Which company is good for low-temperature liquid ammonia pumps?

Is a low-temperature liquid ammonia pump a piston pump?

It seems that both centrifugal and plunger types work, right? We need to know that too!

The dark blue pumps are nice, and they also have quite a high sales volume

Given the risk of ammonia leakage, it is best to use a shielded pump!

Ammonia pumps produced by Shanghai Dalong, Weifang Shengjian, and Wenzhou Gunai are all suitable.

Overview of shielded pumps: English name: Shielded pump. In conventional centrifugal pumps, the impeller shaft is connected to the motor shaft through a coupling, allowing the impeller to rotate together with the motor. A shielded pump, on the other hand, is a seal-less pump; both the pump and the drive motor are enclosed within a pressure vessel filled with the medium to be pumped. This pressure vessel has only static seals, and an electrical winding set is used to generate a rotating magnetic field that drives the rotor. This design eliminates the rotating shaft sealing mechanism found in conventional centrifugal pumps, thereby achieving complete leaklessness. 　　 A shielded pump combines the pump and the motor together; the rotor of the motor and the impeller of the pump are mounted on the same shaft. A shielding sleeve is used to separate the rotor from the stator of the motor. The rotor rotates within the medium being transported, with power being transmitted to it through the magnetic field of the stator. 　　Furthermore, the manufacturing of shielded pumps is not complex; their hydraulic sections can be designed and manufactured according to the structural formats commonly used in centrifugal pumps as well as relevant standard specifications. 　　 Structural type: 1. Integrated structure of motor and water pump, with the water pump and motor connected on the same axis ； 　　2. The inner side of the motor stator and the outer side of the rotor are equipped with shielding sleeves, and the inside of these shielding sleeves is connected to the inside of the pump ； 　　3. The installation methods are divided into horizontal and vertical types. 4. The motor does not have a cooling fan; it is cooled by the circulating medium between the stator and rotor, with additional cooling being provided via the surface of the motor frame. 　　 Product features: 　　 　　1. Integrated motor and pump design, with all components using static seals to ensure complete leakage-free operation of the electric pump ； 　　2. A fully enclosed, leak-proof design that enables the transport of toxic and hazardous liquid substances ； 　　3. The use of a shielded water-cooled motor along with the elimination of cooling fans enables this pump to operate in a low-noise manner, making it suitable for applications where low environmental noise levels are required ； 　　4. Graphite sliding bearings lubricated by a conveying medium result in lower operating noise and eliminate the need for manual oiling, thereby reducing maintenance costs ； 　　5. The vertical structure can be installed on pipelines like a valve, making installation easy and quick; moreover, during maintenance, only the motor and impeller need to be removed, without the need to take down the pipelines. 　　6. It can be installed and operated in conjunction with shock absorbers or shock pads, reducing the noise generated by the electric pump during operation. Application areas: 1. Circulating water systems for geothermal heat pump air conditioning systems; 2. Lithium bromide air conditioning units; 3. Circulating water systems for heating applications; 4. Fire fighting water pressure enhancement systems; 5. Tap water pressure enhancement systems; 6. Transportation of toxic and hazardous liquids

