What is the difference between a constant pressure dispensing funnel and a normal dispensing funnel?

1. Constant pressure separating funnel.

A constant pressure separating funnel is a type of separating funnel. Like other dispensing funnels, it can be used for dispensing, extraction, and other operations. Different from other separating funnels, the constant pressure separating funnel can ensure that the internal pressure remains unchanged, one is to prevent sucking, the other is to make the liquid in the funnel flow smoothly, and the third is to reduce the effect of the increased liquid on the gas pressure, so as to be more accurate when measuring the volume of gas.

2. Ordinary separating funnel.

The separating funnel is a kind of glass experimental instrument, especially involving a separating funnel for chemical experiments. Including the bucket body, the bucket lid that covers the upper mouth of the bucket body. The lower mouth of the bucket body is provided with a piston of a three-way structure, and the two crosses of the piston are connected with two downpipes respectively.

Using the utility model, can make the experimental operation process conducive to control, reduce labor intensity, when the amount of liquid that needs to be separated is large, only need to move the tee of piston can flow to the lower tube at the same time two kinds of liquid in the bucket body, can be completed at one time without replacing the container. In the junior high school stage, the main function of the separating funnel is to control the rate of chemical reactions. This device is a kind of experimental vessel with good function in scientific research and chemical experiments.

The ordinary separating funnel drip liquid is that when the internal and external atmospheric pressure is equal, it will no longer drip downward, while the constant pressure separating funnel will continue to drip down until the liquid is finished.

First, the structure is different1. Drip funnel: The drip funnel is composed of a main body, a drip speed adjustment device, and a drip pipe.

2. Separating funnel.

The separating funnel liquid is composed of a bucket body, a bucket cover, a piston, etc.

Second, the use is different1. Drip funnel: The drip funnel is used to be volatile.

It is used when exposed to air-reactive substances or when the drip rate is maintained.

2. Separating funnel: The separating funnel is used to separate the two liquids formed after extraction.

Third, the characteristics are different1. Drip funnel: The drip funnel is convenient for adding liquid, and there will be no gas leakage when adding liquid, and the reaction rate can be controlled by controlling the rate of dropping.

2. Separating funnel: The separating funnel can control the speed of liquid dripping, which can prevent gas from escaping from the funnel.

Drip funnel withSeparate funnelsDifferences:

First: From the point of view, the separating funnel is more expensive.

Second: Functionally, the separating funnel is stronger and the workmanship is finer.

Third: In terms of shape, the drip funnel is a conical shape above and a slender tube below, with a plane projection in a Y shape, while the separating funnel is a large tube with small ends and a plug on the top and a valve on the bottom, shaped like a roasted chicken thigh.

Fourth: in terms of function, the funnel is generally used to use filter paper pad glass rod drainage for solid-liquid two-phase separation, while the separating funnel is used to separate two liquids that are immiscible with each other.

Key features of the drip funnel:

1. Control the droplet acceleration of the liquid when preparing some gases (especially toxic gases), so as to control the reaction speed, especially when some reactions are more violent, smoke is produced in the container or colored gases are prepared during the reaction, such as chlorine gas in the laboratory.

In particular, permanganate is listed as pure sun potassium.

Reaction with concentrated hydrochloric acid to produce chlorine gas), nitrogen dioxide, manganese dioxide catalyzed hydrogen peroxide.

Decomposition to produce oxygen and laboratory-made acetylene.

When waiting for gases, it is not convenient to control the reaction rate by observing the speed of liquid dropwise addition in the reaction vessel.

2. For some reversible reactions.

By continuously adding the liquid dropwise and distilling the reaction product, the equilibrium is continuously shifted in the direction of the target product, and in the experiment, the lower end of the dropping funnel is extended below the liquid level. In the existing grinding glass instrument, whether it is an atmospheric pressure cylindrical drip funnel or a constant pressure cylindrical drip funnel, the lower end of which is a double-layer casing, and the inner tube is slightly longer than the outer tube, which is mainly used for dropping liquid in organic reactions, and the outer tube has a grinding mouth, which is used to insert the reaction vessel to seal the contact part to reduce the yield.

The above content reference: Encyclopedia - Liquid Separation Funnel.

First, the use is different.

1. Constant pressure dripping funnel: The constant pressure dripping funnel is mainly used to add reaction materials dropwise during reaction.

2. Constant pressure separating funnel: Constant pressure separating funnel is mainly used for separating and extracting liquid organic substances.

Second, the classification is different.

