JPH0212095B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to incubators for newborn infants, and more particularly to temperature control of incubators.

BACKGROUND OF THE INVENTION A neonatal incubator is a medical device designed to provide an optimal environment for premature, weak, and sickly newborns. This kind of incubator houses a newborn baby inside a transparent hood made of acrylic or the like, and maintains the temperature and humidity inside the hood at set values by circulating temperature- and humidity-controlled air into the hood. I have to.

Temperature control devices for incubators, which have been widely used in the past, use proportional control to control the incubator heater depending on the size of the difference between the set value and the detected value of the air temperature in the hood (internal temperature). + In-vessel temperature control controlled by integral control, setting a safe temperature range for the in-vessel temperature, and depending on the size of the difference between the set value and detected value of the baby's body temperature, within the above safe temperature range. Then, body temperature control is selectively performed by controlling the internal heater by proportional control, proportional+integral control, or the like.
In addition, body temperature control can control the internal heater according to the size of the difference between the set value and the detected value of the newborn's body temperature, so the newborn's body temperature can be controlled regardless of the size of the internal temperature. It has the advantage of being able to be held almost constant. However, since it is necessary to firmly attach the temperature sensor to the newborn's abdomen, it is a cumbersome process, and there are cases where the temperature sensor comes off from the abdomen or the newborn covers the temperature sensor with his or her arm, etc. , body temperature cannot be detected accurately. Therefore, in the case of newborns, their body temperature changes rapidly immediately after birth (for example, their body temperature is low when they are awake, and their body temperature is high when they are awake), but their body temperature does not change as much a little after birth. Focusing on this, we usually control the body temperature of newborns immediately after birth, and control the internal temperature of newborns a little while after birth.

In this type of incubator, an important issue is to minimize the heat loss of the infant housed in the hood. The causes of heat loss in the infant's body include radiation, transpiration, convection, and conduction, but it has been reported that heat loss due to radiation is the largest, accounting for approximately 43% of the total heat loss.

Radiant heat loss to the baby's body is caused by the temperature difference between the wall temperature of the hood (hereinafter referred to as wall temperature) and the baby's body temperature. When the temperature inside the container is constant, the wall temperature changes linearly in proportion to the room temperature at an intermediate point between the temperature in the room where the incubator is installed and the temperature inside the container. For example, if the room temperature is 20°C and the inside temperature is 33°C, the temperature outside the hood wall will be 26°C and the temperature inside will be 27°C. For this reason, even if the internal temperature is controlled at a constant 33℃,
The baby's body is surrounded by a cold hood, and heat is taken away from the baby's body due to the temperature difference between the wall temperature and the body temperature.

Conventionally, in order to reduce radiant heat loss to the baby's body, the hood has been made double-walled, or an internal hood that is curved in a semicylindrical shape has been installed inside the hood, and the baby's body has been placed inside the hood. Methods have been proposed, such as accommodating

Problems to be Solved by the Invention The above-mentioned method of making the hood double-walled has drawbacks such as an insufficient effect of suppressing heat loss and a complicated structure. The above-mentioned method using an internal hood has problems such as the difficulty of inserting a large number of cords and tubes into the hood from outside the hood and attaching them to the baby's body.

In addition, when conventional incubators are exposed to direct sunlight or the temperature inside the incubator reaches a high temperature of around 36℃,
When the baby's body becomes too warm, its body temperature rises. As a result, it has been reported that the proportion of heat loss due to transpiration instead of heat loss due to radiation increases to about 56%. In this way, it was not possible to prevent the increase in heat loss due to transpiration due to the rise in body temperature.

Means for Solving the Problems The present invention provides an in-vessel heating means for heating the air in the hood housing the baby and a hood heating means for heating the wall surface of the hood. The internal heating means is configured to be controlled according to the magnitude of the difference between a set value and a detected value of the temperature in the hood, such as internal temperature or body temperature of the baby;
The invention relates to an incubator configured to control the hood heating means so that the difference between the internal temperature of the hood and the temperature of the hood wall surface or the outside air temperature of the hood is maintained within a predetermined range.

Therefore, according to the present invention, the temperature inside the hood can be maintained at approximately the set value, and the temperature on the hood wall surface can be adjusted based on the inside temperature of the hood and the outside temperature or the temperature on the hood wall surface that reflects this outside temperature. Since it is possible to control the temperature, it is possible to perform temperature control such that heat loss due to radiation of the baby's body and transpiration at high temperatures is always kept as small as possible.

Embodiment In the present invention, as shown in the drawings, an internal temperature detection section 1, a body temperature detection section 2, a wall temperature detection section 3 are provided, and a hood heater 4 is provided. The internal temperature detection unit 1 is provided, as in the conventional case, below an air intake port for circulating air flow with controlled temperature and humidity inside the hood, for example. The body temperature detection section 2 is provided by fixing a body temperature sensor to the abdomen of the baby. In addition, as the wall temperature detection section 3, a suitable place on the inner wall surface of the hood is installed.
A temperature sensor will be installed. In addition, the hood heater 4 may be configured, for example, by embedding heating wires in the hood, or by making the hood into a double wall, and creating a flow of air with controlled temperature and humidity between the outer wall and the inner wall. It is provided by flowing the part. Incidentally, the above-mentioned system in which heating wires are buried in the hood has been proposed by the present applicant in U.S. Pat. No. 58-203383.

When controlling the internal temperature of the chamber, switch 5 is connected to contact m.
Closed to the side.

