投稿者: suzanna

What Is a Syringe Pump?

A Syringe Pump is a machine that continuously pumps or aspirates a precise volume and speed of solution or medicine from a syringe.

There are two types of syringe pumps: those for medical use and those for research and development.

Syringe pumps move the plunger of a syringe at a constant speed according to the size of the syringe in order to pump or aspirate precisely at a preset volume and time.

Figure 1. Syringe pump

Uses of Syringe Pumps

There are two main types of uses for syringe pumps: medical and research.

The purpose of syringe pumps is to pump or aspirate a precise amount of solution or drug at a constant speed while controlling the flow rate.

1. Syringe Pumps for Medical Use

Medical syringe pumps are used to administer exact and precise doses of medication in doses of 50 mL or less per dose. Compared to infusion pumps that use elastic tubing, syringe pumps use rigid syringes to ensure accurate infusion. 

2.Syringe Pumps for Research and Development

Syringe pumps for research and development are used in applications that require precise, pulseless, metered volume infusion.

Applications include flow micro-reactions, reagent drops, pharmacological and animal experiments, and injection into analytical instruments.

Fluid volumes may be very small and may have additional characteristics that make them unsuitable for clinical use.

Other applications include the dispensing of various fluids such as adhesives, silver, solder paste, grease, chemicals, liquid crystals, etc., in the manufacture of components and assembly lines in production.

Principle of Syringe Pump

Figure 2. Principle of the syringe pump

A syringe pump pump delivers a constant flow of liquid by fixing the outer cylinder of a syringe and pushing out the inner cylinder with the power of a motor. A stepping motor, which is easily adjustable and can operate at a constant speed, is generally used as the motor.

When syringes are used manually, it is extremely difficult to adjust the flow rate and speed, but with syringe pumps, the motor pushes the syringe at a constant speed, enabling highly accurate flow rate adjustment and pulsation-free pumping.

How to Select a Syringe Pump

As mentioned above, you must first select a different medical/research and development pump for your application. Then, according to your purpose, you should use the one equipped with the necessary functions.

1. For Medical Use

Syringe pumps for medical use are available for 5, 10, 20, 30, 50, and 100 mL syringes, respectively. It is necessary to select a product that matches the volume of drug solution to be used and the desired inflow volume.

Some products may alert the user with a buzzer sound until the syringe is properly installed as a safety measure. This is to prevent siphoning, a phenomenon in which a large amount of drug is injected into a syringe pump installed at a height higher than the patient’s body due to a drop-off if the syringe pusher is not fixed in place.

Others are equipped with wireless LAN for remote monitoring of pump operation, pulse injection (intermittent injection) settings, and display of gamma volume calculations linked to the injection rate value of the Syringe Pump itself. Some products also allow two syringes to be attached simultaneously to administer different drugs or to perform continuous infusion.

Figure 3. Danger of siphoning phenomenon

2. For Research and Development

There are a variety of sizes available, from those for micro-liter liquid volumes to those for 100-mL liquid volumes. First, it is necessary to select the scale that best suits your application. The basic functions also vary depending on the product, ranging from simple pumping-only models to those capable of pumping/aspirating and programmed pumping.

The control unit can be as simple as a dial to set the flow rate, or as sophisticated as a microcomputer-equipped type. The remote control cable can also be added to allow operation via remote control. For example, the drive unit can be installed in a cold room and the flow rate can be controlled from outside.

Other notable features include the ability to pump high-viscosity liquids such as CMC solutions. Some syringe pumps are pre-installed with syringe data from major manufacturers and can be set up so that all you have to do is make a selection.

Other Information on Syringe Pumps

1. Incidents Related to Syringe Pumps

Incidents related to Syringe Pumps include the following

Incorrect input of pump flow rate setting
Syringe pumps are used to continuously administer medication at a precise volume and rate, and incorrectly entered flow rates can result in serious incidents that can be fatal to patients. Other examples of setting input errors include mistakenly entering the wrong flow rate for Drug A and Drug B, and mistakenly entering the wrong flow rate units.

Failure of the pump’s air bubble detector
Syringe pumps are usually designed to detect air bubbles and automatically stop pumping, but there have been reports of cases where the pumps do not stop and air is pumped to the patient side due to equipment malfunction. Even if maintenance and inspections are performed, such cases can still occur, so it is important to enter the expected volume when using the pump.

In addition, as a background or factor in these cases, lack of knowledge and experience of medical personnel was reported in many cases. Familiarization with the procedure manual and reeducation on how to use it are also important to prevent these cases from occurring.

What Is a Wattmeter?

A wattmeter is a device used to measure the power consumed by electrical and electronic equipment. A wattmeter is inserted between a power source and a load and calculates the power from the product of the applied voltage and the flowing current (voltage x current).

In AC, there is a phase difference between the voltage and current, which affects the power. Therefore, it is important to measure them at the same time. In recent years, the quality of power supplies has also become increasingly important, and some have functions to evaluate the waveforms of voltage, current, and power.

Usage of Wattmeters

In recent years, the need for electricity meters to monitor the power consumption of various electrical and electronic equipment has increased significantly due to the growing emphasis on reducing energy consumption in addressing global environmental issues.