A plunger pump is an important component in hydraulic systems. It relies on the reciprocating movement of the plunger within the cylinder block to change the volume of the sealed working chamber, thereby enabling oil suction and oil compression. Plunger pumps feature high rated pressure, compact structure, high efficiency, and easy flow regulation, and are widely used in applications that require high pressure, large flow rates, or flow control, such as hydraulic presses, construction machinery, and ships. Table of Contents Structure Types Operating Stages Main Features 　　 Structure Types 　　Plunger pumps are divided into two representative structure types: axial plunger pumps and radial plunger pumps ； As radial piston pumps are a type of high-efficiency pump with a high level of technical complexity, and as domestic production of such pumps accelerates, they will inevitably become an important part of the piston pump industry ； For details, please refer to the encyclopedia on radial piston pumps 　　 ； The following explanation is given using an axial piston pump as an example only. 　　An axial piston pump operates by utilizing the volume changes generated by the reciprocating motion of pistons parallel to the drive shaft within the piston cylinders. Since both the plunger and the plunger hole are circular components, a high degree of precision in their fit can be achieved during manufacturing. As a result, it offers advantages such as high volumetric efficiency, smooth operation, good flow uniformity, low noise, and high operating pressure. However, it is sensitive to contamination by hydraulic oil, has a complex structure, and is relatively expensive. 　　MCY14-1B: Quantitative piston pump 　　SCY14-1B: Manual variable piston pump 　　YCY14-1B: Pressure-variable piston pump 　　BCY14-1B: Electro-hydraulic control piston pump 　　PCY14-1B: Constant-pressure variable piston pump 　　The oil pumping mechanism of a piston pump consists of two sets of precision mating parts: the plunger and the barrel together form the plunger and barrel assembly (Figure 5-11), while the delivery valve and the delivery valve seat together form the delivery valve assembly. 　　The plunger and the barrel are a pair of precision-matched parts; after being ground to fit together, they cannot be interchanged. High precision, good surface finish, and excellent wear resistance are required for them, with a radial clearance of 0.002–0.003 mm. 　　Slanted grooves are cut on the cylindrical surface of the plunger head, and these grooves communicate with the top part through radial and axial holes; the purpose of this is to adjust the amount of oil supplied in each cycle ； The plunger sleeve is equipped with inlet and return oil holes, both of which are connected to the low-pressure oil chamber in the pump upper body. After the plunger sleeve is inserted into the pump upper body, it should be positioned using set screws. 　　The method of changing the oil supply volume varies depending on the position of the inclined groove on the plunger head. 　　The oil outlet valve and the oil outlet valve seat also form a precision pair; after being ground together, they cannot be interchanged, with a fitting clearance of 0.01 mm. 　　The oil outlet valve is a one-way valve; under the force of a spring, the conical surface at the upper part of the valve fits tightly with the valve seat. Its function is to isolate the high-pressure oil pipe from the cavity at the upper end of the plunger when supply is stopped, thereby preventing oil from the high-pressure oil pipe from flowing back into the fuel injection pump. 　　The lower part of the oil outlet valve has a cross-sectional shape that provides guidance while also allowing diesel to pass through. Beneath the conical surface of the oil outlet valve, there is a small cylindrical surface known as the pressure-reduction ring; its function is to cause the oil pressure in the high-pressure oil pipe to drop rapidly at the end of oil supply, thereby preventing dripping at the nozzle. When the annular band falls into the valve seat, the volume above it increases rapidly, the pressure drops quickly, and spraying stops swiftly. Working stage: During operation, the cam on the fuel pump’s camshaft, together with the plunger spring, forces the plunger to move up and down reciprocally, thereby carrying out the task of pumping fuel. The fuel pumping process can be divided into the following three stages. 　　Oil inlet process: When the protruding part of the cam rotates past, the plunger moves downward under the force of the spring. A vacuum is created in the space above the plunger (referred to as the oil pumping chamber). When the upper surface of the plunger opens the oil inlet hole in the plunger sleeve, the diesel fuel contained in the oil passages of the pump’s upper part enters the oil pumping chamber through this hole. Once the plunger reaches its lower dead center, the oil inlet process is complete. 　　