The internal temperature setting section 7 sets the internal temperature to _tAO . This set value t _AO and the detection value t _A detected by the internal temperature detection unit 1 are compared in the comparison unit 9, and the output of the difference between the two is sent to the internal heating control unit 1 via the switch 5.
Added to 0. The internal heating control section 10 controls the internal heater 11 according to the output of the difference. As a result, the temperature inside the chamber is controlled to the above _tAO .

Along with this, the above t _A and the detected value of the wall temperature detection section 3
t _R is added to the programmable temperature control unit 12. The adjustment unit 12 calculates the amount of heat required for the hood heater 4 so that the difference between t _A and t _R falls within a preset range, using a prestored program. The hood heating control unit 13 controls the hood heater 4 according to the calculated amount of heat.

Note that an example of the program stored in advance in the programmable temperature adjustment section 12 may be t _A - t _R <6°C. In this case, the hood heater 4 is controlled so that the detected value t _R of the wall temperature does not become lower than the detected value t _A of the internal temperature by 6° C. or more, and heats the wall surface of the hood. In this control, for example, the hood heater 4 is turned on and off to satisfy t _A - t _R <6°C, and when it is turned on, the detected value t _A of the internal temperature and the detected value t of the wall temperature are Depending on the magnitude of the difference with _R , the amount of energization may be controlled by proportional control, proportional + integral control, etc.

According to the above, the temperature inside the chamber can be controlled to the detected value t _AO , and the wall temperature can be controlled in relation to the outside temperature and the temperature inside the chamber.

That is, when the outside temperature is relatively low compared to the inside temperature, the wall surface of the hood is heated by the hood heater 4 so that the wall temperature is relatively greatly increased from the original temperature before heating. Further, when the outside air temperature is relatively higher than the inside temperature, the wall surface of the hood is heated by the hood heater 4 so that the wall temperature does not become much higher than the original temperature before heating. Therefore, heat loss due to radiation and transpiration of the baby's body can be minimized.

Next, when performing body temperature control, the switch 5 is closed to the contact point s side.

The body temperature setting section 8 sets the body temperature to t _BO , and the comparison section 14 compares this t _BO with the detected value t _B of the body temperature detection section 2.
Compare with. The output of this difference is applied to the internal temperature limiting section 15. On the other hand, the internal temperature upper and lower limit setting section 16 sets a safe temperature range of the internal temperature. The internal temperature limiter 15 receives the difference output from the comparator 14, the safe temperature range, and the detected internal temperature _tA . Then, when the current internal temperature _tA is within the safe temperature range, the output of the difference is applied to the internal heating control section 10 via the switch 5. The internal heating control section 10 controls the internal heater 11 according to the output of the difference. As a result, the internal temperature of the chamber is controlled, and the body temperature is controlled to the set value _tBO . At the same time, the programmable temperature controller 12 adjusts t _A ,
The food heater 4 is controlled based on _tR . In this case, the program used in the programmable temperature controller 12 may be the same as that for internal temperature control.

According to the above, it is possible to control the internal temperature to the set value, and also to control the internal temperature, body temperature,
The wall temperature can be controlled in relation to the temperature and outside temperature so that heat loss through radiation and transpiration of the baby's body is minimized.

Further, as described above, the body temperature sensor is attached to the abdomen of the baby, but if the body temperature sensor falls off or is covered by the baby's arm or the like, the detected value will increase rapidly. Furthermore, when the body temperature sensor gets wet with urine, disinfectant, etc., the detected value drops rapidly. If this is left unattended, control will be activated to abnormally lower or increase the internal temperature, but in this example, a safe temperature range for the internal temperature is set, so
Even if an accident like the one described above occurs, the temperature inside the chamber will be controlled within the safe temperature range.

In this embodiment, the wall temperature detection section 3 detects the temperature of the hood wall surface to indirectly perform control related to the outside temperature. However, the outside temperature is directly detected. Good too.

Effects of the Invention As described above, the present invention is configured to control the internal heating means according to the magnitude of the difference between the set value and the detected value of the internal temperature of the hood, and The hood heating means is controlled so that the difference between the wall surface temperature or the outside temperature of the hood is maintained within a predetermined range. Therefore, the temperature inside the hood can be maintained at approximately the set value, and the temperature on the hood wall can be controlled based on the inside temperature of the hood and the outside temperature, or the temperature on the hood wall that reflects this outside temperature. Temperature control can be performed such that heat loss due to body radiation and transpiration at high temperatures is always kept as small as possible.

[Brief explanation of drawings]

The drawing is a block diagram showing an embodiment of the invention. In addition, in the symbols used in the drawings, 1... Inner temperature detection section, 2... Body temperature detection section, 3...
... Wall temperature detection section, 4 ... Hood heater (hood heating means), 7 ... Inner temperature setting section, 8 ... Body temperature setting section,
9, 14...comparison section, 11...internal heater (internal heating means), 12...programmable temperature adjustment section.

Claims (1)

[Scope of Claims] 1. An in-vessel heating means for heating the air in the hood housing the baby body and a hood heating means for heating the wall surface of the hood are provided, and the temperature inside the hood is controlled. The internal heating means is controlled according to the magnitude of the difference between the set value and the detected value, and the difference between the internal temperature of the hood and the temperature of the wall surface of the hood or the outside temperature of the hood is set to a predetermined value. The incubator is configured to control the hood heating means so that the hood heating means is maintained within a range.