Their applications range from general households for the purpose of saving electricity to power monitoring systems for factories and buildings. In addition to measuring power, development and production sites require high-precision, highly functional wattmeters for various evaluations such as phase angle, power factor, harmonics, flicker, distortion, and noise.

Principles of Wattmeters

Since electric power is the product of voltage and current, it can be calculated by measuring voltage and current, respectively. In the case of direct current, both voltage and current are constant. Therefore, power can be calculated by measuring each separately. But in the case of alternating current, the phase difference between voltage and current must be considered. As such, the instantaneous value of each must be measured continuously at the same time.

The instantaneous power calculated as the product of the values of voltage and current is integrated and averaged over one cycle to give the total electric power. This is the power actually consumed by the load and is called effective power. If the effective value of voltage is V, the effective value of current is I, and the phase difference between voltage and current is θ. Effective power can also be calculated as V × I × cos(θ).

AC power also includes reactive power and apparent power. Reactive power is the power that travels back and forth between the power source and the equipment without being consumed by the load and is due to the coil and capacitor components of the load. Reactive power can be calculated by V × I × sin(θ). Apparent power is the power that must be supplied from the power source, and the relationship equation is apparent power squared = active power squared + reactive power squared.

What Is a Cable Clamp?

A cable clamp is a device used to insert and securely fasten a cable (an electric wire consisting of insulation and sheath used in electrical and control systems) into the enclosure of a control panel or operation panel or into a device.

The main functions of a cable clamp are as follows:

External environmental protection: Prevents dust, dirt, and moisture from entering through openings in enclosures such as control panels.

Retention: Securely holds cables in place and prevents them from loosening under external mechanical tension or vibration.
Sealing: Prevents dust and water from entering the cable from the outside.

Usage of Cable Clamps

Cable clamps, also known as “wire penetration hardware,” are used to penetrate the walls of enclosures by attaching to cable intakes (connection holes) in enclosures such as control panels. Cable clamps are used at various points in the indoor and outdoor wiring of electrical and control equipment.

They prevent dust and water from entering the enclosure and equipment of control panels and operation panels, prevent disconnection due to vibration or pulling, and securely fasten and retract cables.

There are also cable clamps made of materials such as stainless steel and polyamide resin (PA). It is especially important to select a material suitable for the operating environment, such as weather resistance for outdoor use, oil resistance for an oil-covered environment, and heat resistance for a high-temperature atmosphere.

In addition to cable clamps, devices for pulling cables into enclosures such as control panels. A cable clamp is used when pulling in one cable at a time, and a ground clamp is used when pulling in multiple cables at once.

Principle of Cable Grounding

When selecting the size of the cable clamp, select a size suitable for the finished outer diameter of the cable to be used and the opening dimensions of the mounting hole. In particular, the cable gasket (bushing) is available in sizes “a” to “c” and “f” to “c”, where the hole diameter is machined by the user. The size should be selected appropriately for the finished O.D. of the cable.

The body is cylindrical in shape, and the male thread is inserted into the mounting hole drilled in the enclosure of a control panel, etc., with a gasket inserted between the threads.

The cable is firmly secured and sealed on the outer surface of the cable by pressing down on the gasket (bushing) when the tightening clamp is screwed in and tightened.

What Is a CCFL?

CCFL (Cold Cathode Fluorescent Lamp) refers to a type of fluorescent lamp called a cold cathode tube.

Conventional fluorescent lamps, such as hot cathode fluorescent lamps (HCFLs), emit electrons from the emitter by heating the electrodes, while CCFLs emit electrons and light up without heating the electrodes.

Therefore, since it does not have a filament, the tube as a single unit boasts an extremely long life.

Furthermore, they have the advantage of high color rendering and luminance and can be brightly illuminated with little power consumption.

Applications of CCFLs

CCFLs have been used as light sources for industrial equipment for more than 40 years.

They were mainly used in places where blinking lights (on/off) were required, such as backlights for monitors, reading light sources for fax machines and scanners, and decorative light sources for amusement equipment.

Later, with the spread of PCs and LCD TVs, they became indispensable for LCD monitors.

In addition, LEDs are now also used for lighting. 

Specifically, CCFLs are suitable for use in offices, condominiums, commercial facilities, hospitals, nursing care facilities, schools, convenience stores, factories, poultry farms, etc.

Principle of CCFLs

CCFLs are similar to fluorescent lamps but differ in that they emit electrons without heating the electrodes.

First, they emit ultraviolet light. The ultraviolet light is emitted when the excited Hg returns to its ground state upon collision with an electron.

However, it is inefficient because the electrons are said to be very small (with a radius of about 0.282 x 10-5 nm), which means that the probability of colliding with a Hg atom (with a radius of 0.141 nm) is low.

As a countermeasure, inert gases such as Ar or Ne are enclosed to enhance the efficiency of Hg excitation.

These substances play a major role in maintaining the discharge and facilitating energy transfer to Hg.

Next, conversion to visible light is performed. Phosphors coated on the inner wall of the tube are converted to visible light by excitation with ultraviolet light.

By changing the type of phosphor, various colors of visible light can be emitted.