The primary component of the ultrasonic emulsification equipment is the ultrasonic generator. When the ultrasonic wave propagates, the medium molecules are subjected to the vibration of the acoustic wave energy to generate elastic vibration in the longitudinal direction, which will produce a series of mechanical effects, cavitation effects, and fragmentation effects. Of course, modern ultrasonic emulsification equipment is not composed only of ultrasonic generators. It is a precision surgical operating system that integrates sound, light, electricity and machinery. There are many types of ultrasonic emulsification equipment, but the basic structure is roughly the same, usually composed of ultrasound system, liquid flow system, control system, auxiliary device and so on.
First, the ultrasound system
The ultrasonic system is mainly composed of an ultrasonic generator, a power amplifier, a piezoelectric transducer, an ultrasonic handle, and the like. The operating frequency of ophthalmic phacoemulsification equipment is often between 27 and 64 kHz. Due to the different handles, frequencies such as 28.5, 32, 40, 48 kHz are often used, which is relative to other ultrasound treatment equipment such as ultrasound hyperthermia (1-5 MHz). Ultrasound therapy (0.5 ~ 5MHz) and other equipment is less frequent. Mainly consider the lower frequency sound wave attenuation reduction, less heat and other factors; the role of the power amplifier is to amplify the weak electric signal. Inverting the piezoelectric transducer to produce an inverse piezoelectric effect (transition of electrical energy to acoustic energy), when the frequency of the alternating electric field is ≥ 20 kHz, the piezoelectric transducer generates ultrasonic waves; the transducer is composed of a piezoelectric crystal (such as zirconium) Lead titanate PZT) and the like. After such materials are polarized, if an electric field is applied in the direction of polarization, an inverse piezoelectric effect will occur, and the resulting mechanical vibration will be amplified to the emulsified needle. A stress of >100,000 psi (about 689.5 MPa) can be generated at the end of the emulsified needle, which is sufficient to break the nucleus tissue closure; the ultrasonic handle is a key component of the ultrasonic energy output. It is generally composed of a vibrator, a weight, a transducer, a needle and a jacket. The handle integrates three functions of perfusion, suction and emulsification. 2. The emulsified needle is a special shape of the sound beam. It is a hollow tubular shape, which acts to generate both large ultrasonic energy and at the same time absorb the broken tissue. On the one hand, the silicone tube of the coat should keep the perfusion smooth. On the other hand, it is necessary to cool the emulsified needle.
Second, the flow system
The flow system, also called the injection system, consists mainly of pumps, pipes and handles. With the beginning of the operation of the ultrasonic emulsifier, the pump also produces negative pressure suction. The cleavage nucleus is sucked out by the transfer of the pipe and the handle. Adjusting the pump speed adjusts the flow rate to control the magnitude of the negative pressure output. The pump systems used in the phacoemulsification equipment are: peristaltic pump, venturi pump and diaphragm pump, and the diaphragm pump has been eliminated. The advantage of the peristaltic pump is that the negative pressure is stable and reliable. Its mechanism is: relying on the rotation of the drum to generate a negative pressure in the pipe, no matter what speed the gear rotates. The liquid passing through the pipe is constant, which ensures a constant flow. Allow the surgeon to have enough reaction time to improve the stability of the anterior chamber. Its disadvantage is that the emulsifier head must be able to generate a negative pressure when there is a blockage, so the suction start is relatively slow. The Venturi pump, also known as the Venturi pump, provides a powerful vacuum suction, but has no peristaltic pumping for the stability of the anterior chamber. The Venturi pump uses compressed gas instead of the liquid flow of the peristaltic pump to generate a negative pressure. The mechanism is that the compressed gas generates a high-speed air flow through the pipe, so that the air in the container is sucked out to generate a negative pressure. Further, the crystal emulsion is aspirated. It has the advantage of high pressure attraction soon after startup. The ultra-milk glass-cutting machine usually uses a Venturi pump because it must meet the powerful negative pressure required for posterior segment vitrectomy.
Third, the control system
The control system uses multiple independent microprocessors. The ultrasound system, the flow system, and the interface system are separately controlled. Multiple emulsification modes are available depending on the handle. Such as twisting mode, jet water emulsification mode and traditional emulsification mode, etc.: can control the modulation mode of ultrasonic energy, such as pulse mode, blast mode and cold super-milk mode; can control the suction rate O-60m‰in and negative pressure 10 - 650mmHg (1mmHg = 133.322Pa); in the control of the user interface system, the surgical steps and parameters can be personalized, visualized, graphical interface, animation, voice prompts and confirmation; in addition, the control system also has Wireless remote control surgery and other functions.
Fourth, auxiliary equipment
The electrocoagulation handle and the vitrectomy handle are the main components of the super-milk aid. Coag handle: Supply an isolated bipolar current to a conductor (such as tweezers) for hemostasis. The current intensity of hemostasis is crucial, too low and no hemostatic effect. Too high will cause tissue burns. The glass-cutting handle is a reciprocating or oscillating vitreous resection knife that provides suction and ablation. The cutting speed of the handle is adjustable from 10 to 800 times, min. There is vacuum suction during cutting. The cutting frequency, flow rate, and vacuum suction can be preset.