Fuel supply process: When the camshaft rotates and the protruding part of the cam lifts the roller body, the plunger spring is compressed, causing the plunger to move upward. As a result, the fuel is under pressure, and some of it flows back through the fuel holes into the oil chamber in the upper part of the fuel injection pump. When the top surface of the plunger covers the upper edge of the oil inlet hole in the sleeve, the very small clearance between the plunger and the sleeve (0.0015–0.0025 mm) turns the pump chamber at the top of the plunger into a sealed oil volume. As the plunger continues to rise, the oil pressure in this pump chamber increases rapidly. When the pump pressure exceeds the spring force of the oil outlet valve plus the residual pressure in the high-pressure oil pipe, the oil outlet valve is pushed open, and the high-pressure diesel enters the high-pressure oil pipe before being injected into the combustion chamber through the injectors. 　　Oil return process: The plunger supplies oil upward; when it moves up to the inclined groove on the plunger (the point where oil supply stops) and this groove connects with the oil return hole on the sleeve, the low-pressure oil circuit in the pumping chamber becomes connected to the central hole, the radial holes, and the inclined groove on the plunger head. As a result, the oil pressure drops suddenly, and the outlet valve closes quickly due to the force of the spring, thereby stopping the oil supply. Thereafter, the plunger moves upward again; once the protruding part of the cam has passed by, the plunger moves downward under the action of the spring. At this point, the next cycle begins. 　　Conclusion: Based on the above discussion, the following conclusions can be drawn: ① The total stroke L of the plunger’s reciprocating motion remains constant and is determined by the lift of the cam. 　　② The amount of fuel supplied per cycle by the plunger depends on the fuel supply stroke, which is variable and not controlled by the camshaft. 　　③ The start time of fuel supply does not change with variations in the fuel supply stroke. 　　④ Rotating the plunger can change the timing of fuel supply, thereby altering the amount of fuel supplied. 　　3. Domestic series plunger fuel injection pumps The domestic series of plunger pumps mainly include series such as A, B, P, Z, and I, II, III. Serialization is based on the varying fuel supply requirements corresponding to the power range of each diesel engine’s cylinder. Using the plunger stroke, the distance between the pump cylinders, and the structural design as a foundation, plunger diameters of different sizes are employed to create several types of injection pumps that provide varying amounts of fuel per working cycle, thereby meeting the needs of various diesel engines. 　　The working principles and structural types of domestic series fuel injection pumps are basically the same; taking the Type A pump as an example, the structure and working principle of the plunger-type fuel injection pump are explained. A plunger pump consists of four main components: the sub-pump, the oil flow control mechanism, the drive mechanism, and the pump body. The latest domestic intelligent plunger pumps are equipped with microprocessor-based intelligent control and LCD displays; they can communicate with computers and feature stable operating pressure, low pulsation, and easy operation. It is widely used in industries such as biochemistry, pharmaceuticals, chemicals, and environmental protection, meeting the requirements of these industries for continuous liquid transfer under constant pressure and flow rates. Key features: Features a dual-plunger design, resulting in low pressure fluctuations and a long lifespan for the gem ball ； 　　Imported gemstone plungers and balls are used to ensure precise flow control. Communication with a computer is possible via the RS232 interface, allowing for direct control from the computer ； 　　The contact medium material is resistant to corrosion by organic solvents ； 　　Built-in overvoltage protection and flow correction system ； 　　Large-screen LCD display ； 　　A well-designed exhaust device effectively removes bubbles from the liquid being transported. 　　Flow and pressure settings can be memorized; communication with a PLC is possible (customizable). Software functions: real-time display of current pressure, set pressure, and set flow rate ； The real-time curve displays the pump’s operating pressure. Flow rate and pressure can be set in two ways, offering speed and convenience ； It has a timing function, making it convenient to set the operating time of the pump ； The current working pressure can be saved for easy viewing ； It can print important parameters such as the current pressure. 　　Plug pumps are widely used in experiments for oil exploration, development, and evaluation, catalytic reactions and polymerization reactions in the petrochemical industry, the food and pharmaceutical sectors, liquid chromatography analysis, supercritical extraction, separation processes, nuclear science, environmental science, process equipment, laboratory equipment, as well as for the precise delivery of small amounts of various liquids. The various performance parameters of the TBP series of plug flow pumps can meet the requirements for studying the rheological properties of fluid flow in oil fields, filling the gap in equipment manufacturing in this field of experimental technology in China, and reaching the international advanced level of similar instruments.