JPH0416400Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention is used in the field of heating X-ray tube filaments.

(b) Prior art In X-ray high-voltage equipment that controls fluoroscopy and rapid photography, the X-ray tube filament heating circuit has conventionally been used to control the next rapid photography while performing fluoroscopy at a small focal point of the X-ray tube. In order to quickly perform this, the large focus filament is preheated.

(c) Problems to be solved by the invention Recently, in order to reduce ripples in the tube current, an inverter is often used in the heating circuit to increase the frequency to about 100 to 1 KHz. Particularly in the case of high frequencies, since a heating transformer for high frequencies is used, an inverter circuit is also required for preheating, resulting in high costs.

Therefore, an X-ray tube filament heating circuit has been proposed that does not require a filament preheating circuit, that is, has one heating circuit.

In this case, it should be noted that normally, fluoroscopy uses a small focal point of the X-ray tube because the tube current is small, and rapid photography uses a large focal point because a large tube current is applied to perform imaging in a short time. Additionally, the time required to transition from fluoroscopy to quick photography needs to be as short as 0.8 to 1.2 seconds.

Therefore, during fluoroscopy, it is necessary to preheat the large focus filament to a temperature of about 2.5 A so that no X-rays are generated. Furthermore, on the small focus side, in order to obtain a tube current of about 1 to 2 mA for fluoroscopy,
It is necessary to control the filament current around 3.3A.

In the case of other imaging techniques, only one filament is heated, but in procedures that perform fluoroscopy and rapid photography, two filaments are heated, one for large focus and one for small focus.
A set is required.

In view of the above, an object of the present invention is to provide an X-ray tube filament heating circuit which heats a small focus during fluoroscopy and preheats a large focus for imaging. The present invention is to provide a tube filament heating circuit.

(d) Means for solving the problem The above object is to have one heating circuit, and to form a series circuit of the primary winding of a large focus filament heating transformer and the primary winding of a small focus filament heating transformer. A series circuit consisting of a variable resistor and a fluoroscopy/imaging switch is connected in parallel to the heating circuit, and the common contact of the switch is the primary winding of the large focus filament heating transformer. The variable resistor is connected to the midpoint between the wire and the primary winding of the small focus filament heating transformer, and when the switch is switched to the see-through side contact, the variable resistor connects to the primary winding of the large focus filament heating transformer. This is achieved by configuring a circuit that is connected in parallel and short-circuits the primary winding of the small focus filament heating transformer when the switch is switched to the photographing side contact.

(e) Effect During fluoroscopy, the X-ray tube filament for imaging is connected in series or parallel to the X-ray tube filament for fluoroscopy, and one
Two heating circuits are connected in series to preheat the X-ray tube filament for imaging. At this time, the current is suppressed to such an extent that no X-rays are generated.

(F) Embodiment A preferred embodiment of the present invention will be explained based on FIG. 1.

For comparison with the conventional example, FIG. 2 shows a circuit diagram of the main part of the conventional example. Here, 1 is a power supply, 2 is a power transformer, 3 is an X-ray tube filament heating circuit, and 4 is an
A ray tube filament preheating circuit, 5 and 6 are fluoroscopic/imaging changeover switches, 7 and 8 are X-ray tube filament heating transformers, and 9 is an X-ray tube.

In this conventional example, heating control of a small focal point during fluoroscopy is performed by a heating circuit 3. At the same time, a preheating circuit 4 preheats the large focal point for photographing. When taking a snapshot, the large focus is heated via the heating circuit 3 by switching the changeover switches 5 and 6 to the R side.

Next, in FIG. 1 showing one embodiment of the present invention, the same numerals indicate the same parts, but the preheating circuit 4 is not present. Further, a variable resistor 10 is inserted.

According to this embodiment, when performing fluoroscopy, the fluoroscopy/imaging switch 5 is switched to the F side, so the variable resistor 10 is placed in parallel with the X-ray tube filament heating transformer 8 for large focus. It is connected to the. In addition, the output of the X-ray tube filament heating circuit 3 is
is added to the series circuit of the large and small focus X-ray tube filaments.

Therefore, by controlling the output of the heating circuit 3, a filament current of approximately 3.3 A, which can be used as an X-ray tube current for fluoroscopy, is passed through the small focus, and by passing a small amount of current through the resistor 10, the large focus is controlled. The preheating current is such that no tube current flows, approx.
It can flow 2.5A.

When combining another type of X-ray tube, resistor 1
By changing the resistance value of 0, the preheating current value is adjusted to an appropriate value.

Then, when shooting, turn switch 5 to R.
When switching to the side, only the large focus x-ray tube filament is heated.

In the illustrated embodiment, two X-ray tube filaments are connected in series, but in other embodiments, they may be connected in parallel. in this case,
The resistor is connected in series with the small focus side.

(g) Effects In the present invention, the preheating circuit of the conventional example is removed and only one heating circuit is required, so the circuit is simple and the product can be provided at low cost.

[Brief explanation of the drawing]

FIG. 1 is a main circuit diagram showing one embodiment of the present invention,
FIG. 2 is a circuit diagram of a main part of a conventional example. 3 is the preheating circuit, 5 is the changeover switch, 7 and 8 are X
A ray tube filament heating transformer, 9 is an X-ray tube.

Claims (1)

[Scope of utility model registration request] It has one heating circuit, and a series circuit consisting of the primary winding of a filament heating transformer for large focus and the primary winding of a filament heating transformer for small focus is connected in series to the heating circuit, and A series circuit consisting of a variable resistor and a fluoroscopy/imaging changeover switch is connected to the switch, and the common contact of this changeover switch is connected between the primary winding of the large focus filament heating transformer and the primary winding of the small focus filament heating transformer. The variable resistor is connected in parallel to the primary winding of the large focus filament heating transformer when the switch is switched to the viewing side contact, and the switch is switched to the imaging side contact. An X-ray tube filament heating circuit, characterized in that the primary winding of the small focus filament heating transformer is short-circuited.