1. Constant pressure drip funnel: In fact, it is a constant pressure separating funnel, which can not require additional operations like a separating funnel.

2. Constant pressure separating funnel: Separating funnel is usually divided into spherical, pear-shaped, and constant pressure.

Third, the characteristics are different

1. Constant pressure dropping funnel: there will be no gas leakage when adding liquid, and the funnel that can control the reaction rate by controlling the rate of dropping, or can be installed on the reaction device for dropping liquid.

2. Constant pressure separating funnel: The constant pressure separating funnel can ensure that the internal pressure remains unchanged, which can prevent sucking, make the liquid in the funnel flow down smoothly, reduce the influence of the increased liquid on the gas pressure, and make it more accurate when measuring the volume of gas.

1.Constant pressure separating funnels are mainly used for the separation and extraction of liquid organic substances.

2.The constant pressure dripping funnel is mainly used to add reaction materials dropwise during the reaction.

3.Separating funnels are usually divided into spherical, pear-shaped, constant pressure, and sometimes cylindrical funnels.

4.In many experimental operations, people mostly use long-neck funnel or spherical separating funnel for some objective reasons, but in fact, using a constant pressure funnel will make the experiment more accurate.

5.Generally, a constant pressure funnel is used in a closed system, such as most organic synthesis experiments, because its organic solvent is volatile, and it needs to isolate air (oxygen).

6.The constant pressure dropping funnel is tightly connected to the flask (or other reaction vessel) in the above experiments (usually a standard grinding mouth), and the funnel is also sealed with a stopper.

7.In addition, because the constant pressure dropping funnel is a conventional instrument for synthesis experiments, all of which are standard grinding ports and easy to connect, some dropping processes that do not require closure or loose conditions (such as dropping water) are also commonly used.

8.Sometimes, when measuring the volume of gases, a constant pressure funnel is often used to eliminate the effect of air pressure caused by the liquid, which can reduce the error.

9.In addition, the use of a constant pressure funnel allows the liquid to flow out better and also speeds up the experiment.

A separating funnel is a glassware commonly used in laboratories to separate two immiscible liquids. The principle is based on the difference in specific gravity between the two liquids and the action of gravity.

Specifically, when two immiscible liquids are mixed together, the denser liquid sinks underneath and the less dense liquid floats on top. The separating funnel is designed to take advantage of this principle to release the mixture through the lower part of the funnel, so as to achieve the purpose of separating two liquids.

The structure of the separating funnel is peculiar, with a narrow upper end, a wider lower end than the skin, and a conical collection area in the middle. During the use of the separating funnel, the mixed liquid is first poured into the funnel and then waits for a while for the two liquids to separate. After that, the lower piston or swivel tap is opened, and the denser liquid flows out along the bottom of the funnel, while the less dense liquid remains in the upper part of the funnel.

In this way, the two liquids can be collected separately.

It is important to note that the separating funnel can only be used to separate two immiscible liquids, and the relative density difference between the liquids must be large enough, otherwise the separation effect will be poor. In laboratory operations, there are also safety precautions to be taken when using a separating funnel, such as ensuring that the lower end of the funnel is placed in a receiving container to avoid spilling liquids that could cause safety concerns.

Principle of the separating funnel:

Two immiscible solutions are stratified together, the dense one is below, the density is lower and the lower one is higher, the lower liquid can flow out from the small mouth, and after the belt is exhausted, the upper liquid can be poured out from the upper mouth to achieve the purpose of separating.

Dispensing funnel operation:

Before using the separating funnel, take out the core on the neck of the colander key, coat it with petroleum jelly, and insert it into the plug groove to rotate to make the oil film uniform and transparent, and rotate freely. Then close the, fill the funnel with water, check whether the is leaking, and the non-leaking separating funnel can be used. To prevent impurities from falling into the funnel, the plug on the mouth of the funnel should be closed.

When the liquid in the separating funnel flows downward, the piston can control the flow of the liquid, and to stop the reaction, the piston must be tightly closed, so Lingxiang can immediately stop the dropping of liquid. When discharging liquid, the groove on the grinding plug and the small hole in the neck of the funnel should be aligned, so that the air inside and outside the funnel is connected, and the pressure is equal, so that the liquid in the funnel can flow out smoothly.

Purpose of separating funnel:

Solid-liquid or liquid-to-liquid reaction generator: control the amount of liquid added and the size of the reaction rate.

Substance separation and purification: separating the two immiscible liquids formed after extraction.