and 6 is a low-temperature gas injection nozzle for spraying gas onto the affected area.

In the present invention, an ejector 7 is provided, and an oxygen gas supply line 5 having, for example, a Menglan pressure regulator as a pressure regulating mechanism is connected to the ejector 7, and the liquid nitrogen in the tank 1 is supplied to the suction lower b of the ejector 7. Line 8 introduced by atmospheric pressure
The output lower c is connected to the low temperature gas injection nozzle 6 via the heating mechanism 9 having a thermostat, and the room temperature oxygen gas adjusted to a predetermined constant pressure by the pressure regulator is injected into the ejector 7. The liquid nitrogen in the tank 1 is transferred to the ejector via the introduction line 8 by the negative pressure acting on the suction lower b of the feed ejector 7, that is, by the ejector action.
The gas-liquid mixture in the ejector 7 is then heated by the heating mechanism 9 to form a gas at a predetermined temperature, and then ejected from the nozzle 6.

In the embodiment, the heating mechanism 9 blows hot air onto a finned tube through which gas to be heated flows.

Since this heating mechanism 9 is controlled by a temperature control mechanism 11 that is activated by a signal from a temperature sensor 10, the gas temperature can be kept constant.

In the apparatus of the present invention, the inside of the tank 1 is always open to the atmosphere through the opening 3, so that the pressure above the liquid nitrogen level in the tank 1 is approximately atmospheric pressure.

In addition, the liquid level of this liquid nitrogen is constantly detected by a sensor 4,
The amount of liquid nitrogen supplied from the liquid nitrogen supply line is controlled by an adjustment mechanism 12 which receives the output of this sensor 4 as input, and a flow rate control mechanism 13 inserted into the liquid nitrogen supply line 2, and the liquid level in the tank 1 is controlled. Ensure that the level remains constant.

In the device of the present invention, as mentioned above, a mixed gas of oxygen gas and liquid nitrogen is used, so there is no problem of oxygen deficiency, and the liquid nitrogen is taken in at almost atmospheric pressure, Since the area ratio of the inlet and outlet is constant, the mixing amount can be controlled arbitrarily depending on the pressure and flow rate of the oxygen gas, the length of the liquid nitrogen introduction line 8, and the height of the liquid nitrogen liquid level in the tank 1. The ratio can be made similar to that of air, and the mixture having a nearly constant mixing ratio is further adjusted by the heating mechanism 9 installed outside the ejector, so that the mixed gas can be adjusted to the ideal mixing ratio. The temperature can be adjusted with high precision.

In addition, in the device of the present invention, unless oxygen gas is supplied to the ejector 7, liquid nitrogen will not rise up the introduction line 8, so accidents such as only nitrogen gas being released from the low temperature gas injection nozzle 6 and causing oxygen deficiency can be completely avoided. There are great benefits to preventing it.

The oxygen gas used in the device of the present invention is a dry gas with a dew point of about -60°C, but in the vicinity of the inlet lower a of the ejector 7, it comes into contact with the atomized liquid nitrogen sucked through the suction lower b of the ejector 7. The oxygen gas will be below the dew point, and there is a risk that a trace amount of moisture in the oxygen gas will freeze on the lower part a of the ejector 7.

Therefore, in another embodiment of the present invention, the heating mechanism 1 is connected to the oxygen gas supply line 5 at the outer part of the entrance lower a of the ejector 7.
4 is provided to heat this part so that the inlet lower a does not fall below the dew point of oxygen gas.

In the illustrated embodiment, the metal oxygen supply pipe 5 is heated by blowing hot air, and the temperature of the inlet lower a of the ejector 7 is raised by the heat conduction.

In this way, the problem of icing can be eliminated.

In still another embodiment of the present invention, an oxygen concentration sensor 15 is provided near the nozzle 6, and the output of this sensor 15 is added to the concentration alarm mechanism 16, so that, for example, the oxygen concentration in the gas injected from the nozzle 6 is 18%. If the temperature falls outside the range of ~25%, an alarm is issued, and depending on the situation, a solenoid valve inserted in the oxygen gas supply P fin 5 is controlled to stop the supply of oxygen gas.

In this way, dangers due to oxygen deficiency or oxygen excess can be prevented.

[Brief explanation of drawings]

The figure is an explanatory diagram of the device of the present invention. 1... Liquid nitrogen tank, 2... Liquid nitrogen supply line, 3... Tank top opening, 4...
...Liquid level sensor, 5...Oxygen gas supply line, 6...Low temperature gas injection nozzle, 7...
Ejector 7a... Ejector entrance, 7b.
...Ejector suction port, 8...Introduction line, 9...Heating mechanism, 10...Temperature sensor, 11...Temperature Control mechanism, 12...
...Adjustment mechanism, 13...Flow rate control mechanism, 14
・－・・・Heating mechanism. 15...Oxygen concentration sensor 16,...-0
Concentration alarm mechanism.

Claims (1)

[Claims] 1 a low temperature gas injection nozzle, an ejector, an oxygen gas supply line with a pressure adjustment mechanism connected to the inlet of the ejector, a liquid nitrogen introduction line at approximately atmospheric pressure connected to the suction port of the ejector, and the A low-temperature gas injection device for local cooling, comprising a heating mechanism interposed between an ejector outlet and the nozzle.